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The objective of this study was to analyze the response of antioxidant parameters in soybean plants inoculated with newly isolated Bradyrhizobium japonicum and Bacillus subtilis strains as single and co-inoculants under drought stress. Bacterial strains were selected according to osmotic stress tolerance (in the presence of 36% PEG 6000) in appropriate liquid media. The effect of soybean inoculation was examined in a soil pot experiment in water deficit conditions (0 and 7 days withholding water). The influence of water stress and inoculation was evaluated in soybean leaves, roots, and nodules through guaiacol peroxidase (POX), ionically cell-wall-bound peroxidase (POD) activity, and ABTS˙+ radical cation scavenging capacity, as well as parameters of N-fixation efficiency. The results showed a significant influence of inoculation on constitutive and drought-induced antioxidant and N-fixation parameters. Inoculation increased the activity of POX (up to 116, 169, and 245%), POD (up to 116, 102, and 159%), and antioxidant capacity (up to 74, 76, and 81%) in soybean leaves, roots, and nodules under water deficit, respectively. Application of bacterial strains resulted in higher shoot, root, and nodule weight and nitrogen content both in non-stressed and drought stress conditions. Overall, co-inoculation had better effects on the investigated soybean parameters compared to single inoculation. Selection and application of bacterial strains with improved tolerance to drought stress is necessary in developing inoculants that would result in enhanced crop production under unfavorable environmental conditions. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) and rhizobia play a pivotal role in enhancing crop productivity, shaping microbial community structure, and improving soil quality, making them key components for sustainable ecosystem development. The symbiotic relationship between AMF and rhizobia is crucial for facilitating efficient biological nitrogen fixation and nutrient absorption, thereby reducing the dependence on chemical fertilizers and promoting sustainable agricultural practices. The findings of various studies, however, indicate that soil environment can impede the symbiotic relationship between AMF and rhizobia. We conducted a comprehensive meta-analysis of 158 articles from 1980 to 2022 to explore the synergistic interactions in legume–AMF–rhizobium systems and the potential mechanisms underlying this synergism. Our findings revealed that the inoculation with AMF and/or rhizobia significantly (p < 0.001) increased legume plant nitrogen content, phosphorus content, shoot biomass, yield, AMF colonization rate, and the number and weight of nodules compared to uninoculated controls (effect size d > 0). Moreover, there was a substantial synergistic effect between AMF and rhizobia (p < 0.001). Nevertheless, soil salinity stress, drought stress, and pH stress could hinder the positive effects of inoculation treatments, possibly due to the plant trade-off strategies under abiotic stress conditions. This research may potentially lead to new solutions for sustainable agricultural systems amidst the challenges posed by global climate change. [ABSTRACT FROM AUTHOR]

The increasing frequency and severity of drought, driven by global climate change, has emerged as a critical factor constraining the growth of landscaping trees in urban ecosystems. The local or non-local status of tree species is an important driver of plant function traits, which regulate plant performance. However, the differential impact of varying drought intensities on the functional traits of both non-local and local trees remains poorly understood. This study investigated the responses of leaf and root traits of seven typical tropical landscaping tree seedlings (three local species and four non-local species) to simulated drought conditions in a year-long greenhouse experiment. The results showed that drought significantly increased the specific leaf area, leaf thickness, and root exudate rate, while reducing root nitrogen content and leaf dry matter content, with differences observed between local and non-local species. The non-local species exhibited pronounced fluctuations in leaf and root traits between control and drought conditions. Local species tended to enhance the relationship between leaves and roots under drought, while non-local species showed a weakening of this relationship. Principal component analysis revealed that local species adopted a more conservative strategy under control conditions and a more acquisitive strategy under drought, while root strategies remained stable across conditions. The subordination function method in fuzzy mathematics identified Terminalia neotaliala (non-local) as the most drought-resistant species and Artocarpus heterophyllus (non-local) as the least drought-resistant species. Non-local species demonstrated greater drought resistance in leaf traits compared to local species, but the opposite was observed for root traits. These results underscore the importance of understanding the species-specific responses of local and non-local trees to drought stress. These findings provide a scientific basis for developing effective screening and management protocols for drought-resistant landscaping tree species. [ABSTRACT FROM AUTHOR]

• Different levels of drought stress result in changes in gene expression and reduce plant growth and development. • The proper concentration of nutrients can increase plant efficiency under stress and normal conditions. • Molybdenum can lead to dryness adjustment through different pathways, including the accumulation of osmolytes, increasing the activity of enzymes and reducing the content of oxidative markers. Drought stress is a multidimensional abiotic stress that negatively affects plant growth and yield. Therefore, identifying useful, low-cost, and low-risk solutions to deal with drought along with identifying tolerant plants is crucial for sustainable agriculture and crop production worldwide. In some cases, due to a lack of nutrients, even if there is enough moisture, the plants are still unable to absorb water. Increasing essential macro- and micronutrients may reduce the harmful effects of abiotic stresses, among which drought, while increasing yield. The essential element molybdenum (Mo) has a role in many processes such as photosynthesis, nitrogen (N) metabolism, hormone signaling and tolerance of abiotic stresses. Plants absorb Mo as molybdate anion (MoO 4 2−), which is the main common soluble form of Mo present in neutral to alkaline soils. Mo has a unique effect on the synthesis of hormones and enzymes, and thus affecting plant water relationships and response to environmental stresses. On the other hand, limited water resources and lack of access to adequate water for agricultural production in terms of quantity and quality risk compromising the uptake of Mo which is already critical in soils acidic and/or poor in this essential micronutrient. This study systematically investigated the response to Mo stress and provided valuable evidence for the efficacy of Mo as a candidate to temper the adverse effects of drought stress on crops. Further, this review article also explains the mechanistic actions exerted by Mo in alleviating the drastic effects of drought on crops. [ABSTRACT FROM AUTHOR]

Key message: Climate change can limit yields of naturally resilient crops, like sorghum, challenging global food security. Agriculture under an erratic climate requires tapping into a reservoir of flexible adaptive loci that can lead to lasting yield stability under multiple abiotic stress conditions. Domesticated in the hot and dry regions of Africa, sorghum is considered a harsh crop, which is adapted to important stress factors closely related to climate change. To investigate the genetic basis of drought stress adaptation in sorghum, we used a multi-environment multi-locus genome-wide association study (MEML-GWAS) in a subset of a diverse sorghum association panel (SAP) phenotyped for performance both under well-watered and water stress conditions. We selected environments in Brazil that foreshadow agriculture where both drought and temperature stresses coincide as in many tropical agricultural frontiers. Drought reduced average grain yield (Gy) by up to 50% and also affected flowering time (Ft) and plant height (Ph). We found 15 markers associated with Gy on all sorghum chromosomes except for chromosomes 7 and 9, in addition to loci associated with phenology traits. Loci associated with Gy strongly interacted with the environment in a complex way, while loci associated with phenology traits were less affected by G × E. Studying environmental covariables potentially underpinning G × E, increases in relative humidity and evapotranspiration favored and disfavored grain yield, respectively. High temperatures influenced G × E and reduced sorghum yields, with a ~ 100 kg ha−1 average decrease in grain yield for each unit increase in maximum temperature between 29 and 38 °C. Extreme G × E for sorghum stress resilience poses an additional challenge to breed crops for moving, erratic weather conditions. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Research efforts in plant biology have often been focused on sequenced and well‐studied 'model' organisms. Despite the advent of relatively inexpensive genome sequencing, most plant taxonomic groups are underrepresented, with few species that 'represent' the diversity of whole genera. This study describes an economical guide to sequencing a non‐model organism, which may be useful in reducing the cost of sequencing more species within genera and across plant life. This method was used to develop Kalanchoë blossfeldiana as a resource for comparing C3 and the water‐conserving mode of photosynthesis known as Crassulacean acid metabolism (CAM) within the same plant. Summary: Despite the increasing number of well‐studied plant species with well‐annotated genomes across plant life, there are few densely sampled genera with more than a couple of genome sequences representing the diversity of whole genera. Here, we develop an economic approach to full‐genome sequencing that could be used to sequence many species within a genus. We made use of the Nanopore rapid sequencing kit to assist in plant genome assembly, dramatically reducing the cost.Here we applied this method to cost‐effectively develop genomic resources for Kalanchoë blossfeldiana, a commercially important ornamental, in which Crassulacean Acid Metabolism (CAM), a water‐conserving mode of photosynthesis can be induced. We present a physiological and biochemical characterisation of Kalanchoe blossfeldiana with its nuclear and chloroplastic genome and a comparative C3, CAM dusk transcriptome.We apply this approach to a complex tetraploid genome, making use of a relative species for chromosomal scaffolding to reduce assembly ploidy, we provide a resource for future gene expression studies. We highlight its limitations, e.g. the need for deeper sequencing to accurately resolve genome structure and haplotypes without using a relative species for scaffolding.The study demonstrates the merits of K. blossfeldiana as a comparative system for studying C3 and CAM within a plant and has identified substantial changes in the dusk transcriptome between young C3 and mature CAM K. blossfeldiana leaves in response to age‐induced CAM, and shows that in the absence of abiotic stress, CAM induction still involves the engagement of drought and abscisic acid (ABA) response pathways. [ABSTRACT FROM AUTHOR]

Key message: Wheat TaCDPK1-5A plays critical roles in mediating drought tolerance through regulating osmotic stress-associated physiological processes. Calcium (Ca2+) acts as an essential second messenger in plant signaling pathways and impacts plant abiotic stress responses. This study reported the function of TaCDPK1-5A, a calcium-dependent protein kinase (CDPK) gene in T. aestivum, in mediating drought tolerance. TaCDPK1-5A sensitively responded to drought and exogenous abscisic acid (ABA) signaling, displaying induced transcripts in plants under drought and ABA treatments. Yeast two-hybrid and co-immunoprecipitation assays revealed that TaCDPK1-5A interacts with the mitogen-activated protein kinase TaMAPK4-7D whereas the latter with ABF transcription factor TaABF1-3A, suggesting that TaCDPK1-5A constitutes a signaling module with above partners to transduce signals initiated by drought/ABA stressors. Overexpression of TaCDPK1-5A, TaMAPK4-7D and TaABF1-3A enhanced plant drought adaptation by modulating the osmotic stress-related physiological indices, including increased osmolyte contents, enlarged root morphology, and promoted stomata closure. Yeast one-hybrid assays indicated the binding ability of TaABF1-3A with promoters of TaP5CS1-1B, TaPIN3-5A, and TaSLAC1-3-2A, the genes encoding P5CS enzyme, PIN-FORMED protein, and slow anion channel, respectively. ChIP-PCR and transcriptional activation assays confirmed that TaABF1-3A regulates these genes at transcriptional level. Moreover, transgene analysis indicated that these stress-responsive genes positively regulated proline biosynthesis (TaP5CS1-1B), root morphology (TaPIN3-5A), and stomata closing (TaSLAC1-3-2A) upon drought signaling. Positive correlations were observed between yield and the transcripts of TaCDPK1-5A signaling partners in wheat cultivars under drought condition, with haplotype TaCDPK1-5A-Hap1 contributing to improved drought tolerance. Our study concluded that TaCDPK1-5A positively regulates drought adaptation and is a valuable target for molecular breeding the drought-tolerant cultivars in T. aestivum. [ABSTRACT FROM AUTHOR]

Key message: CRISPR/Cas9-mediated knockout of SlWOX4 gene in tomato enhances tolerance to drought stress. Drought stress is one of the major abiotic factors that seriously affects plant growth and crop yield. WUSCHEL-related homeobox (WOX) transcription factors are involved in plant growth, development and stress response. However, little is known about the role of WOX genes in drought tolerance in tomato. Here, SlWOX4, a member of the WOX family in tomato, was functionally characterized in mediating drought tolerance. SlWOX4 was homologous to Nicotiana tabacum NtWOX4 with a conserved HD domain, and was localized in the nucleus. SlWOX4 was significantly down-regulated by drought and abscisic acid (ABA) treatments. The loss-of-function mutations of SlWOX4 produced using the CRISPR–Cas9 system in tomato improved drought tolerance by reducing water loss rate and enhancing stomatal closure. In addition, the wox4 lines exhibited reduced accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), increased antioxidant enzyme activity, proline contents and ABA contents under drought stress. Moreover, gene editing of SlWOX4 in tomato enhanced drought tolerance by regulating the expression of genes encoding antioxidants and ABA signaling molecules. In summary, SlWOX4 gene might negatively regulate drought stress tolerance in tomato and has great potential as a drought-resistant crop-breeding target genes. [ABSTRACT FROM AUTHOR]

Summary: The globally changing climatic condition is increasing the incidences of drought in several parts of the world. This is predicted and already shown to not only impact plant growth and flower development, but also plant–pollinator interactions and the pollination success of entomophilous plants. However, there is a large gap in our understanding of how drought affects the different flowers and pollen transfer among flowers in sexually polymorphic species.Here, we evaluated in monoecious Styrian oil pumpkin, and separately for female and male flowers, the responses of drought stress on flower production, petal size, nectar, floral scent and visitation by bumblebee pollinators.Drought stress adversely affected all floral traits studied, except floral scent. Although both flower sexes were adversely affected by drought stress, the effects were more severe on female flowers, with most of the female flowers even aborted before opening. The drought had negative effects on floral visitation by the pollinators, which generally preferred female flowers.Overall, our study highlights that the two flower sexes of a monoecious plant species are differently affected by drought stress and calls for further investigations to better understand the cues used by the pollinators to discriminate against male flowers and against flowers of drought‐stressed plants. See also the Commentary on this article by Buchmann & Papaj, 244: 746–748. [ABSTRACT FROM AUTHOR]

Abiotic stresses, such as heat, drought and salinity, affect the development of wheat crop and hinder its expansion to the central region of Brazil. The identification of genotypes tolerant to these conditions is important for improving yield performance. The present research evaluated the impact of different abiotic stresses on germination and seedling development and selected wheat genotypes tolerant to these stresses, using multi-trait analysis. Heat, drought and salinity stresses were induced in seeds of 23 wheat genotypes. Seed germination, seedling length and dry mass were evaluated. An adaptability and stability model and a multi-trait selection index were applied to the data. Drought and salinity negatively affected the development of seedlings of the 23 evaluated genotypes. However, the VI 14055, ORS Madre Pérola and BRS 404 genotypes conferred the best adaptability and stability results and were selected by the MGIDI, which revealed that great performance can be achieved in regions with potential for abiotic stress, in the early stages of development. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rubus idaeus is one of the primary cultivated species of raspberries, renowned for its appealing color, distinctive flavor and numerous health benefits. WIP proteins, which contain three conserved amino acids (W: Tryptophan, I: Isoleucine, P: Proline) and four zinc finger motifs in a highly conserved C-terminal region, are members of the A1d subgroup of C2H2 zinc finger proteins. Drought is one of the main limiting factors of plant growth and development, which restricts the cultivation and utilization of raspberry in northwest China. In this study, to obtain candidate genes for drought resistance, we identified key related genes, RiWIPs, from R. idaeus and analyzed their bioinformation and tissue stress response expression to drought. We found that there are three RiWIPs in R. idaeus and they are located on chromosomes 3, 4 and 6 of R. idaeus, respectively. The open reading frames (ORFs) of the RiWIPs ranged from 870 to 1056 bp in length, encoding 289 to 372 amino acid residues. The proteins were highly conserved and feature diverse conserved motifs. The promoters of the RiWIPs contained abundant cis-elements related to growth, development and stress response. Tissue-specific expression analysis revealed that the RiWIPs were expressed in the leaves, stems and roots of both drought-susceptible and drought-tolerant cultivars, except for RiWIP2, which was only expressed in the roots of the drought-tolerant one. Under drought stress, the transcriptional activity of the RiWIPs was increased to different degrees with specificity in the leaves, stems and roots. Our study demonstrated the role of WIP genes in raspberry drought response and provided a marker gene, RiWIP2, for drought resistance and candidate genes for subsequent drought-resistant breeding of R. idaeus. [ABSTRACT FROM AUTHOR]

This experiment was conducted at the Fruit Research Institute, MAREM, Eğirdir-Isparta, Turkey, to detect the effects of different glycine betaine doses in drought stress conditions on young pear trees in 2019. The pear trees used in the study were one-year-old Deveci (Pyrus Comminus L.) variety grafted onto OHxF 333 rootstock. There were three different irrigation treatments in the experiment. Treatments were I100 treatment—available soil water reached field capacity for each irrigation, 100% (control); I50 treatment—irrigated with 50% of the water used in the I100 treatment (50% water deficit, moderate stress); I25 treatment—irrigated with 25% of the water used in the I100 treatment (75% water deficit, severe stress). Four different GB doses were used: GB0: 0, control; GB1: 1 mg L−1; GB5: 5 mg L−1; and GB10: 10 mg L−1. GB was not applied to pear trees in the I100 treatment. That is, there were nine different treatments in this study. GB applications provided a 19% increase in Pn of both the I25 and I50 treatments. According to the results of gsw, gsw increased between 18.0% and 27.8% for GB50 and GB25 treatments, respectively. In total, 10.9% and 14.8% increasing rates in shoot length were detected in GB10 applications in both the 50% and 75% water deficit treatments. The highest trunk diameter and fresh root weight results were determined in 10 mg L−1 GB dose applications under 50% water deficit conditions (I50GB10). [ABSTRACT FROM AUTHOR]

Aroma plays a pivotal role in defining tea quality and distinctiveness, and tea producers have often observed that specific drought conditions are closely associated with the formation and accumulation of characteristic aroma compounds in tea leaves. However, there is still limited understanding of the differential strategies employed by various tea cultivars in response to drought stress for the accumulation of key volatile aroma compounds in fresh tea leaves, as well as the associated metabolic pathways involved in aroma formation. In this study, two widely cultivated tea cultivars in China, Fuding Dabai (FD) and Wuniuzao (WNZ), were examined to assess the impact of mild field drought stress on the composition and accumulation of key volatile aroma compounds in fresh leaves using headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) and headspace solid phase micro-extraction gas chromatography–mass spectrometry (HS-SPME-GC-MS) technologies. Results revealed that drought stress led to a substantial increase in the diversity of volatile compounds (VOCs) in FD, while WNZ exhibited a notable rise in low-threshold VOC concentrations, amplifying sweet, floral, fruity, and earthy aroma profiles in post-drought fresh leaves. Through partial least squares discriminant analysis (PLS-DA) of HS-GC-IMS and HS-SPME-GC-MS data, integrating variable importance projection (VIP) scores and odor activity values (OAVs) above 1, 9, and 13, key odor-active compounds were identified as potential markers distinguishing the drought responses in the two cultivars. These compounds serve as crucial indicators of the aromatic profile shifts induced by drought, providing insights into the differential metabolic strategies of the cultivars. Additionally, KEGG enrichment analysis revealed 12 metabolic pathways, such as terpenoid biosynthesis, fatty acid synthesis, cutin, suberine, and wax biosynthesis, and phenylalanine metabolism, which may play crucial roles in the formation and accumulation of VOCs in tea leaves under drought stress. These findings provide a comprehensive framework for understanding the cultivar-specific mechanisms of aroma formation and accumulation in tea leaves under mild drought conditions. [ABSTRACT FROM AUTHOR]

Drought is the most significant abiotic stress that impedes agroforestry development. In nature, drought tolerance also depends on the ability to compensate after water restoration. Dark septate endophytes (DSEs) are believed to enhance plant tolerance in drought environments. However, the compensatory mechanisms of DSEs for rehydration after drought stress have not been reported. To assess the drought tolerance and compensatory capacity of DSEs, the following DSEs were investigated in this study using solid–liquid screening and potting tests under different drought gradients, rehydration conditions, and field water-holding capacities: Stagonosporopsis lupini, Microsphaeropsis cytisi, Macrophomina pseudophaseolina, Paraphoma radicina, Alternaria alstroemeriae, Alternaria tellustris, and Papulaspora equi. The results showed that M. pseudophaseolina reached the maximum diameter for plate growth in only 4 d. In a liquid shaker, the biomass of S. lupini peaked after rehydration. The Mantel heatmap indicated that lipid metabolites were significantly expressed in M. pseudophaseolina and S. lupini under drought stress. Correlations between drought tolerance indexes and amino acid metabolites increased dramatically in both DSEs after rehydration. Moreover, in rehydration after drought, the treatments inoculated with M. pseudophaseolina and S. lupini showed significant increases in root weight of 20.36% and 23.82%, respectively, compared with the uninoculated treatment. [ABSTRACT FROM AUTHOR]

Due to shallow root systems, potato is a particularly drought-sensitive crop. To counteract these limitations, the application of plant growth-promoting microorganisms (PGPMs) is discussed as a strategy to improve nutrient acquisition and biotic and abiotic stress resilience. However, initial root colonization by PGPMs, in particular, can be affected by stress factors that negatively impact root growth and activity or the survival of PGPMs in the rhizosphere. In this study, perspectives for the use of commercial silicate-based soil conditioners (SCs) supposed to improve soil water retention were investigated. The SC products were based on combinations with lignocellulose polysaccharides (Sanoplant® = SP) or polyacrylate (Geohumus® = GH). It was hypothesized that SC applications would support beneficial plant–inoculant interactions (arbuscular mycorrhiza, AM: Rhizophagus irregularis MUCL41833, and Pseudomonas brassicacearum 3Re2-7) on a silty loam soil–sand mixture under water-deficit conditions (6–12 weeks at 15–20% substrate water-holding capacity, WHC). Although no significant SC effects on WHC and total plant biomass were detectable, the SC-inoculant combinations increased the proportion of leaf biomass not affected by drought stress symptoms (chlorosis, necrosis) by 66% (SP) and 91% (GH). Accordingly, osmotic adjustment (proline, glycine betaine accumulation) and ROS detoxification (ascorbate peroxidase, total antioxidants) were increased. This was associated with elevated levels of phytohormones involved in stress adaptations (abscisic, jasmonic, salicylic acids, IAA) and reduced ROS (H2O2) accumulation in the leaf tissue. In contrast to GH, the SP treatments additionally stimulated AM root colonization. Finally, the SP-inoculant combination significantly increased tuber biomass (82%) under well-watered conditions, and a similar trend was observed under drought stress, reaching 81% of the well-watered control. The P status was sufficient for all treatments, and no treatment differences were observed for stress-protective nutrients, such as Zn, Mn, or Si. By contrast, GH treatments had negative effects on tuber biomass, associated with excess accumulation of Mn and Fe in the leaf tissue close to toxicity levels. The findings suggest that inoculation with the PGPMs in combination with SC products (SP) can promote physiological stress adaptations and AM colonization to improve potato tuber yield, independent of effects on soil water retention. However, this does not apply to SC products in general. [ABSTRACT FROM AUTHOR]

Woody biomass serves as a renewable resource for various industries, including pulp and paper production, construction, biofuels, and electricity generation. However, the molecular mechanisms behind biomass traits are poorly understood, which significantly curtails the speed and efficiency of their improvement. We used activation tagging to discover genes that can positively affect tree biomass-associated traits. We generated and screened under greenhouse conditions a population of 2,700 independent activation tagging lines. A total of 761 lines, which had significantly and positively affected at least one biomass-associated trait, were discovered. The tag was positioned in the genome for forty lines which were affected in multiple traits and activation of proximal genes validated for a subset. For two lines we fully recapitulated the phenotype of the original lines through overexpression. Moreover, the overexpression led to more pronounced and additional improvements, not observed in the original lines. Importantly, the overexpression of a Fasciclinlike gene (PtaFLA10) and a Patatin-like gene (PtaPAT) was found to substantially improve biomass, with a 40% increase in dry-stem weight, and enhance drought tolerance, respectively. Additionally, PtaPAT overexpression increased cellulose content, which is crucial for biofuel production. Our work shows that the activation tagging approach applied even on a non-genome saturation scale in a poplar tree can be successfully used for the discovery of genes positively modify biomass productivity. Such dominant forward genetics approaches can aid in biotechnological manipulation of woody biomass traits and help unravel the functions and mechanisms of individual genes, gene families, and regulatory modules. [ABSTRACT FROM AUTHOR]

Picea mongolica is a rare and valuable tree species in China, having high tolerance for drought, cold, and sand burial. The late embryogenesis abundant protein (LEA protein) is a crucial transcription factor that plays a key role in both plant embryonic development and stress response. LEA genes have, however, not yet been reported in P. mongolica. In this study, through the analysis of genome data from Picea abies and transcriptome data from P. mongolica, a total of 49 PmLEAs were discovered and categorized into eight subfamilies based on their Pfam domain and phylogenetic relationship. RNA-Seq research revealed that 37 PmLEAs were differentially expressed at various stages of embryonic development. Using qRT-PCR, we found that most PmLEAs responded strongly to drought stress, with genes in the same subfamily exhibiting identical expression patterns. In particular, PmLEA25 is the most highly induced by drought treatment. Furthermore, we heterologously transformed PmLEA25 into Arabidopsis. The overexpression of PmLEA25 remarkably increased the germination rate, root length, and antioxidant capacity in Arabidopsis under drought treatment, compared with WT. The results serve as a point of reference for gaining a deeper comprehension of the function of PmLEA25 in the molecular process of stress resistance in P. mongolica. Additionally, they offer significant genetic materials for the purpose of breeding stress-resistant spruce species. [ABSTRACT FROM AUTHOR]

The seedling stage is crucial for plant establishment in natural and agricultural ecosystems. Some species have reduced germination rates and are sensitive to environmental stresses, making this stage even more critical. In this study, we employed sublethal stress levels in seeds to enhance germination responses and increase survival of seedlings susceptible to water deficiency. Hydration and dehydration cycles in seeds were applied to investigate their effects on germination parameters and subsequent seedling performance under water deficit conditions. The time of hydration and dehydration was based on triphasic imbibition and drying curves and applied up to three times prior germination. Results revealed increased germination rate (%G) and decreased time to reach 50% germination (T50) after hydration and dehydration cycles. Additionally, cyclically treated seeds produced seedlings with a higher survival rate under water deficit, faster growth rates, and greater dry matter production. The Dickson quality index and drought tolerance indices improved, while the stress susceptibility index decreased. These findings indicate that hydration and dehydration cycles in the seeds induce changes in the seedlings, modifying their basal stress response levels and contributing to the production of hardier seedlings capable of coping with environmental stresses. These responses are anchored in plant stress memory acquired after sublethal exposure to stress levels. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Drought, a significant environmental challenge, presents a substantial risk to worldwide agriculture and the security of food supplies. In response, plants can perceive stimuli from their environment and activate defense pathways via various modulating networks to cope with stress. Drought tolerance, a multifaceted attribute, can be dissected into distinct contributing mechanisms and factors. Osmotic stress, dehydration stress, dysfunction of plasma and endosome membranes, loss of cellular turgidity, inhibition of metabolite synthesis, cellular energy depletion, impaired chloroplast function, and oxidative stress are among the most critical consequences of drought on plant cells. Understanding the intricate interplay of these physiological and molecular responses provides insights into the adaptive strategies plants employ to navigate through drought stress. Plant cells express various mechanisms to withstand and reverse the cellular effects of drought stress. These mechanisms include osmotic adjustment to preserve cellular turgor, synthesis of protective proteins like dehydrins, and triggering antioxidant systems to counterbalance oxidative stress. A better understanding of drought tolerance is crucial for devising specific methods to improve crop resilience and promote sustainable agricultural practices in environments with limited water resources. This review explores the physiological and molecular responses employed by plants to address the challenges of drought stress. [ABSTRACT FROM AUTHOR]

Introduction: Nitraria tangutorum Bobr., a prominent xerophytic shrub, exhibits remarkable adaptability to harsh environment and plays a significant part in preventing desertification in northwest China owing to its exceptional drought and salinity tolerance. Methods: To investigate the drought-resistant mechanism underlying N. tangutorum, we treated 8-week-old seedlings with polyethylene glycol (PEG)- 6000 (20%, m/m) to induce drought stress. 27 samples from different tissues (leaves, roots and stems) of N. tangutorum at 0, 6 and 24 h after drought stress treatment were sequenced using PacBio single-molecule real-time (SMRT) sequencing and Illumina RNA sequencing to obtain a comprehensive transcriptome. Results: The PacBio SMRT sequencing generated 44,829 non-redundant transcripts and provided valuable reference gene information. In leaves, roots and stems, we identified 1162, 2024 and 232 differentially expressed genes (DEGs), respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that plant hormone signaling and mitogen-activated protein kinase (MAPK) cascade played a pivotal role in transmitting stress signals throughout the whole N. tangutorum plant following drought stress. The interconversion of starch and sucrose, as well as the biosynthesis of amino acid and lignin, may represent adaptive strategies employed by N. tangutorum to effectively cope with drought. Transcription factor analysis showed that AP2/ ERF-ERF, WRKY, bHLH, NAC and MYB families were mainly involved in the regulation of drought response genes. Furthermore, eight physiological indexes, including content of proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), total amino acid and soluble sugar, and activities of three antioxidant enzymes were all investigate after PEG treatment, elucidating the drought tolerance mechanism from physiological perspective. The weighted gene co-expression network analysis (WGCNA) identified several hub genes serve as key regulator in response to drought through hormone participation, ROS cleavage, glycolysis, TF regulation in N. tangutorum. Discussion: These findings enlarge genomic resources and facilitate research in the discovery of novel genes research in N. tangutorum, thereby establishing a foundation for investigating the drought resistance mechanism of xerophyte. [ABSTRACT FROM AUTHOR]

Background: Precision phenotyping of short-term transpiration response to environmental conditions and transpiration patterns throughout wheat development enables a better understanding of specific trait compositions that lead to improved transpiration efficiency. Transpiration and related traits were evaluated in a set of 79 winter wheat lines using the custom-built "DroughtSpotter XXL" facility. The 120 l plant growth containers implemented in this phenotyping platform enable gravimetric quantification of water use in real-time under semi-controlled, yet field-like conditions across the entire crop life cycle. Results: The resulting high-resolution data enabled identification of significant developmental stage-specific variation for genotype rankings in transpiration efficiency. In addition, for all examined genotypes we identified the genotype-specific breakpoint in transpiration in response to increasing vapour pressure deficit, with breakpoints ranging between 2.75 and 4.1 kPa. Conclusion: Continuous monitoring of transpiration efficiency and diurnal transpiration patterns enables identification of hidden, heritable genotypic variation for transpiration traits relevant for wheat under drought stress. Since the unique experimental setup mimics field-like growth conditions, the results of this study have good transferability to field conditions. [ABSTRACT FROM AUTHOR]

Grain filling is a critical process for improving crop production under adverse conditions caused by climate change. Here, using a quantitative method, we quantified post-anthesis source–sink relationships of a large dataset to assess the contribution of remobilized pre-anthesis assimilates to grain growth for both biomass and nitrogen. The dataset came from 13 years of semi-controlled field experimentation, in which six bread wheat genotypes were grown at plot scale under contrasting temperature, water, and nitrogen regimes. On average, grain biomass was ~10% higher than post-anthesis above-ground biomass accumulation across regimes and genotypes. Overall, the estimated relative contribution (%) of remobilized assimilates to grain biomass became increasingly significant with increasing stress intensity, ranging from virtually nil to 100%. This percentage was altered more by water and nitrogen regimes than by temperature, indicating the greater impact of water or nitrogen regimes relative to high temperatures under our experimental conditions. Relationships between grain nitrogen demand and post-anthesis nitrogen uptake were generally insensitive to environmental conditions, as there was always significant remobilization of nitrogen from vegetative organs, which helped to stabilize the amount of grain nitrogen. Moreover, variations in the relative contribution of remobilized assimilates with environmental variables were genotype dependent. Our analysis provides an overall picture of post-anthesis source–sink relationships and pre-anthesis assimilate contributions to grain filling across (non-)environmental factors, and highlights that designing wheat adaptation to climate change should account for complex multifactor interactions. [ABSTRACT FROM AUTHOR]

Drought stress severely impedes plant growth, development, and yield. Therefore, it is critical to uncover the genetic mechanisms underlying drought resistance to ensure future food security. To identify the genetic controls of these responses in Sorghum, an agriculturally and economically important grain crop, an interspecific recombinant inbred line (RIL) population was established by crossing a domesticated inbred line of Sorghum bicolor (TX7000) with its wild relative, Sorghum propinquum. This RIL population was evaluated under drought conditions, allowing for the identification of quantitative trait loci (QTL) that contribute to drought resistance. We detected eight QTL in the drought population that explain a significant portion of the observed variation for four traits (height, aboveground biomass, relative water content, and leaf temperature/transpiration). The allelic effects of, and the candidate genes within, these QTL emphasize: (1) the influence of domestication on drought‐responsive phenotypes, such as height and aboveground biomass, and (2) how control of water uptake and/or loss can be driven by species‐specific plant architecture. Our findings shed light on the interconnected roles of shoot and root responses in drought resistance as it relates to regulation of water uptake and/or loss, while the detected allelic effects demonstrate how maintenance of grain production and yield under drought is a likely result of domestication‐derived drought tolerance. [ABSTRACT FROM AUTHOR]

Drought stress imposes a serious challenge to cultivate wheat, restricting its growth. Drought reduces the capability of plant to uptake essential nutrients. This causes stunted growth, development and yield. Traditional ways to increase wheat growth under drought stress have shortcomings. Using plant-growth-promoting rhizobacteria (PGPR) has proved feasible and eco-friendly way to enhance wheat growth even under the drought stress. Combining PGPR in consortiums further boosts up their effects. In this study, we have checked the efficacy of drought-tolerant Bacillus halotolerans, Pseudomonas sihuiensis and Bacillus atrophaeus in combination. These strains were allowed to grow on PEG 6000 with concentrations (-0.15, -0.49, -0.73 and − 1.2) Mega Pascal (MPa) alone and in combination. Furthermore, Fourier transmission infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used. Their biochemical traits such as solubilization of K, P and Zn and the synthesis of siderophore, indole acetic acid (IAA), protease, amylase, hydrogen cyanide (HCN) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase were done. In addition to this, we investigated the optimum folic acid concentration i.e 150 ppm for wheat against drought stress. We conducted a pot experiment to check the growth-enhancing and drought-mitigating effects of consortium and folic acid alone and in combination. As a result, we found a significantly increased wheat biomass, relative water content (RWC), chlorophyll content, antioxidants including glutathione reductase and total soluble sugars and protein content under all treatments. However, the combined treatment of bacterial consortium and folic acid showed maximum potential to boost wheat growth and survival even under drought. We also investigated the minerals uptake by wheat after the treatments and found maximum nutrient uptake under the co-effect of folic acid and bacterial consortium We believe this is the first study that has investigated the optimal dose of folic acid for wheat. Our research is also novel in that we seek to investigate the effects of folic acid along with a bacterial consortium comprising Bacillus halotolerans, Pseudomonas sihuiensis and Bacillus atrophaeus on wheat grown under the drought stress. Highlights: Bacillus halotolerans, Pseudomonas sihuiensis and Bacillus atrophaeus are drought tolerant strains. Their consortium significantly improves wheat growth under drought stress. 150 ppm of folic acid is the optimum concentration for wheat growth. Synergistic application of bacterial consortium and folic acid has shown promising wheat growth abilities. [ABSTRACT FROM AUTHOR]

Sexual reproduction through seeds is an effective way to renew plant populations and increase their genetic diversity, but seed germination process is complicated and relatively difficult due to the restriction of environmental conditions. Wetland plants that reproduce sexually through seeds may be affected by changes in moisture and temperature. This study aims to explore the ecological adaptation strategies of seed germination of Lilium concolor var. megalanthum under different hydrothermal conditions. Controlled experiments were conducted to investigate the germination performance of L. concolor var. megalanthum seeds at different temperatures (10°C, 15°C, 20°C, 25°C, and 30°C) and simulated drought stress conditions using PEG-6000 solutions (0%, 5%, 10%, 15%, and 20%). The results showed that temperature, drought stress, and their interaction significantly affected the days to first germination, germination percentage, coefficient of germination rate, germination energy, germination index, and vigor index of seeds (p<0.01). The germination percentage, germination index, and vigor index of seed were significantly higher at 25°C compared to other temperatures (p<0.01). The interaction between low temperature and drought stress significantly delayed the days to first germination. The inhibition of drought stress on seed germination was enhanced by PEG-6000 solution under high temperature. Under the conditions of 25°C and 5% PEG-6000 solution concentration, seeds of L. concolor var. megalanthum exhibited optimal germination parameters. At 10°C and 15°C, the seeds exhibited the highest tolerance to PEG-6000-simulated drought stress. Rehydration germination results showed that extreme temperatures and drought stress conditions inhibit seed germination of L. concolor var. megalanthum without damaging seed structure. The germination pattern of seeds under variable temperature and drought stress conditions reflects their adaptive strategies developed over longterm evolution to cope with the environmental conditions. [ABSTRACT FROM AUTHOR]

Introduction: With increasing drought stress due to climate change and water scarcity, the agricultural sector has sought innovative strategies to mitigate the detrimental effects on crop productivity. One approach that has received significant attention is the use of fertilizers and biostimulants as potential means of alleviating drought stress. Methods: In this study, five different irrigation levels including 100% (control), 80% (slight stress), 60% (mild stress), 40% (moderate stress), and 20% (severe stress) of field capacity (FC) and seaweed extract (SWE) at three concentrations (0, 5, and 10 g/L) were applied to the pots containing one-year-old licorice (Glycyrrhiza glabra L.) plants in a factorial completely randomized design experiment with three replications for eight weeks. Results and discussion: The glycyrrhizic acid content increased with water stress intensity without the application of SWE until severe (20% FC) water stress treatment. The application of 10 g/L SWE under 100% FC led to a significant increase in the glycyrrhizic acid value (32.5±0.889 mg/g DW) compared with non-SWE application (30.0±1.040 mg/g DW). The maximum glabridin content (0.270±0.010 mg/g DW) was obtained under irrigation of 20% field capacity with 10 g/L SWE application. In addition, the activity of the all studied enzymes such as APX (ascorbate peroxidase), CAT (catalase), POD (peroxidase), and SOD (superoxide dismutase) were boosted by increasing the water stress levels. The use of SWE further enhanced the increase of some of these metabolites and enzymes, which, in turn, helped the plant to tolerate stress conditions through the scavenging of more ROS (Reactive oxygen species), wherein for this purpose, the SWE 10 g/L was more effective than other concentration. The plants efficiently eliminated ROS driven from drought stress by both non-enzymatic and enzymatic systems. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) and other reactive nitrogen species (RNS) are considered to be signaling molecules in higher plants involved in the regulation of growth and development processes. However, the molecular mechanisms of their formation, removal, and participation in plant responses to adverse environmental stimuli remain largely unclear. Therefore, the aim of this study was to assess the influence of selected single stresses and combined stresses (i.e., Rhopalosiphum padi L. aphid infestation, drought, aphid infestation, and drought) and post-stress recovery on the contents of NO and peroxynitrite anion (ONOO−), as well as the levels of mRNA and protein nitration (i.e., the 8-nitroguanine and protein 3-nitrotyrosine amounts, respectively), in maize seedlings (Zea mays L.). Moreover, the expression patterns of the two tested genes (nos-ip, encoding nitric oxide synthase-interacting protein, and nr1, encoding nitrate reductase 1) involved in NO metabolism in maize plants were quantified. We identified significant intervarietal, time-course, and stress-dependent differences in the levels of the quantified parameters. Under the investigated stress conditions, the aphid-resistant Waza cv. seedlings were characterized by a higher and earlier NO accumulation and mRNA nitration level and an increased expression of the two target genes (nos-ip and nr1), compared to the aphid-susceptible Złota Karłowa cv. seedlings. Conversely, the Złota Karłowa plants responded with a greater elevation in the content of ONOO− and protein 3-nitrotyrosine than the Waza cv. plants The multifaceted role of NO and its derivatives in maize plants challenged by single and combined stresses, as well as during post-stress recovery, is discussed. [ABSTRACT FROM AUTHOR]

Blueberries (Vaccinium spp.) are extremely sensitive to drought stress. Flavonoids are crucial secondary metabolites that possess the ability to withstand drought stress. Therefore, improving the drought resistance of blueberries by increasing the flavonoid content is crucial for the development of the blueberry industry. To explore the underlying molecular mechanism of blueberry in adaptation to drought stress, we performed an integrated analysis of the metabolome and transcriptome of blueberry leaves under drought stress. We found that the most enriched drought-responsive genes are mainly involved in flavonoid biosynthesis and plant hormone signal transduction pathways based on transcriptome data and the main drought-responsive metabolites come from the flavonoid class based on metabolome data. The UDP-glucose flavonoid 3-O-glucosyl transferase (UFGT), flavonol synthase (FLS), and anthocyanidin reductase (ANR-2) genes may be the key genes for the accumulation of anthocyanins, flavonols, and flavans in response to drought stress in blueberry leaves, respectively. Delphinidin 3-glucoside and delphinidin-3-O-glucoside chloride may be the most important drought-responsive flavonoid metabolites. VcMYB1, VcMYBPA1, MYBPA1.2, and MYBPA2.1 might be responsible for drought-induced flavonoid biosynthesis and VcMYB14, MYB14, MYB102, and MYB108 may be responsible for blueberry leaf drought tolerance. ABA responsive elements binding factor (ABF) genes, MYB genes, bHLH genes, and flavonoid biosynthetic genes might form a regulatory network to regulate drought-induced accumulation of flavonoid metabolites in blueberry leaves. Our study provides a useful reference for breeding drought-resistant blueberry varieties. [ABSTRACT FROM AUTHOR]

Drought stress of crops is an important factor affecting their yield and sustainable agricultural development. Accurate diagnosis of crop drought stress is the basis for improving water resource utilization. Imaging technology can quickly, automatically, non-destructively, accurately acquire and analyze the phenotype characteristics of crops, providing a powerful new tool for crop science research. This paper focuses on the review of phenotype imaging analysis techniques for crop drought stress diagnosis. First, the single imaging technique for crop drought stress diagnosis was introduced, and then we introduced the fusion imaging technique for crop drought stress diagnosis. In the aspect of single imaging technology introduction, firstly, the principles of six phenotype imaging techniques including RGB imaging, 3D imaging, near-infrared imaging, hyperspectral imaging, chlorophyll fluorescence imaging and thermal imaging are introduced in this paper, and then we introduced research progress of the single imaging technology in crop drought stress phenotype analysis, beside the research achievements in crop drought stress in recent years were further summarized. Finally, the imaging technology was summarized and prospected at the end of each imaging technology introduction. In the fusion imaging technology of crop drought stress, this paper first summarized the research results of the automatic comprehensive phenotype imaging analysis platform of crop drought stress in recent years, and then summarized and analyzed the research of different fusion imaging methods, analyzed their advantages and disadvantages, and prospected the future research direction of fusion imaging technology in the end. With the horizontal and vertical comparative analysis of the research results of a single imaging technology, we found that RGB imaging technology has the lowest application cost and the most extensive application range, but the lowest accuracy. The 3D imaging solves the problem of crop occlusion in RGB imaging, improves the accuracy, and is widely used in high-throughput phenotype extraction platforms. The information on crop phenotype parameters can be obtained by near-infrared spectroscopy, chlorophyll fluorescence and hyperspectral imaging in a fast and non-destructive way. Among them, the application scope of NIR imaging is limited due to its limited ability to obtain phenotype information and relatively high cost. Chlorophyll fluorescence and hyperspectral imaging are better at obtaining physiological and biochemical parameters of crops, and are widely used in the fusion of imaging methods. Thermal images obtained by infrared thermal imaging are often used to obtain crop physiological parameters, and are also combined with visible light images for phenotype extraction. In the meantime, the method of obtaining crop phenotype by using the fusion of multiple imaging technologies has the advantages of different imaging technologies, which can effectively avoid the defects of a single imaging technology and make up for the deficiencies of obtaining single imaging phenotype parameters, so as to reflect the crop growth status more accurately and efficiently. More accurate feature extraction can be achieved by integrating various image information obtained by various imaging technologies and using artificial intelligence methods for integrated image processing. The use of fusion imaging technology to obtain crop phenotypes will be one of the important directions of crop drought stress phenotypes extraction in the future. Finally, according to the current development situation, future research on phenotypic imaging technology for crop drought stress diagnosis prospects, including the development of new devices and the combination of new artificial intelligence algorithms. [ABSTRACT FROM AUTHOR]

Background: Drought stress is a major limiting factor that affects forage yields, and understanding the drought resistance mechanism of plants is crucial for improving crop yields in arid areas. Alfalfa (Medicago sativa L.) is the most important legume plant, mainly planted in arid and semi-arid areas. However, the adaptability of alfalfa to drought stress and its physiological and molecular mechanisms of drought resistance remains unclear. Results: In this study, we analyzed the physiological and transcriptome responses of alfalfa cultivars with different drought resistances (drought-sensitive Gannong No. 3 (G3), drought-resistant Gannong No. 8 (G8), and strong drought-resistant Longdong (LD)) under drought stress at 0, 6, 12, and 24 h. LD had higher catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities and a higher soluble protein content, lower malondialdehyde (MDA) content, a lower O2·− production rate, and a lower H2O2 content than G8 and G3 (P < 0.05). The functional enrichment analysis, temporal expression pattern analysis, and weighted gene co-expression network analysis (WGCNA) of the differentially expressed genes (DEGs) showed phenylpropanoid biosynthesis, flavonoid biosynthesis, starch and sucrose metabolism, glycolysis/gluconeogenesis, glutathione metabolism, and biosynthesis of amino acid responses to drought stress in alfalfa. The differential expression of genes during phenylpropanoid biosynthesis, starch and sucrose metabolism, and the glutathione metabolism pathway was further studied, and it was speculated that PAL, COMT, 4CL, CCR, CAD, HXK, INV, SUS, WAXY, AGP, GST, and APX1 played important roles in the alfalfa drought stress response. Conclusions: The aim of this study was to enhance alfalfa drought resistance by overexpressing positively regulated genes and knocking out negatively regulated genes, providing genetic resources for the subsequent molecular-assisted breeding of drought-resistant alfalfa crops. [ABSTRACT FROM AUTHOR]

This study investigates the potential of ellagic acid (EA) to mitigate the effects of drought and aluminum (Al3+) stresses in maize by examining various morpho-physiochemical parameters and gene expressions. Maize (Zea mays L.) serves as a crucial global food source, but its growth and productivity are significantly hindered by drought and aluminum (Al3+) stresses, which lead to impaired root development, elevated levels of reactive oxygen species (ROS), diminished photosynthetic efficiency, and reduced water and mineral absorption. Recently, ellagic acid (EA), a polyphenolic compound with potent antioxidant properties, has been identified for its role in regulating plant growth and enhancing stress tolerance mechanisms. However, the specific mechanisms through which EA contributes to Al3+ and/or drought tolerance in plants remain largely unknown. The present study was conducted to examine the defensive role of EA (100 μg/mL) in some morpho-physiochemical parameters and the expression profiles of some stress-related genes (ZmCPK22, ZmXTH1, ZmHIPP4, ZmSGR, ZmpsbA, ZmAPX1, and ZmGST1) in drought (polyethylene glycol-6000 (PEG-6000), − 0.6 MPa) and aluminum chloride (AlCl3, 60 μM) stressed Zea mays Ada 523 grown in nutrient solution. Our results indicated that drought and aluminum chloride stresses affected root length, shoot height, H2O2 content, chlorophyll content (SPAD), electrolyte leakage (EL), and relative water content (RWC) of maize with several significant (P < 0.05) shifts up and down. Conversely, EA (100 μg/mL) treatment had a mitigating effect on these parameters. Moreover, EA also mitigated the antioxidant enzyme activities (superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX)), and regulated the expressions of aforementioned genes. These findings determined that EA treatment could efficiently improve the gene expressions and morpho-physiochemical parameters under drought and/or Al3+ stresses, thereby increasing the seedlings' adaptability to these stresses. [ABSTRACT FROM AUTHOR]

Introduction: Melatonin, a tryptophan-derived indoleamine metabolite with important roles in plant growth and defense, has recently been regarded as a new plant hormone. Maize is one of the most important cereal crops in the world. Although the melatonin receptor gene, ZmPMTR1, has already been identified, the genetic basis of melatonin biosynthesis in maize has still not been elucidated. Serotonin N-acetyltransferase (SNAT) is the enzyme that converts serotonin to N-acetylserotonin (NAS) or 5-methoxytryptamine (5MT) to melatonin in Arabidopsis and rice, but no SNAT encoding gene has been identified yet in maize. Methods: The bioinformatics analysis was used to identify maize SNAT genes and the enzyme activity of the recombinant proteins was determined through in vitro assay. The expression levels of ZmSNAT1 and ZmSNAT3 under drought and heat stresses were revealed by public RNA-seq datasets and qRT-PCR analysis. Results: We first identified three maize SNAT genes, ZmSNAT1, ZmSNAT2, and ZmSNAT3, through bioinformatics analysis, and demonstrated that ZmSNAT2 was present in only eight of the 26 cultivars analyzed. We then determined the enzyme activity of ZmSNAT1 and ZmSNAT3 using their recombinant proteins through in vitro assay. The results showed that both ZmSNAT1 and ZmSNAT3 could convert serotonin to NAS and 5-MT to melatonin. Recombinant ZmSNAT1 catalyzed serotonin into NAS with a higher catalytic activity (Km, 8.6 mM; Vmax, 4050 pmol/min/mg protein) than ZmSNAT3 (Km, 11.51 mM; Vmax, 142 pmol/min/mg protein). We further demonstrated that the 228th amino acid Tyr (Y228) was essential for the enzymatic activity of ZmSNAT1. Finally, we revealed that the expression of ZmSNAT1 and ZmSNAT3 varied among different maize cultivars and different tissues of a plant, and was responsive to drought and heat stresses. Discussion: In summary, the present study identified and characterized the first two functional SNAT genes in maize, laying the foundation for further research on melatonin biosynthesis and its regulatory role in plant growth and response to abiotic stresses. [ABSTRACT FROM AUTHOR]

Drought and salinity are significant challenges to global food security. This study investigated the interactive impacts of Piriformospora indica inoculation with salinity and drought stresses on rice. Two greenhouse experiments were conducted. The first experiment evaluated two P. indica inoculation levels and three salinity levels (0-, 50-, and 100-mM sodium chloride), while the subsequent experiment assessed two inoculation levels under three drought intensities (25%, 50%, and 100% of available water content). P. indica spores were inoculated following optimized seed disinfection and germination processes. The shoot and root biomass under salinity stress were consistently higher in inoculated plants compared to controls. Sodium concentrations in shoots and roots exhibited an overall upward trend, with the trend being less pronounced in inoculated plants due to increased potassium uptake. Under salinity stress, nitrogen, magnesium, and calcium concentrations significantly increased in inoculated plants. With increasing salinity, there was a significant increase in catalase enzyme activity and soluble carbohydrate concentrations across all treatments, with a greater increase in inoculated plants. Plants under drought stress experienced reduced root and shoot biomass, but inoculated plants maintained higher biomass. Increasing drought stress led to decreased nitrogen, magnesium, and calcium concentrations in all treatments, with the reduction being less severe in inoculated plants. Catalase enzyme activity and carbohydrate increased with rising drought stress, with the increase being more pronounced in inoculated plants compared to non-inoculated ones. By promoting plant growth, nutrient uptake, and stress tolerance, P. indica inoculation has a significant potential to enhance crop productivity in extreme climate conditions. [ABSTRACT FROM AUTHOR]

Fruit photosynthesis occurs in an internal microenvironment seldom encountered by a leaf (hypoxic and extremely CO2-enriched) due to its metabolic and anatomical features. In this study, the anatomical and photosynthetic traits of fully exposed green fruits of Quercus coccifera L. were assessed during the period of fruit production (summer) and compared to their leaf counterparts. Our results indicate that leaf photosynthesis, transpiration and stomatal conductance drastically reduced during the summer drought, while they recovered significantly after the autumnal rainfalls. In acorns, gas exchange with the surrounding atmosphere is hindered by the complete absence of stomata; hence, credible CO2 uptake measurements could not be applied in the field. The linear electron transport rates (ETRs) in ambient air were similar in intact leaves and pericarps (i.e., when the physiological internal atmosphere of each tissue is maintained), while the leaf NPQ was significantly higher, indicating enhanced needs for harmless energy dissipation. The ETR measurements performed on leaf and pericarp discs at different CO2/O2 partial pressures in the supplied air mixture revealed that pericarps displayed significantly lower values at ambient gas levels, yet they increased by ~45% under high CO2/O2 ratios (i.e., at gas concentrations simulating the fruit's interior). Concomitantly, NPQ declined gradually in both tissues as the CO2/O2 ratio increased, yet the decrease was more pronounced in pericarps. Furthermore, net CO2 assimilation rates for both leaf and pericarp segments were low in ambient air and increased almost equally at high CO2, while pericarps exhibited significantly higher respiration. It is suggested that during summer, when leaves suffer from photoinhibition, acorns could contribute to the overall carbon balance, through the re-assimilation of respiratory CO2, thereby reducing the reproductive cost. [ABSTRACT FROM AUTHOR]

AbstractIncreased drought and salinity is a threat to agriculture in arid and semiarid zone worldwide. Almond is nutritious, rich in minerals protein and fiber with increasing world demand and production. The objective was to determine the effect of drought and salinity stress on nutrient concentrations in almond trees. Almond is known as sensitive to salt stress compared to other trees. There are limited studies on almond nutrition uptake under salt and drought stress conditions. This study had three drought and four salinity levels, and combined applications for a total of 12 treatments each with three replications. Drought increased K, Mg, Ca, Na and Cl concentrations in leaves, yet, decreased B concentrations. Similarly under salinity, almond leaves increased in K, Mg and Ca concentrations (as well as in Na and Cl). This study showed that the nutrient uptake varies under drought and salt stress conditions. Mineral nutrition should be taken into consideration, fertilization needs to account for stress factors. [ABSTRACT FROM AUTHOR]

Rice yield is greatly constrained by drought stress. In Arabidopsis, XYLEM NAC DOMAIN 1 (XND1) gene regulates the xylem formation, efficiency of water transport, and the delicate equilibrium between drought tolerance and resistance to pathogens. However, diversity and the role of rice homologs of OsXND1 is not reported so far. This study hypothesized that the rice homolog of OsXND1 also regulates drought stress tolerance through modulation of root architecture. Initially, phylogenetic analysis identified two OsXND1 homologs (Os02g0555300 and Os04g0437000) in rice. Further, 14 haplotypes were identified in the OsXND1 of which Hap1 and Hap3 were major haplotypes. The association analysis of OsXND1 with 16 different traits, including 10 root traits, showed three SNPs (Chr02:20972728-Promoter variant; Chr02:20972791-5′ UTR variant, and Chr02:20973745-3′ UTR variant) were significantly associated with root area, root surface area, total root length, and convex hull area only under drought stress in indica rice. Besides, the superior haplotype of OsXND1 increased the root area, root surface area, total root length, and convex hull area by 46%, 40%, 38%, and 42%, respectively, under drought stress conditions. Therefore, the identified superior haplotype of OsXND1 can be utilized in haplotype breeding programs for the improvement of drought tolerance in rice. [ABSTRACT FROM AUTHOR]

Drought stress poses increasingly serious threats to agricultural production in the era of global climate change. Arbuscular mycorrhizal (AM) fungi are well-recognized biostimulants promoting plant tolerance to drought stress. Lipids are indispensable for AM fungal colonization, however, the involvement of lipid metabolism in the drought tolerance conferred by AM fungi is largely unknown. In this study, we inoculated Poncirus trifoliata (L.) with Rhizophagus irregularis DAOM197198 under no drought stress, medium drought stress and severe drought stress, with non-inoculation under respective treatments as control. Results indicated that AM fungal inoculation significantly promoted the drought tolerance of P. trifoliata (L.), with the effect size decreasing along with drought severity. Moreover, the effect size was significantly related to arbuscule abundance. Fatty acid profiling showed that the arbuscule abundance was determined by the AM-specific phospholipids (PLs), whose biosynthesis and delivery were inhibited by drought stress as revealed by qRT-PCR of FatM, RAM1 and STR/STR2. More interestingly, AM fungal inoculation increased the lipid allocation to total PLs and the unsaturation rate of total neutral lipids (NLs), probably indicating the involvement of non-AM-specific lipids in the increased drought tolerance. Taken together, our results demonstrate that lipid metabolism in AM mediates the increased drought tolerance conferred by AM fungal inoculation, with AM-specific and non-AM-specific lipids functioning therein in different ways. [ABSTRACT FROM AUTHOR]

Background: Drought is currently a global environmental problem, which inhibits plant growth and development and seriously restricts crop yields. Many plants exposed to drought stress can generate stress memory, which provides some advantages for resisting recurrent drought. DNA methylation is a mechanism involved in stress memory formation, and many plants can alter methylation levels to form stress memories; however, it remains unclear whether Medicago ruthenica exhibits drought stress memory, as the epigenetic molecular mechanisms underlying this process have not been described in this species. Methods: We conducted methylome and transcriptome sequencing to identify gene methylation and expression changes in plants with a history of two drought stress exposures. Results: Methylation analysis showed that drought stress resulted in an approximately 4.41% decrease in M. ruthenica genome methylation levels. The highest methylation levels were in CG dinucleotide contexts, followed by CHG contexts, with CHH contexts having the lowest levels. Analysis of associations between methylation and transcript levels showed that most DNA methylation was negatively correlated with gene expression except methylation within CHH motifs in gene promoter regions. Genes were divided into four categories according to the relationship between methylation and gene expression; the up-regulation of hypo-methylated gene expression accounted for the vast majority (692 genes) and included genes encoding factors key for abscisic acid (ABA) and proline synthesis. The hypo-methylation of the promoter and body regions of these two gene groups induced increased gene transcription levels. Conclusions: In conclusion, DNA methylation may contribute to drought stress memory formation and maintenance in M. ruthenica by increasing the transcription levels of genes key for ABA and proline biosynthesis. [ABSTRACT FROM AUTHOR]

Plants exposed to harsh external environments such as cold and drought display stunted growth and delayed development. WRKY proteins can bind to the cis-acting element W-box to activate or repress transcription of downstream target genes to regulate responses, including different abiotic and biotic stresses. In this experiment, Malus baccata (L.) Borkh was used to isolate the MbWRKY65 gene to study its cold and drought resistance functions. The outcomes demonstrated that MbWRKY65 is most similar to the apple MdWRKY65 protein. Its location in the nucleus is shown by subcellular localization data, which is in line with its role as a transcription factor. MbWRKY65 was expressed richer in roots and older leaves in response to cold and drought treatments. The transgenic tomato showed considerably reduced contents of malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide anion radical (O2−), and relative conductivity during cold and drought stress in contrast to wild-type (WT) and unloaded lines (UL), but greater contents of proline and chlorophyll, as well as higher activity of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). Stress-related genes (LeCBF1, LeABI3, LeABF4, LeCBF3, LeNCED1, and LeDREB1) in transgenic tomato plants were positively regulated under conditions of cold and drought, and in contrast to the WT and UL lines, the transgenic tomato showed a considerably greater expression level. In conclusion, MbWRKY65 actively contributes to plant tolerance to cold and drought. [ABSTRACT FROM AUTHOR]

Drought stress is a major threat leading to global plant and crop losses in the context of the climate change crisis. Brassinosteroids (BRs) are plant steroid hormones, and the BR signaling mechanism in plant development has been well elucidated. Nevertheless, the specific mechanisms of BR signaling in drought stress are still unclear. Here, we identify a novel Arabidopsis gene, BRZ INSENSITIVE LONG HYPOCOTYL 9 (BIL9), which promotes plant growth via BR signaling. Overexpression of BIL9 enhances drought and mannitol stress resistance and increases the expression of drought-responsive genes. BIL9 protein is induced by dehydration and interacts with the HD-Zip IV transcription factor HOMEODOMAIN GLABROUS 11 (HDG11), which is known to promote plant resistance to drought stress, in vitro and in vivo. BIL9 enhanced the transcriptional activity of HDG11 for drought-stress-resistant genes. BIL9 is a novel BR signaling factor that enhances both plant growth and plant drought resistance. [ABSTRACT FROM AUTHOR]

Climate change is a major global concern that has increased the frequency and intensity of extreme drought. Severe drought stress negatively affected tree survival and growth. Poplars are fast-growing trees that can effectively sequester atmospheric carbon dioxide, the most important greenhouse gas. Recently, poplar has attracted attention as a bioenergy fuel source, owing to its fast-growing traits and abiotic stress tolerance. However, the molecular mechanisms underlying drought tolerance in poplars remain uncertain. Therefore, we compared the transcriptomes of P. davidiana and its hybrid with Populus alba grown under drought stress. Before drought stress, genes related to root development processes were up-regulated, and aboveground tissue development genes were down-regulated in P. davidiana compared to P. alba × P. davidiana. After 6 days of drought treatment, P. alba × P. davidiana showed susceptibility to drought stress, whereas P. davidiana exhibited a resistant phenotype. At the transcriptional level, cell wall and lignin biosynthesis genes were up-regulated on day 6 of drought treatment. We concluded that P. davidiana showed more resistance to drought stress than its hybrid and that cell wall biosynthetic processes contributed to drought tolerance by preventing xylem damage. These results could provide valuable information for poplar breeding to improve drought stress tolerance. [ABSTRACT FROM AUTHOR]

Poplar tree is one of the most important tree species in wood production and protective forest construction. The poplar artificial forest cultivation is ranked first in the world. Current severe drought and typical abiotic stress under global warming can pose a great challenge to the production of wood raw materials and the protection of forest resources. A series of planting strategies (such as the identification of water-deficient plants) have been used to cultivate the poplar species of high drought tolerance against drought stress. These approaches are required for the rapid observation and analysis of the growth status of poplar saplings, in order to execute irrigation decisions or drought-resistant variety screening. Previous research has focused mainly on the detection of drought stress, where the macroscopic morphology of plants can be classified to predict the drought level. Only a few studies have been focused on the digital expression of water deficiency symptoms in plants. Alternatively, the water content of plants has been directly predicted using relatively complex and expensive sensing devices. In this article, a low-cost machine vision was adopted to realize the lant phenotyping of poplar saplings under drought stress. Firstly, an extraction framework of the poplar skeleton was proposed to identify the individual leaves and key nodes inside the plant using the YOLOv8-pose detection model, in order to extract the overall morphological and structural information of the plant. Secondly, the few-shot learning techniques were introduced, including the training dataset expansion (or considered as an automatic synthesis for datasets) using minimal manual annotation. The annotated leaves and stems were extracted from the images, and then added into a ‘component pool’. New images of the poplar plant were also selected randomly. All the individual leaves and the key points were detected (including the leaf tip, connection point between blade and petiole, and connection point between the petiole and the trunk). Among them, the few-shot learning was trained using 600 synthetic poplar images with only 10 manually annotated samples. Thirdly, the angles of the main vein and petiole in each leaf were calculated from the skeleton information of the poplar sapling. Furthermore, the frequency distribution vector was converted (ranges from -90° to 90°, with an interval of 10°) for the artificial intelligence-based modeling. Finally, partial least square discrimination analysis (PLSDA), support vector machine (SVM), multilayer perception (MLP), and convolutional neural network (CNN) classifiers were compared to evaluate the drought stress level. The optimal model was selected for the final drought-stress grading. The results showed that the YOLOv8-pose model with the few-shot learning performed the best in the leaf recognition and key point extraction tasks, where the mean average precision with 0.5 as the threshold for intersection over union (mAP50) values were 0.798 and 0.914, respectively. The effectiveness and reliability few-shot learning-based YOLOv8-pose model were also validated using an independent test dataset composed of real samples and accurate manual annotations. Meanwhile, the manual annotation cost was significantly reduced for YOLOv8-pose model training. Subsequently, the classification model with one-dimensional CNN and leaf angle frequency distribution was superior in the drought stress grading task, with the highest classification accuracy of 0.850. In addition, the improved models shared relatively small parameters (model size less than 7 MB) with high speed. Low-cost computing can be realized in cloud service platforms with limited sources or embedded systems (such as Nvidia Jetson series devices). The phenotyping can also provide new technical support to identify the water-deficient poplar saplings and screen the drought-resistant plants. [ABSTRACT FROM AUTHOR]

This study explored the quantitative inversion of the chlorophyll content in Paulownia seedling leaves under drought stress and analyzed the factors influencing the chlorophyll content from multiple perspectives to obtain the optimal model. Paulownia seedlings were selected as the experimental materials for the potted water control experiments. Four drought stress treatments were set up to obtain four types of Paulownia seedlings: one pair of top leaves (T1), two pairs of leaves (T2), three pairs of leaves (T3), and four pairs of leaves (T4). In total, 23 spectral transformations were selected, and the following four methods were adopted to construct the prediction model, select the best spectral preprocessing method, and explore the influence of water bands: partial least squares modeling with all spectral bands (all-band partial least squares, AB-PLS), principal component analysis partial least squares (PCA-PLS), correlation analysis partial least squares (CA-PLS), correlation analysis (water band) partial least squares, ([CA(W)-PLS]), and vegetation index modeling. Based on the prediction accuracy and the uniformity of different leaf positions, the optimal model was systematically explored. The results of the analysis of spectral reflectance showed significant differences at different leaf positions. The sensitive bands of chlorophyll were located near 550 nm, whereas the sensitive bands of water were located near 1440 and 1920 nm. The results of the vegetation index models indicate that the multiple-index models outperformed the single-index models. Accuracy decreased as the number of indicators decreased. We found that different model construction methods matched different optimal spectral preprocessing methods. First derivative spectra ( R ′ ) was the best preprocessing method for the AB-PLS, PCA-PLS, and CA-PLS models, whereas the inverse log spectra ( l o g (1 / R) ) was the best preprocessing method for the CA(W)-PLS model. Among the 14 indices, the green normalized difference vegetation index (GNDVI) was most correlated with the chlorophyll content sensitivity indices, and the water index (WI) was most correlated with the water sensitive indices. At the same time, the water band affected the cross validation accuracy. When characteristic bands were used for modeling, the cross validation accuracy was significantly increased. In contrast, when vegetation indices were used for modeling, the accuracy of the cross validation increased slightly but its predictive ability was reduced; thus, these changes could be ignored. We found that leaf position also affected the prediction accuracy, with the first pair of top leaves exhibiting the worst predictive ability. This was a bottleneck that limited predictive capability. Finally, we found that the CA(W)-PLS model was optimal. The model was based on 23 spectral transformations, four PLS construction methods, water bands, and different leaf positions to ensure systematicity, stability, and applicability. [ABSTRACT FROM AUTHOR]

Dwarf bamboo (Fargesia denudata) is a crucial food source for the giant pandas. With its shallow root system and rapid growth, dwarf bamboo is highly sensitive to drought stress and nitrogen deposition, both major concerns of global climate change affecting plant growth and rhizosphere environments. However, few reports address the response mechanisms of the dwarf bamboo rhizosphere environment to these two factors. Therefore, this study investigated the effects of drought stress and nitrogen deposition on the physicochemical properties and microbial community composition of the arrow bamboo rhizosphere soil, using metagenomic sequencing to analyze functional genes involved in carbon and nitrogen cycles. Both drought stress and nitrogen deposition significantly altered the soil nutrient content, but their combination had no significant impact on these indicators. Nitrogen deposition increased the relative abundance of the microbial functional gene nrfA, while decreasing the abundances of nirK, nosZ, norB, and nifH. Drought stress inhibited the functional genes of key microbial enzymes involved in starch and sucrose metabolism, but promoted those involved in galactose metabolism, inositol phosphate metabolism, and hemicellulose degradation. NO3−-N showed the highest correlation with N-cycling functional genes (p < 0.01). Total C and total N had the greatest impact on the relative abundance of key enzyme functional genes involved in carbon degradation. This research provides theoretical and technical references for the sustainable management and conservation of dwarf bamboo forests in giant panda habitats under global climate change. [ABSTRACT FROM AUTHOR]

Osmanthus fragrans, a native to China, is renowned as a highly popular gardening plant. However, this plant faces significant challenges from drought stress, which can adversely affect its flowering. In this study, we found that the plasma membrane-localized gene OfPIP2 exhibited a substantial upregulation during the flowering stages and in response to drought stress. GUS staining has illustrated that the OfPIP2 promoter can drive GUS activity under drought conditions. The overexpression of OfPIP2 was found to enhance petal size by modulating epidermal cell dimensions in Petunia and tobacco. Moreover, this overexpression also bolstered drought tolerance, as evidenced by a reduction in stomatal aperture in both species. Furthermore, yeast one-hybrid (Y1H) and dual-luciferase (Dual-LUC) assays have indicated that the transcription factor OfMYB28 directly binds to the OfPIP2 promoter, thereby regulating its expression. Together, we speculated that a module of OfMYB28-OfPIP2 was not only involved in the enhancement of petal size but also conferred the improvement of drought tolerance in O. fragrans. These results contribute valuable insights into the molecular function of the OfPIP2 gene and lay a foundation for molecular breeding strategies in O. fragrans. [ABSTRACT FROM AUTHOR]

Key message: ARG6 and ARG10 pea accessions exhibited better tolerance to drought by keeping drought-associated attributes stable and higher, that is, stable chlorophyll content, high antioxidant activity, and the presence of polymorphic bands with stress-responsive EST-SSR markers. Each year, a significant portion of crops is lost due to various abiotic stresses, and even pea (Pisum sativum) crop growth and yield are severely affected by the challenges posed by drought stress. Drought is a critical factor that limits crop growth and development, and its impact is exacerbated by changes in the magnitude of climatic conditions. Drought induces oxidative stress in plants, leading to the accumulation of high concentrations of reactive oxygen species that damage cell structures and vital functioning of cells. The primary objective was to identify stress-tolerant plants by evaluating different morphological and biochemical attributes, such as biomass, chlorophyll content, relative water content, ascorbate peroxidase (APX), superoxide dismutase (SOD), and DPPH scavenging activity, as well as protein, proline, and phenolic content. Our study revealed that pea accessions (ARG6 and ARG10) were more resilient to drought stress as their chlorophyll, relative water, protein, and proline contents increased under drought conditions. Antioxidant enzymes, such as SOD, APX, and DPPH activities, also increased under drought stress in ARG10 and ARG6, suggesting that these accessions could bolster the antioxidant defense system in response to drought stress. Based on putative (cellular, biological, and metabolic) functions, ten EST-SSR primers were selected for the amplification study. Three EST-SSR primers, AUMP06_110, AUMP18_300, and AUMP31_250, were used for ARG6 and ARG10. Based on the correlation between the presence or absence of specific EST-SSR alleles, various physiological and morphological traits, and DPPH scavenging activity, both ARG10 and ARG6 demonstrated resistance to drought stress. [ABSTRACT FROM AUTHOR]

Background: Water deficit can seriously affect the growth, yield, and biochemical properties of plants; however, the application of nano‐iron chelate and arbuscular mycorrhizal fertilizers in water deficit has been considered one of the most promising methods to improve plant growth and enhance drought tolerance. Aims: This study aimed to investigate the effects of nano‐iron chelated (nFe) fertilizer and arbuscular mycorrhizal fungi (AMFs) on the growth, yield, root colonization, mycorrhizal dependency, water use efficiency (WUE), physio‐biochemical properties, and seed biochemical properties of Lallemantia iberica and Lallemantia royleana species under drought stress. Methods: A split‐factorial experiment was conducted using a randomized complete block design with three replications. The main plot consisted of three drought stress levels (according to the depletion of soil available water) of 30% (I1; without stress), 60% (I2; mild stress), and 90% (I3; severe stress). The subplots were the factorial combination of fertilizers (F) (without fertilizer, nano‐iron chelate [nFe], and AMFs) and plant species (S) of Lallemantia (L. iberica and L. royleana). Results: A decrease in the irrigation regime caused a reduction in growth, seed yield, WUE, chlorophyll content, nutrient uptake, seed oil, and mucilage content, as well as an increase in lipid peroxidation and hydrogen peroxide. Compared with nFe, AMF significantly increased root colonization by mycorrhizal fungi in both species across irrigation regimes. Furthermore, AMF inoculation enhanced nutrient uptake, mucilage, oil, and fatty acids by increasing the WUE. Higher mycorrhizal dependency in inoculated plants played an important role in increasing proline and antioxidant activities in the leaves of the host plant. The water stress and fertilization treatments resulted in the highest root colonization, mycorrhizal dependency, proline content, and antioxidant enzyme activities in L. royleana, as well as the highest WUE, accumulation of fatty acids, and nutrient uptake was observed in L. iberica. Interestingly, the mycorrhization potential of Lallemantia sp. is clearly defined. Conclusions: The results highlighted that AMFs can promote Lallemantia to increase seed mucilage and oil under water stress. Overall, we found that both Lallemantia species responded well to AMF inoculation under water deficit conditions, where nFe was found to be less effective. [ABSTRACT FROM AUTHOR]

Barley production is severely affected by drought caused by the unpredictable Mediterranean weather patterns, which include uneven rainfall and extreme temperatures. This leads to a decrease in crop yield. However, to tackle this issue, landraces and wild species are crucial sources of variation for stress adaptive traits. By incorporating these traits into improved varieties, we may see an increase in yield and stability under drought conditions. Seventy‐six quantitative traits loci (QTLs) identified traits were mapped using recombinant inbred lines (RIL) population Arta × Harmal‐2//Esp/1808‐4L, evaluated at six dry and semi‐dry areas over 3 years. The study investigated traits such as grain yield, biological yield, harvest index, kernel weight, seed per head, days to heading, kernel filling duration, growth vigour, growth habit, lodging and plant height. Numerous QTLs were discovered that are associated with various phenotypic traits related to grain yield, kernel yield, duration of filling period and days to heading. For areas with less than 250 mm/annum of rainfall, QTLs were identified on chromosome 2H for biological yield, days to heading, and kernel weight, on 1H for harvest index, and on 2H, 4H, and 5H for kernel weight. For semi‐dry areas with rainfall less than 450 mm, QTLs were found on chromosome 6H for grain yield, 2H and 5H for kernel weight, 1H and 6H for seed per head, and 2H for days to heading. Notably, these QTLs significantly explain more than 10% of phenotypic variation. The 2H chromosome was found to have the most important QTL and pleiotropic effect for yield and its components, such as kernel weight, days to heading, and biological yield. The cross Arta/Harmal was adapted, and mechanisms were developed to cope with drought stress, reflected by the significant and positive correlation of biological yield and harvest index with grain yield. Chromosomes 1H, 2H, 4H and 5H harbour more than 60% of mapped QTLs for dry areas. It is worth noting that the QTLs mentioned earlier, along with the kernel weight QTLs (QKW 1.5, QKW2.7b, QKW4.1, QKW6.7, QKW6.9), have consistently exhibited positive effects on crop yield in semi‐dry and dry areas, making them potential candidates for breeding drought‐tolerant crops. Genomic co‐localisation of the QTL for Arta/Harmal population suggested that selection for drought through linked markers can be an option for drought tolerance selection for barley in dry areas. [ABSTRACT FROM AUTHOR]