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Key Message: OsCactinpositively regulates drought tolerance in rice. OsCactin is regulated by OsTRAB1 and interacts with OsDi19 proteins to defend against drought stress. Drought stress significantly limits plant growth and production. Cactin, a CactinC_cactus domain-containing protein encoded by a highly conserved single-copy gene prevalent across the eukaryotic kingdom, is known to play diverse roles in fundamental biological processes. However, its function in rice drought tolerance remains poorly understood. In this study, with its overexpression and knockout rice lines in both a pot drought experiment and a PEG drought-simulation test, OsCactin was found to positively regulate rice drought tolerance during the rice seedling stage. The OsCactin-overexpressing lines presented high tolerance to drought stress, whereas the OsCactin-knockout plants were sensitive to drought stress. OsCactin was localized in the nucleus, and was predominantly expressed in the leaves and panicles at the seedling and booting stages, respectively. Furthermore, OsTRAB1, a drought-responsive TF of the bZIP family, binds to the promoter of OsCactin as a drought-responsive regulator. OsDi19 proteins, the Cys2/His2 (C2H2)-type zinc finger TFs from the drought-induced 19 family, interact with OsCactin both in vitro and in vivo. Our results provide new insights into the intricate mechanisms by which OsCactin regulates the rice drought stress response, which may contribute to the design of molecular breeding methods for rice., Competing Interests: Declarations Conflict of interest The authors declare no conflict of interest., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Key Message: MT mitigates chilling damage by enhancing antioxidant system and photosystem activities, and cold-responsive genes expression in cucumbers. H 2 O 2 may act as a downstream signaling molecule in the MT-induced chilling tolerance. Melatonin (MT) and hydrogen peroxide (H 2 O 2 ) are important endogenous signaling molecules that play multifaceted roles in plant responses to abiotic stress. However, the interactive mechanism by which MT and H 2 O 2 regulate chilling tolerance remains unclear. Here we found that MT exhibited a positive regulatory effect on the chilling tolerance of cucumbers, with an optimum concentration of 100 µM. MT markedly enhanced RBOH1 mRNA expression, activity and endogenous H 2 O 2 accumulation in cucumber seedlings. However, 1.0 mM H 2 O 2 had no significant effect on mRNA levels of TDC and ASMT, the key genes for MT synthesis, and endogenous MT content. Both MT and H 2 O 2 significantly decreased malondialdehyde (MDA), electrolyte leakage (EL) and chilling injury index (CI) by activating the antioxidant system, thereby alleviating chilling damage in cucumber seedlings. MT and H 2 O 2 improved photosynthetic carbon assimilation, which was primarily attributed to an increase in activity, mRNA expression, and protein levels of RuBPCase and RCA. Meanwhile, MT and H 2 O 2 induced the photoprotection for both PSII and PSI by enhancing the QA's electron transport capacity and elevating protein levels of the photosystems. Moreover, MT and H 2 O 2 significantly upregulated the expression of cold response genes. MT-induced chilling tolerance was attenuated by N', N'-dimethylthiourea (DMTU), a H 2 O 2 specific scavenger. Whereas, the MT synthesis inhibitor (p-chlorophenylalanine, p-CPA) did not influence H 2 O 2 -induced chilling tolerance. The positive regulation of MT on the antioxidant system, photosynthesis and cold response gene levels were significantly attenuated in RBOH1-RNAi plants compared with WT plants. These findings suggest that H 2 O 2 may functions as a downstream signaling molecule in MT-induced chilling tolerance in cucumber plants., Competing Interests: Declarations Conflict of interest The authors hereby affirm that they do not possess any conflicts of interest., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Lammas growth of trees means the additional growth of the shoot after the growth cessation and bud set in late summer. In temperate tree species, lammas growth occurs irregularly and is often regarded as abnormal, disturbed growth. In subtropical tree species, however, lammas growth is a prevalent phenomenon, possibly due to the prolonged occurrence of high temperatures in the autumn. The occurrence of lammas growth extends the growing season of trees, but its influence on subsequent dormancy phenomena and bud burst phenology remains largely unexplored. By comparing seedlings showing lammas growth with others not showing it, we carried out an experimental study of how lammas growth affects the bud burst phenology and the underlying dormancy phenomena under both ambient and controlled chilling, forcing and warming conditions in four subtropical tree species: Carya illinoinensis, Cinnamomum japonicum, Phoebe chekiangensis and Torreya grandis. With the exception of C. illinoinensis, lammas growth delayed bud burst in all the species under ambient conditions. In the chilling experiment, the delayed bud burst appeared to be due to higher minimum forcing requirement, higher dormancy depth, and in T. grandis, also due to lower chilling sensitivity in the lammas-growth seedlings than in the non-lammas-growth ones. However, a spring warming experiment showed that the sensitivity of bud burst to spring temperatures was higher in the lammas-growth seedlings than in the non-lammas-growth ones. Because of this, the difference between the two phenotypes in the timing of bud burst vanished with increasing warming. Our findings elucidate the significant impact of lammas growth on the dormancy dynamics of subtropical tree species, highlighting the necessity to better understand how the physiological phenomena causing lammas growth change the trees' subsequent environmental responses under changing climatic conditions., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Plants have developed various strategies to deal with abiotic stresses throughout their lifetimes. However, environmental stresses can have long-lasting effects, positively modifying plant physiological responses to subsequent stress episodes, a phenomenon known as preconditioning or stress memory. Intriguingly, this memory can even be transmitted to offspring, referred to as "inter- or transgenerational memory". Chenopodium quinoa is a pseudocereal that can withstand several abiotic stresses, including nitrogen (N) limitation. This research highlights the critical role of maternal N conditions in shaping the physiological and metabolic responses of their offspring. Mother quinoa plants (F0) were grown under High N (HN) or Low N (LN) conditions. LN F0 plants exhibited lower panicle biomass, net photosynthesis, and yield compared to HN F0 plants. Seeds from LN F0 retained proteins, reduced amino acids' levels, and increased lipids (such as PI 34:2), especially phosphatidylcholines, and their unsaturation level, which was associated with faster germination compared to HN F0 seeds. Offsprings seedlings (F1) grown under either HN or LN had similar proteins and amino acid proportions of their seeds. However, LN F0 LN F1 seedlings displayed significantly higher biomass and number of root tips. These changes were significantly correlated with transpiration, net photosynthesis, and stomatal conductance, as well as with starch content, suggesting higher CO 2 fixation at the whole plant level in LN F0 LN F1 plants. Our findings suggest that quinoa transmits maternal environmental stress information to its offspring, modulating their resilience. This work underscores the potential of utilizing maternal environmental conditions as a natural priming tool to enhance crop resilience against nutritional stress., (© 2024 Scandinavian Plant Physiology Society.)

Soil salinization, which severely limits crop yield and quality, has become a global environmental and resource issue. Melatonin plays an important role in plant responses to salt stress. Smooth bromegrass is an important forage with excellent feed value and is widely grown in northern and north-west China for pasture and sand binding. However, the physiological and molecular mechanisms underlying exogenous melatonin regulation of salt stress in smooth bromegrass are not clear. This study compared the phenotype, physiological, transcriptome, and metabolome profiles of two varieties with contrasting salt tolerance attributes under salt and melatonin treatment. After melatonin treatment, the catalase (CAT) and ascorbate peroxidase (APX) activity, proline content, actual photochemical efficiency (Y(II)), relative water content, and fresh weight above ground were significantly higher than under salt treatment, while relative conductivity, H 2 O 2 content, and Na + /K + ratio were significantly lower than salt treatment. The transcriptome and metabolite profiling analysis of smooth bromegrass seedlings treated without melatonin under salt stress identified the presence of 22522 differentially expressed genes (DEGs) and 862 differentially expressed metabolites (DEMs) in SS, 17809 DEGs and 812 DEMs in ST, while treated with melatonin under salt stress identified the presence of 7033 DEGs and 177 DEMs in SS, 2951 DEGs and 545 DEMs in ST. Furthermore, in response to salt stress, melatonin may be involved in regulating the correlation between DEGs and DEMs in flavonoid biosynthesis, proline biosynthesis, and melatonin biosynthesis. Moreover, melatonin participated in mediating melatonin biosynthesis pathways and affected the expression of ASMT in response to salt stress., (© 2024 Scandinavian Plant Physiology Society.)

Long-distance signals play a vital role in plant stress response. γ-aminobutyric acid (GABA) has been proposed to be a signal and protects crops against diverse stresses. However, whether GABA acts as a long-distance signal to plant response to stresses remains unknown. Here, we found that the GABA content in cucurbita rootstocks, especially figleaf gourd, was significantly higher than that in cucumber. Figleaf gourd rootstock obviously enhanced cold tolerance and GABA accumulation in roots, xylem sap and leaves of grafting cucumber seedlings. Conversely, GABA synthesis inhibitor 3-mercaptopropionic acid (3-MPA) irrigation was more effective than its foliar application in inhibiting grafting-induced cold tolerance. Moreover, fluorescence microscopy confirmed that GABA can be transported from root to shoot through the xylem when the roots of grafted seedlings were fed with fluorescein isothiocyatate-labeled GABA under normal and cold stress conditions. Importantly, 3-MPA irrigation attenuated grafting-induced cold tolerance, as revealed by a decline in the GABA accumulation, the transcripts of ICE1, CBF1 and COR47, the activities of the antioxidant enzymes, and an increase in stomatal aperture. Collectively, our findings strongly support that GABA functions as a novel long-distance signal in figleaf gourd rootstock-induced cold tolerance of grafted cucumber seedlings by modulating CBF-signalling pathways, antioxidant system and stomatal aperture, providing new evidence for long-distance signaling-mediated cold response of plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The widespread use of antibiotics in intensive animal husbandry, and the agricultural utilization of manure from such farms, imposes a significant burden on the environment. Consequently, the effects of antibiotics should be studied not only in animals and humans but also in all components of biocenoses and agrocenoses. In our study, we analyze the impact of four different concentrations of tetracycline present in soil (0, 5, 50, and 500 mg/kg of soil) on the growth and key photosynthesis parameters of pea seedlings: chlorophyll concentration, aminolevulinic acid concentration, aminolevulinic acid dehydrogenase activity, and ribulose bisphosphate carboxylase-oxygenase (RuBisCO) activity. At the lowest tetracycline concentration, chlorophyll content decreased by 13% compared to the control (0 tetracycline), while at the highest antibiotic concentration, it decreased by as much as 27%. Similarly, the decrease in aminolevulinic acid (a chlorophyll precursor) concentration was significant, amounting to 34%. However, the activity of the dehydrogenase enzyme, which consumes this precursor, decreased even more drastically by 51%, indicating significant disturbances in the light phase of photosynthesis. However, the activity of RuBisCO in pea plants subjected to tetracycline was even more severely affected, dropping by 58%, 69%, and 70% in soils with increasing concentrations of tetracycline. The reduction in enzyme activity could only partially be explained by a less pronounced decrease in the quantity of RuBisCO (large subunit) protein, which amounted to 6.5%, 11%, and 35% for tetracycline concentrations of 5, 50, and 500 mg/kg of soil, respectively., (© 2024. The Author(s).)

Soil salinization has been considered as a major environmental threat to plant growth. Different types of salt in saline soil have different effects on germination and seedling growth. Effect of NaCl on germination and seedling establishment in Suaeda liaotungensis have been reported, but its response to alkali stress remains unclear. Our results showed that brown seeds had higher germination rate, however, black seeds had higher germination recovery percentage under alkali stress. Na 2 CO 3 had stronger inhibitory effect on germination and seedling growth than NaHCO 3 . As the concentration of alkali stress increased, the ROS level of brown seeds gradually ascended, while that of black seeds decreased first and then ascended. MDA content of dimorphic seeds significantly increased under alkali stress. The trend of SOD, POD and CAT activity between dimorphic seeds was similar under the same type of alkali stress. Alkali stress enhanced proline content of dimorphic seeds, and dimorphic seeds in NaHCO 3 solution had higher proline content than Na 2 CO 3 solution. Moreover, radicle and shoot tolerance indexes of seedlings in NaHCO 3 solution were significantly higher than that of Na 2 CO 3 solution. Under strong alkali stress, seedlings in NaHCO 3 solution had significantly lower ROS level and MDA content as well as higher antioxidant enzyme activity than Na 2 CO 3 solution. This study comprehensively compared the morphological and physiological characteristics in germination and seedlings to better reveal the saline-alkali tolerance mechanisms in S. liaotungensis., (© 2024. The Author(s) under exclusive licence to The Botanical Society of Japan.)

Background: Drought stress markedly constrains plant growth and diminishes crop productivity. Strigolactones (SLs) exert a beneficial influence on plant resilience to drought conditions. Nevertheless, the specific function of SLs in modulating cotton's response to drought stress remains to be elucidated., Results: In this study, we assess the impact of exogenous SL (rac-GR24) administration at various concentrations (0, 1, 5, 10, 20 µM) on cotton growth during drought stress. The findings reveal that cotton seedlings treated with 5 µM exogenous SL exhibit optimal mitigation of growth suppression induced by drought stress. Treatment with 5 µM exogenous SL under drought stress conditions enhances drought tolerance in cotton seedlings by augmenting photosynthetic efficiency, facilitating stomatal closure, diminishing reactive oxygen species (ROS) generation, alleviating membrane lipid peroxidation, enhancing the activity of antioxidant enzymes, elevating the levels of osmoregulatory compounds, and upregulating the expression of drought-responsive genes. The suppression of cotton SL biosynthesis genes, MORE AXILLARY GROWTH 3 (GhMAX3) and GhMAX4b, impairs the drought tolerance of cotton. Conversely, overexpression of GhMAX3 and GhMAX4b in respective Arabidopsis mutants ameliorates the drought-sensitive phenotype in these mutants., Conclusion: These observations underscore that SLs significantly bolster cotton's resistance to drought stress., (© 2024. The Author(s).)

Sweet corn (Zea mays L.) var. Saccharata is a tropical and semitropical annual cereal with low germination, poor vigor, and weak seedling establishment in the soil. In order to enhance the physical properties of sweet corn and examine the effects of seed coating on the morphological, biochemical, and physiological characteristics of sweet corn seedlings under drought stress conditions, we conducted a factorial experiment in greenhouse conditions. Seed coating was carried out using a mixture of vermiculite (V), kaolin (K), and perlite (P) in a ratio of 3:1.5:2. The main factors of the greenhouse experiment comprised three levels of coating treatment (chitosan 0.5% + V10K2.5P5 (gr), NaAlg 1% + V10K2.5P5 (gr), and non-coated seeds as a control) along with drought stress at four levels (0, -0.3, -0.6, and -0.9 bar). In greenhouse conditions, the growth indexes of sweet corn seedlings were studied under increasing levels of drought stress. The results showed that as drought stress levels increased, certain growth indicators such as seedling emergence and seedling emergence rate, soluble protein, chlorophyll total content, nitrogen, and phosphorus content decreased. On the other hand, mean emergence, proline, potassium, soluble sugars, malondialdehyde, and hydrogen peroxide were increased. The study found that the highest seedling emergence percentage occurred in the coating treatment of chitosan 0.5% + V10K2.5P5 (gr) at all levels of drought stress. Overall, seed coating with the Chitosan 0.5% + V10K2.5P5 (gr) treatment improved the performance of sweet corn seeds and reduced the negative effects of drought stress by increasing seedling emergence and establishment., (© 2024. The Author(s).)

Key Message: A plant growth regulator, 5-aminolevulinic acid, enhanced the saline-alkali tolerance via photosynthetic, oxidative-reduction, and glutathione metabolism pathways in pepper seedlings. Saline-alkali stress is a prominent environmental problem, hindering growth and development of pepper. 5-Aminolevulinic acid (ALA) application effectively improves plant growth status under various abiotic stresses. Here, we evaluated morphological, physiological, and transcriptomic differences in saline-alkali-stressed pepper seedlings after ALA application to explore the impact of ALA on saline-alkali stress. The results indicated that saline-alkali stress inhibited plant growth, decreased biomass and photosynthesis, altered the osmolyte content and antioxidant system, and increased reactive oxygen species (ROS) accumulation and proline content in pepper seedlings. Conversely, the application of exogenous ALA alleviated this damage by increasing the photosynthetic rate, osmolyte content, antioxidant enzyme activity, and antioxidants, including superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase, and reducing glutathione to reduce ROS accumulation and malonaldehyde content. Moreover, the transcriptomic analysis revealed the differentially expressed genes were mainly associated with photosynthesis, oxidation-reduction process, and glutathione metabolism in saline-alkali stress + ALA treatment compared to saline-alkali treatment. Among them, the change in expression level in CaGST, CaGR, and CaGPX was close to the variation of corresponding enzyme activity. Collectively, our findings revealed the alleviating effect of ALA on saline-alkali stress in pepper seedlings, broadening the application of ALA and providing a feasible strategy for utilize saline-alkali soil., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Grazing livestock emits methane through rumen intestinal activity, however, its impact on plant growth in grassland while grazing still has not been explored in detail. Therefore, the study examined the effects of methane pulse spray (MPS), according to grazing intensity, at four grazing intensities (0, 3.6, 5.0, and 6.5 sheep·hm - 2 yr - 1 ) on seed germination and seedling growth of common vetch (Vicia sativa), while two irrigation rates (35 and 53 ml d - 1 ) were employed to simulate the precipitation., Results: The study revealed significant interactions between MPS and irrigation rate on seed germination and seedling growth parameters. Under moderate MPS intensities (0.74 and 1.04 mol m - 2 ), seed germination rate, potential, index, and vigor index improved, especially at higher irrigation rates (53 ml d - 1 ). Conversely, excessive MPS (1.33 mol m - 2 ) inhibited particularly at the germination rate and growth,. The seedling growth dynamics fitted a logistic model, with MPS advancing the rapid growth phase and increasing maximum growth rates., Conclusions: This study demonstrates that low to moderate levels of MPS from ruminants can promote seed germination and seedling growth of common vetch, while excessive MPS inhibits these processes. Irrigation enhances plant sensitivity to MPS, with wetter conditions (620 mm yr - 1 ) facilitating a more pronounced response. The findings introduce a new model elucidating plant responses to external perturbations, which can inform grazing management strategies in diverse ecosystems. In wetter regions, moderate grazing intensities may leverage MPS benefits, while arid regions require careful grazing regulation to maintain grassland-livestock balance., (© 2024. The Author(s).)

Temperature is an important limiting factor in the counter-seasonal cultivation of pepper. Currently, there are no studies on transcriptomic analysis of 'cold stress memory' in pepper. In this study, in order to understand the mechanism of 'cold stress memory' in pepper (Capsicum annuum L.), seedlings were subjected to the following treatments: normal temperature treatment (P0), the first cold treatment for 3 days (P3), the recovery temperature treatment for 3 days (R3), and another cold treatment for 3 days (RP3). The results showed that P3 plants wilted the most, RP3 the second and R3 the least. Leaf reactive oxygen species (ROS) and electrolyte leakage were the most in P3, the second in RP3 and the least in R3. In addition, RP3 had the highest accumulation of zeaxanthin, violaxanthin and β-cryptoxanthin, followed by P3, and R3 had the least. These results suggest that pepper seedlings are characterized by 'cold stress memory'. Transcriptomics was used to analyze the key genes and transcription factors involved in the biosynthesis of zeaxanthin, violaxanthin and β-cryptoxanthin during the formation of 'cold stress memory'. This study provides candidate genes and transcription factors for an in-depth study of the cold tolerance mechanism in pepper., (© 2024. The Author(s).)

Low temperature is one of the environmental factors that restrict the growth and geographical distribution of Brassica. To investigate the effects of exogenous calcium and calcium inhibitor on the ability of winter turnip rapeseed (Brassica rapa L.) to withstand low temperatures (4℃), we used a strong cold-resistant variety Longyou 7 (L7) and a weak cold-resistant variety Longyou 99 (L99) as the materials. The seedlings were treated with CaCl 2 (20 mmol·L -1 ) and calcium inhibitor LaCl 3 (10 mmol·L -1 ) at 0 h (CK), 6 h, 12 h, 24 h and 48 h after 4℃ treatments. Physiological characteristics, Ca 2+ flux and Ca 2+ concentration in roots after treatments were analyzed. Results illustrated that under 4℃ treatment, activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased by both CK and exogenous CaCl 2 treatments. Contents of soluble protein (SP) and proline (Pro) increased, while contents of malondialdehyde (MDA) decreased, resulting in reduced membrane lipid peroxidation. But enzyme activity decreased and MDA content increased following treatment with exogenous LaCl 3 . The rate of Ca 2+ flow showed a higher uptake in L7 roots compared with L99. L99 showed Ca 2+ efflux with a rate of 30.21 pmol‧cm -2 ‧s -1 , whereas L7 showed short efflux then returned to influx. Calcium ion content in roots decreased in both cultivars after CaCl 2 treatment. Results of RNA-seq revealed that genes were differentially expressed in response to low temperatures, hormones, photosystem II, chloroplasts, DNA replication, ribosomal RNA processing, and translation. This study found significant expression genes related to cellular signal transduction (MAPK signaling pathway) and material metabolism (nitrogen metabolism, glycerol ester metabolism).It was also analyzed by WGCNA that two modules had the strongest correlation with physiological indicators. Eight candidate genes were identified among MAPK signaling pathway and the two modules., (© 2024. The Author(s).)

Background: Cold is an important environmental limiting factor affecting plant yield and quality. Capsicum (chili pepper), a tropical and subtropical vegetable crop, is extremely sensitive to cold. Although H 2 S is an important signaling regulator in the responses of plant growth and development to abiotic stress, few studies have examined its effects on cold-sensitive capsicum varieties. Through biotechnology methods to enhance the cold resistance of peppers, to provide some reference for pepper breeding, investigated molecular regulation by H 2 S of responses to cold stress in cold-sensitive capsicum plants, via physiological and transcriptomic analyses., Results: In capsicum seedlings, exogenous H 2 S enhanced relative electrical conductivity (REC) and levels of malondialdehyde (MDA) under cold stress, maintained membrane integrity, increased the activity of enzymatic and non-enzymatic antioxidants, balanced reactive oxygen species levels (O 2 ·- and H 2 O 2 ), and improved photosynthesis, mitigating the damage caused by cold. In addition, 416 differentially expressed genes (DEGs) were involved in the response to cold stress after H 2 S treatment. These DEGs were mainly enriched in the ascorbate-glutathione and starch-sucrose metabolic pathways and plant hormone signal-transduction pathways. Exogenous H 2 S altered the expression of key enzyme-encoding genes such as GST, APX, and MDHAR in the ascorbate-glutathione metabolism pathway, as well as that of regulatory genes for stimulatory hormones (auxin, cytokinins, and gibberellins) and inhibitory hormones (including jasmonate and salicylic acid) in the plant hormone signal-transduction pathway, helping to maintain the energy supply and intracellular metabolic stability under cold stress., Conclusions: These findings reveal that exogenous H 2 S improves cold tolerance in cold-sensitive capsicum plants, elucidating the molecular mechanisms underlying its responses to cold stress. This study provides a theoretical basis for exploring and improving cold tolerance in capsicum plants., (© 2024. The Author(s).)

Eggplant (Solanum melongena) is moderately sensitive to salinity. Seed priming and exogenous supplementation are technique that enhances germination, growth, and crop yield by overcoming salt stress. Therefore, this study was designed to understand the role of seed priming and copper (Cu) supplementation in modulating salt tolerance in eggplant. When exposed to salt stress, eggplant seedlings showed significantly higher Na +  content, an increased Na/K ratio, prolonged mean germination time, higher relative water loss, more days to flower bud initiation and first flowering, along with decreased germination rate, growth factors, water content, photosynthetic pigments, ionic contents (K + , Ca 2+ , Mg 2+ ), and yield. The results demonstrated that the germination rate, final germination percentage, germination index, germination energy, and seed vigor index significantly improved, while the mean germination time decreased in Cu-primed seeds. The results also revealed that Cu supplementations increased seedling traits, leaf water content, photosynthetic pigment contents, ionic contents (K + , Ca 2+ , and Mg 2+ ), and yield while decreasing the contents of Na + , and Na/K ratio, mean germination time, relative water loss, days to flower bud initiation, and days to 1st flowering under salt stress. Germination of seeds, seedlings growth traits, plant water status, plant pigments, yield, and ionic contents with the NaCl and Cu treatments were found to substantially interact with each other according to both hierarchical clustering and PCA. Overall, Cu seed priming and exogenous supplementation emerged as a promising strategy to enhance salt tolerance and promote germination, growth, and yield by regulating water status, photosynthetic pigments, and ion homeostasis in eggplant seedlings under NaCl stress. These findings provide valuable insights into the mechanisms of Cu-mediated stress alleviation in eggplant, with implications for sustainable crop production in saline environments., (© 2024. The Author(s).)

Lowland northern white-cedar (Thuja occidentalis L.) forests are increasingly exposed to extreme droughts and floods that cause tree mortality. However, it is not clear the extent to which these events may differentially affect regeneration of cedar and its increasingly common associate, balsam fir (Abies balsamea (L.) Mill.). To test this, we measured how seedlings of cedar and fir were able to avoid, resist and recover from experimental drought and flood treatments of different lengths (8 to 66 days). Overall, we found that cedar exhibited a strategy of stress resistance and growth recovery (resilience) from moderate drought and flood stress. Fir, on the other hand, appears to be adapted to avoid drought and flood stress and exhibited overall lower growth resilience. In drought treatments, we found evidence of different stomatal behaviors. Cedar used available water quickly and therefore experienced more drought stress than fir, but cedar was able to survive at water potentials > 3 MPa below key hydraulic thresholds. On the other hand, fir employed a more conservative water-use strategy and therefore avoided extremely low water potential. In response to flood treatments, cedar survival was higher and only reached 50% if exposed to 23.1 days of flooding in contrast to only 7.4 days to reach 50% mortality for fir. In both droughts and floods, many stressed cedar were able to maintain partially brown canopies and often survived the stress, albeit with reduced growth, suggesting a strategy of resistance and resilience. In contrast, fir that experienced drought or flood stress had a threshold-type responses and they either had full live canopies with little effect on growth or they died suggesting reliance on a strategy of drought avoidance. Combined with increasingly variable precipitation regimes, seasonal flooding and complex microtopography that can provide safe sites in these forests, these results inform conservation and management of lowland cedar stands., (Published by Oxford University Press 2024.)

The current simple and crude facilities make melon production more susceptible to cold stress during off-season cultivation in China. The ABA signalling pathway is an important target for breeding cold-tolerant melon. Cold-tolerant No. 330 and cold-sensitive No. 410 oriental melon genotypes were used to analyse the relationship between ABA and cold tolerance. 12 CmPYLs, ABA receptors, were identified from the melon genome database according to sequence alignment and phylogenetic analysis. Gene function of CmPYL6 in cold tolerance was analysed using VIGS in No. 330 and overexpression in Arabidopsis WT. A total of 12 CmPYL members contain the representative domain and conserved sites. Under cold treatment, No.330 seedlings had lower electrolyte leakage and MDA content, higher ABA content and CmPYL6 expression than seedlings of No. 410. Exogenous application of ABA upregulated expression of CmPYL6 and enhanced cold tolerance of both genotypes, while inhibiting ABA accumulation reduced expression of CmPYL6 and cold tolerance of both genotypes. CmPYL6-silenced No. 330 seedlings had reduced cold tolerance, increased electrolyte leakage and MDA content as well as limited proline and soluble sugar content, while CmPYL6 overexpressed transgenic Arabidopsis plants had enhanced cold tolerance, with limited electrolyte leakage and MDA content, as well as increased proline and soluble sugar content. The CmPYL6 gene is probably an important ABA receptor in regulating cold tolerance of oriental melon. Our study provides a direction for improving breeding of cold tolerance of oriental melon., (© 2024 The Author(s). Plant Biology published by John Wiley & Sons Ltd on behalf of German Society for Plant Sciences, Royal Botanical Society of the Netherlands.)

We monitored leaf production in seedlings, trunkless juvenile, immature, and mature male and female plants of the dioecious palm, Lodoicea maldivica, and studied how internode length changed with trunk height. The fieldwork was conducted in closed forest on Praslin Island and degraded forest on Curieuse Island. Data on numbers of leaves produced and rates of leaf production were used to estimate plant age. On Praslin, the interval between successive leaves increased from 0.47/0.52 years in male/female plants to 4.2 years in seedlings, and on Curieuse from 0.41/0.49 to 2.3 years. Estimated leaf lifespan was 6.4-6.8 years in mature palms and much longer in seedlings and juveniles. On Praslin, internode length increased from the base of the trunk to a mean of 14 cm at leaf 21, before declining to 2.75 cm above leaf 100. Mean internode length of the smaller palms on Curieuse was 1.9 cm and varied little with height. Plants at the same development stage varied widely in age. On Praslin, median time to maturity was 77 (range: 32-209) and on Curieuse 83 (31-191) years. The tallest palms on Praslin (28.4 m trunk height) and Curieuse (8 m) were estimated at 442 and 232 years old, respectively. The ageing method was used to interpret height data of different populations. All showed a marked decline in regeneration in the 19th or early 20th centuries, probably caused by fires. We conclude that slow growth makes this species very vulnerable to disturbance, especially from fire., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

The rare and threatened Heliosciadium repens grows in moist grasslands and has a distinct life cycle. Plants reproduce both clonally, although ramets tend to be short-lived, and sexually, with seeds that can form a persistent soil seed bank. The germination requirements of H. repens were investigated, yielding important information for its habitat management and conservation. We examined the soil seed bank in three populations and carried out germination experiments and embryo growth measurements with fresh seeds in laboratory, greenhouse and outdoor conditions. We also investigated the effects of storage and burial of seeds. H. repens formed a long-term persistent (>6 years) soil seed bank with very pronounced primary dormancy, but no secondary dormancy or dormancy cycles. Seeds can germinate throughout the growing season when temperatures are sufficiently high. Embryo growth and seed germination are triggered by light and, to a lesser extent, daily temperature fluctuations. Seeds of H. repens seem to have developed a unique germination syndrome with several strategies to remain dormant in the soil until optimal conditions are present for seedling establishment and survival. Both sexual reproduction and seed bank formation are crucial for the long-term survival of the populations., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Mediterranean coastal cliffs are reservoirs of plant biodiversity, hosting vulnerable plant species particularly exposed to the risk of local extinction due to extreme abiotic conditions and climate changes. Therefore, studies aiming to understand the tolerance of cliff plant species to abiotic stresses are important to predict their long-time persistence or to highlight inherent threats. We used an integrative approach including anatomical, physiological and phenotypic analyses on (a) seeds, (b) cotyledons of seedlings; and (c) young plants to assess whether the cliff species Brassica incana, can tolerate exposure to different seawater (SW: 25%, 50% and 100%) concentrations during the early stages of its life cycle. Seeds could germinate when exposed to up to 50% SW. Seeds did not germinate in 100% SW, but could resume germination after washing with freshwater. Seed germination rate also decreased with increasing SW concentration. Exposure to SW decreased stomatal size and stomatal index of cotyledons and caused long-lasting and severe damage to the photochemical reactions of photosynthesis. Photochemistry was also sensitive to SW in young plants, but the effect was lower than in cotyledons. This may involve a remodulation of chloroplast dimensions and activation of cellular metabolism. However, photochemical reactions limited photosynthesis at100% SW even after recovery from SW exposure. Our data show that B. incana has strong tolerance to seawater and shows clear signs of halophytic adaptation. Whilst seeds and juvenile plants are able to withstand SW, the seedling stage appears to be more sensitive., (© 2024 The Author(s). Plant Biology published by John Wiley & Sons Ltd on behalf of German Society for Plant Sciences, Royal Botanical Society of the Netherlands.)

Changes in rainfall patterns are important environmental factors affecting plant growth, especially when larger precipitation events and prolonged drought periods occur in subtropical regions. There are many studies on how drought reduces plant biomass through drought-sensitive functional traits, but how excess water affects plant growth and ecophysiology is still poorly understood. Therefore, a greenhouse experiment was conducted on Schima superba (Theaceae), a dominant tree species in subtropical forests and commonly used in forestry, in a closed chamber under control (25% soil water content (SWC) as in local forests), drought stress (D, 15% SWC) and moisture stress (W, 35% SWC). Plant growth and ecophysiological traits related to morphology, leaf gas exchange, water potential and structural traits were measured. Compared to control, S. suberba under dry conditions significantly decreased its aboveground biomass, photosynthetic rate (A), leaf water potential and nitrogen use efficiency, but increased intrinsic water use efficiency, root to shoot ratio and specific root length. S. superba under wet conditions also significantly decreased its total biomass, aboveground biomass and specific root length, while W had no effect on A and leaf water potential. Our results indicate that S. superba shows a decrease in carbon gain under drought stress, but less response under wet conditions. This emphasizes the need to consider the strength and frequency of rainfall pattern changes in future studies because rainfall may either alleviate or intensify the effects of drought stress depending on the moisture level, thus suitable water conditions is important for better management of this tree species in subtropical China., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The growth and yield of rapeseed are significantly hampered by salt stress. Indole-3-butyric Acid Potassium Salt (IBA-K) has been found to alleviate the impact of salt stress on plant growth. However, the regulatory effect of IBA-K dipping on salt-stressed rapeseed remains unclear. To explore the implications of IBA-K on the growth and development of rapeseed during the seedling stage, we conducted potting experiments using the Huayouza 62 variety. Five different concentrations of IBA-K for seed soaking (0, 10, 20, 40, 80 mg·L - 1 ) were tested. The promotional impact of IBA-K on rapeseed demonstrated an initial increase followed by a decline, reaching a peak at 20 mg·L - 1 . Therefore, 20 mg·L - 1 was determined as the optimal concentration for subsequent experiments. To further understand the mechanism of IBA-K's action on salt-stressed rapeseed seedlings, we utilized the moderately salt-resistant cabbage rapeseed variety Huayouza 158R and the highly salt-resistant Huayouza 62 as specimens. The investigation focused on their response and repair mechanisms under 150 mmol·L - 1 NaCl stress. The findings demonstrated that compared with the sole NaCl stress, the 20 mg·L - 1 IBA-K seed soaking treatment under salt stress significantly enhanced the plant height, stem diameter, and leaf area of both rapeseed varieties. It also led to greater biomass accumulation, increased chlorophyll content, and improved photosynthetic efficiency in rapeseed. Furthermore, this treatment bolstered the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), while significantly reducing the levels of electrolyte leakage (EL) and malondialdehyde (MDA). Consequently, it alleviated the membrane lipid peroxidation damage induced by NaCl stress, enhanced the accumulation of soluble proteins, maintained cellular osmotic pressure, and effectively mitigated the adverse effects of NaCl stress on rapeseed., (© 2024. The Author(s).)

Background: The growth and yield of pepper, a typical temperature-loving vegetable, are limited by low-temperature environments. Using low-temperature sensitive 'Hangjiao No. 4' (Capsicum annuum L.) as experimental material, this study analyzed the changes in plant growth and photosynthesis under different treatments: normal control (NT), low-temperature stress alone (LT), low-temperature stress in strigolactone pretreated plants (SL_LT), and low-temperature stress in strigolactone biosynthesis inhibitor pretreated plants (Tis_LT)., Results: SL pretreatment increased the net photosynthetic rate (Pn) and PSII actual photochemical efficiency (φPSII), reducing the inhibition of LT on the growth of pepper by 17.44% (dry weight of shoot). Due to promoting the accumulation of carotenoids, such as lutein, and the de-epoxidation of the xanthophyll cycle [(Z + A)/(Z + A + V)] by strigolactone after long-term low-temperature stress (120 h), non-photochemical quenching (NPQ) of pepper was increased to reduce the excess excitation energy [(1-qP)/NPQ] and the photoinhibition degree (Fv/Fm) of pepper seedlings under long-term low-temperature stress was alleviated. Twelve cDNA libraries were constructed from pepper leaves by transcriptome sequencing. There were 8776 differentially expressed genes (DEGs), including 4473 (51.0%) upregulated and 4303 (49.0%) downregulated genes. Gene ontology pathway annotation showed that based on LT, the DEGs of SL_LT and Tis_LT were significantly enriched in the cellular component, which is mainly related to the photosystem and thylakoids. Further analysis of the porphyrin and chlorophyll biosynthesis, carotenoid biosynthesis, photosynthesis-antenna protein, and photosynthetic metabolic pathways and the Calvin cycle under low-temperature stress highlighted 18, 15, 21, 29, and 31 DEGs for further study, which were almost all highly expressed under SL_LT treatment and moderately expressed under LT treatment, whereas Tis_LT showed low expression., Conclusion: The positive regulatory effect of SLs on the low-temperature tolerance of pepper seedlings was confirmed. This study provided new insights for the development of temperature-tolerant pepper lines through breeding programs., (© 2024. The Author(s).)

Raffinose mitigates plant heat, drought, and cold stresses; however, whether raffinose contributes to plant waterlogging tolerance is unknown. The maize raffinose synthase mutant zmrafs-1 had seedlings that lack raffinose, generated fewer and shorter adventitious roots, and were more sensitive to waterlogging stress, while overexpression of the raffinose synthase gene, ZmRAFS, increased raffinose content, stimulated adventitious root formation, and enhanced waterlogging tolerance of maize seedlings. Transcriptome analysis of null segregant seedlings compared with zmrafs-1, particularly when waterlogged, revealed that the expression of genes related to galactose metabolism and the auxin biosynthetic pathway were up-regulated by raffinose. Additionally, indole-3-acetic acid content was significantly decreased in zmrafs-1 seedlings and increased in ZmRAFS-overexpressing seedlings. Inhibition of the hydrolysis of raffinose by 1-deoxygalactonojirimycin decreased the waterlogging tolerance of maize seedlings, the expression of genes encoding proteins related to auxin transport-related genes, and the indole-3-acetic acid level in the seedlings, indicating that the hydrolysis of raffinose is necessary for maize waterlogging tolerance. These data demonstrate that raffinose catabolism stimulates adventitious root formation via the auxin signaling pathway to enhance maize waterlogging tolerance., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Euphorbia resinifera O. Berg is a prickly, leafless and succulent, Moroccan endemic shrub. Field data indicate that the plant faces many challenges related to its natural regeneration and its gradual decline that can lead to a probability of extinction, at least in some areas. Successful seed germination and survival of E. resinifera seedlings during the dry period is one of the main obstacles encountered in establishing natural seedlings. With this in mind, 3080 seeds of two morphotypes of E. resinifera (M1 and M2) were harvested in the Atlas of Beni Mellal to study their germinative potential and determine suitable conditions for growth and development of the seedlings. In the laboratory, five temperatures (10 °, 15 °C, 18 °C, 25 °C, and 35 °C) and two photoperiods (12 h light/12 h dark and 24 h dark) were tested. Whereas in field research, two factors were considered: the availability of water and the type of substrate (clay, peat, and limestone). Results show a maximum germination rate of around 52% for M2 at 15 °C and 48% for M1 at 18 °C. The Monitoring of plant seedling establishment and growth revealed a high vulnerability to prolonged periods of drought. However, consolidated soil is more conducive to seedling establishment. For this species, it is therefore essential to conserve the habitat within the karst geosystem. Furthermore, the variability of this species' morphotypes and their growth form architecture shows a tendency to favor the dwarf, cushion-shaped morphotype, which is the most widespread in the study area.

Casuarina equisetifolia trees are used as windbreaks in subtropical and tropical coastal zones, while C. equisetifolia windbreak forests can be degraded by seawater atomization (SA) and seawater encroachment (SE). To investigate the mechanisms underlying the response of C. equisetifolia to SA and SE stress, the transcriptome and metabolome of C. equisetifolia seedlings treated with control, SA, and SE treatments were analyzed. We identified 737, 3232, 3138, and 3899 differentially expressed genes (SA and SE for 2 and 24 h), and 46, 66, 62, and 65 differentially accumulated metabolites (SA and SE for 12 and 24 h). The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that SA and SE stress significantly altered the expression of genes related to plant hormone signal transduction, plant-pathogen interaction, and starch and sucrose metabolism pathways. The accumulation of metabolites associated with the biosynthetic pathways of phenylpropanoid and amino acids, as well as starch and sucrose metabolism, and glycolysis/gluconeogenesis were significantly altered in C. equisetifolia subjected to SA and SE stress. In conclusion, C. equisetifolia responds to SA and SE stress by regulating plant hormone signal transduction, plant-pathogen interaction, biosynthesis of phenylpropanoid and amino acids, starch and sucrose metabolism, and glycolysis/gluconeogenesis pathways. Compared with SA stress, C. equisetifolia had a stronger perception and response to SE stress, which required more genes and metabolites to be regulated. This study enhances our understandings of how C. equisetifolia responds to two types of seawater stresses at transcriptional and metabolic levels. It also offers a theoretical framework for effective coastal vegetation management in tropical and subtropical regions., (© 2024. The Author(s).)

In breeding programs, stress memory in plants can develop drought stress tolerance. Memory stress, as an approach, can keep stress data by activating tolerance mechanisms. This research was conducted to evaluate some physiologically effective mechanisms in inducing memory drought stress in the seeds that were exposed to water stress three times in four treatments including rainfed, 33%, 66%, and 100% of field capacity (FC). After the production of the seeds, the third-generation seeds were placed under different irrigation treatments, seed and seedling traits, starch to carbohydrate ratio in seed, protein concentration and glutathione reductase were investigatied in a factorial format based on a randomized complete block design with three replications. Results showed that percentage of changes from the lowest to the highest value for traits including seed vigor, seed endosperm weight, seed coat weight, accelerated aging, cold test, seedling biomass and seedling length were 25, 37, 65, 65, 55, 77, 55, 65 and 79, respectively and germination uniformity was 3.9 times higher than the lowest amount. According to the deterioration percentage, seed vigor and the percentage of seed germination in cold test data, it can be reported that seed production by 100% FC was not appropriate for rainfed plots. However, considering the the appropriate results in the percentage of germination for a cold test, germination uniformity percentage, and the lowest accelerated aging seeds, seed production under the rainfed conditions with 33% FC watering can be recommended. In-silico analysis was coducted on Glutathione reductase (GR) enzymes in Gossypium hirsutum. It is clear that GR has a Redox-active site and NADPH binding, and it interacts with Glutathione S transferase (GST). So, memory drought stress through inducing physiological drought tolerance mechanisms such as starch-to-carbohydrate ratio and GR can determine the suitable pattern for seed production for rainfed and low rainfall regions in a breeding program. Our study thus illustrated that seed reprduction under 33% FC equipped cotton with the tolerance against under draught stress from the seedling stage. This process is done through activating glutathione reductase and balancing the ratio of starch to carbohydrates concentration., (© 2024. The Author(s).)

Drought is a significant global issue affecting agricultural production, and the utilization of beneficial rhizosphere microorganisms is one of the effective ways to increase the productivity of crops and forest under drought. In this study, we characterized a novel growth-promoting dark septate endophytes (DSE) fungus R16 (Dothideomycetes sp.) derived from blueberry roots. Hyphae or microsclerotia were visible within the epidermal or cortical cells of R16-colonized blueberry roots, which was consistent with the typical characteristics of DSE fungi. Inoculation with R16 promoted the growth of blueberry seedlings, and the advantage over the control group was more significant under PEG-induced drought. Comparison of physiological indicators related to drought resistance between the inoculated and control groups was performed on the potted blueberry plants, including the chlorophyll content, net photosynthetic rate, root activities, malondialdehyde and H2O2 content, which indicated that R16 colonization mitigated drought injury in blueberry plants. We further analyzed the effects of R16 on phytohormones and non-structural carbohydrates (NSCs) to explore the mechanism of increased drought tolerance by R16 in blueberry seedlings. The results showed that except for the gibberellin content, indole-3-acetic acid, zeatin and abscisic acid varied significantly between the inoculated and control groups. Sucrose phosphate synthase and sorbitol-6-phosphate dehydrogenase activities in mature leaves, the key enzymes responsible for sucrose and sorbitol synthesis, respectively, as well as sorbitol dehydrogenase, sucrose synthase, cell wall invertase, hexokinase and fructokinase in roots, the key enzymes involved in the NSCs metabolism, showed significant differences between the inoculated and control groups before and after drought treatment. These results suggested that the positive effects of R16 colonization on the drought tolerance of blueberry seedlings are partially attributable to the regulation of phytohormone and sugar metabolism. This study provided valuable information for the research on the interaction between DSE fungi and host plants as well as the application of DSE preparations in agriculture., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Climate change is raising concerns about how forests will respond to extreme droughts, heat waves and their co-occurrence. In this greenhouse study, we tested how carbon and water relations relate to seedling growth and mortality of northeastern US trees during and after extreme drought, warming, and combined drought and warming. We compared the response of our focal species red spruce (Picea rubens Sarg.) with a common associate (paper birch, Betula papyrifera Marsh.) and a species expected to increase abundance in this region with climate change (northern red oak, Quercus rubra L.). We tracked growth and mortality, photosynthesis and water use of 216 seedlings of these species through a treatment and a recovery year. Each red spruce seedling was planted in containers either alone or with another seedling to simulate potential competition, and the seedlings were exposed to combinations of drought (irrigated, 15-d 'short' or 30-d 'long') and temperature (ambient or 16 days at +3.5 °C daily maximum) treatments. We found dominant effects of the drought reducing photosynthesis, midday water potential, and growth of spruce and birch, but that oak showed considerable resistance to drought stress. The effects of planting seedlings together were moderate and likely due to competition for limited water. Despite high temperatures reducing photosynthesis for all species, the warming imposed in this study minorly impacted growth only for oak in the recovery year. Overall, we found that the diverse water-use strategies employed by the species in our study related to their growth and recovery following drought stress. This study provides physiological evidence to support the prediction that native species to this region like red spruce and paper birch are susceptible to future climate extremes that may favor other species like northern red oak, leading to potential impacts on tree community dynamics under climate change., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

To address salinity stress in plants in an eco-friendly manner, this study investigated the potential effects of salinity-resistant bacteria isolated from saline agricultural soils on the growth of cucumber (Cucumis sativus, cv. Royal) seedlings. A greenhouse factorial experiment was conducted based on a completely randomized design (CRD) with two factors, salinity at four levels and five bacterial treatments, with three replications (n = 3). Initially, fifty bacterial isolates were screened for their salinity and drought tolerance, phosphate solubilization activity, along with production of auxin, siderophore and hydrogen cyanide. Isolates K4, K14, K15, and C8 exhibited the highest resistance to salinity and drought stresses in vitro. Isolates C8 and K15 demonstrated the highest auxin production capacity, generating 2.95 and 2.87 µg mL - 1 , respectively, and also exhibited significant siderophore production capacities (by 14% and 11%). Additionally, isolates C8 and K14 displayed greater phosphate solubilization activities, by 184.64 and 122.11 µg mL - 1 , respectively. The statistical analysis revealed that the selected four potent isolates significantly enhanced all growth parameters of cucumber plants grown under salinity stress conditions for six weeks. Plant height increased by 41%, fresh and dry weights by 35% and 7%, respectively, and the leaf area index by 85%. The most effective isolate, C8, was identified as Bacillus subtilis based on the 16 S rDNA amplicon sequencing. This study demonstrated that inoculating cucumber seedlings with halotolerant bacterial isolates, such as C8 (Bacillus subtilis), possessing substantial plant growth-promoting properties significantly alleviated salinity stress by enhancing plant growth parameters. These findings suggest a promising eco-friendly strategy for improving crop productivity in saline agricultural environments., (© 2024. The Author(s).)

Plant senescence is a highly regulated developmental program crucial for nutrient reallocation and stress adaptation in response to developmental and environmental cues. Stress-induced and age-dependent natural senescence share both overlapping and distinct molecular responses and regulatory schemes. Previously, we have utilized a carbon-deprivation (C-deprivation) senescence assay using Arabidopsis (Arabidopsis thaliana) seedlings to investigate senescence regulation. Here we conducted a comprehensive time-resolved transcriptomic analysis of Arabidopsis wild type seedlings subjected to C-deprivation treatment at multiple time points, unveiling substantial temporal changes and distinct gene expression patterns. Moreover, we identified ALTERED MERISTEM PROGRAM 1 (AMP1), encoding an endoplasmic reticulum protein, as a potential regulator of senescence based on its expression profile. By characterizing loss-of-function alleles and overexpression lines of AMP1, we confirmed its role as a negative regulator of plant senescence. Genetic analyses further revealed a synergistic interaction between AMP1 and the autophagy pathway in regulating senescence. Additionally, we discovered a functional association between AMP1 and the endosome-localized ABNORMAL SHOOT3 (ABS3)-mediated senescence pathway and positioned key senescence-promoting transcription factors downstream of AMP1. Overall, our findings shed light on the molecular intricacies of transcriptome reprogramming during C-deprivation-induced senescence and the functional interplay among endomembrane compartments in controlling plant senescence., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Waterlogging stress, particularly during seed germination, significantly affects plant growth and development. However, the physiological and molecular mechanisms underlying waterlogging stress responses during rapeseed germination remain unclear. In this study, two rapeseed cultivars, Xiangzayou518 (waterlogging-sensitive) and Dadi199 (waterlogging-tolerant), were used to explore the physiological mechanisms underlying rapeseed response to waterlogging stress during germination. Our results showed that waterlogging significantly decreased the emergence percentage and seedling growth rate. During the radicle elongation period (from 48 to 96 h post-germination), the most sensitive period to waterlogging during germination, sugar content, and glycolysis efficiency were significantly decreased, but anaerobic fermentation was enhanced. In tolerant cultivars, when the energy supply was insufficient, the conversion efficiency of lipids into sugar increased, and the activities of isocitrate lyase, malate synthase, and fructose-1, 6-diphosphatase were enhanced by 11.63, 19.06, and 20.37%, respectively, at 72 h post-germination under waterlogging stress. Transcriptome data showed that the differentially expressed genes were significantly enriched in glucose and lipid metabolism pathways when comparing waterlogged stress and normal conditions. These results indicate that waterlogging affects seed germination in rapeseed by inhibiting carbohydrate metabolism, and the conversion capacity of lipids into sugar under waterlogging stress was stronger in tolerant cultivars than in sensitive cultivars, thus rescuing the insufficient energy supply in seed germination and seedling growth. This study reveals the physiological mechanism of rapeseed response to waterlogging stress during seed germination and provides a valuable reference for improving waterlogging tolerance., (© 2024 Scandinavian Plant Physiology Society. Published by John Wiley & Sons Ltd.)

The efficient conversion of tissues into reproductive success is a crucial aspect affecting the evolution of life histories. Masting, the interannually variable and synchronous seed production in perennial plants, is a strategy that can enhance reproductive efficiency by mitigating seed predation and pollen limitation. However, evaluating benefits is insufficient to establish whether efficiency has improved, as such assessments neglect the associated costs of masting, particularly during the critical seed-to-seedling stage. We conducted a parentage analysis of seedlings and adults in a population of 209 Sorbus aucuparia trees, monitored over 23 years, providing pioneering documentation of the effects of masting on the fitness of individual trees beyond the seed stage. Our results show high costs of interannual variation that can be mitigated by high synchrony and reveal the existence of phenotypes that appear to reap the benefits of masting while avoiding its costs through regular reproduction., (© 2024 John Wiley & Sons Ltd.)

Lead (Pb) exposure can induce molecular changes in plants, disrupt metabolites, and impact plant growth. Therefore, it is essential to comprehend the molecular mechanisms involved in Pb tolerance in plants to evaluate the long-term environmental consequences of Pb exposure. This research focused on maize as the test subject to study variations in biomass, root traits, genes, and metabolites under hydroponic conditions under Pb conditions. The findings indicate that high Pb stress significantly disrupts plant growth and development, leading to a reduction in catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) activities by 17.12, 5.78, and 19.38%, respectively. Conversely, Pb stress led to increase malondialdehyde (MDA) contents, ultimately impacting the growth of maize. The non-targeted metabolomics analysis identified 393 metabolites categorized into 12 groups, primarily consisting of organic acids and derivatives, organ heterocyclic compounds, lipids and lipid-like molecules and benzenoids. Further analysis indicated that Pb stress induced an accumulation of 174 metabolites mainly enriched in seven metabolic pathways, for example phenylpropanoid biosynthesis and flavonoid biosynthesis. Transcriptome analysis revealed 1933 shared differentially expressed genes (DEGs), with 1356 upregulated and 577 downregulated genes across all Pb treatments. Additionally, an integrated analysis identified several DEGs and differentially accumulated metabolites (DAMs), including peroxidase, alpha-trehalose, and D-glucose 6-phosphate, which were linked to cell wall biosynthesis. These findings imply the significance of this pathway in Pb detoxification. This comprehensive investigation, employing multiple methodologies, provides a detailed molecular-level insight into maize's response to Pb stress., (© 2024 Scandinavian Plant Physiology Society.)

Here, we elucidate the interaction between IAA and melatonin (MT) in response to chilling in cucumber. The results showed that chilling stress induced the increase of endogenous MT and IAA, and the application of MT promoted the synthesis of IAA, while IAA could not affect endogenous MT content under chilling stress. Moreover, MT and IAA application both remarkably increased the chilling tolerance of cucumber seedlings in terms of lower contents of MDA and ROS, higher mRNA abundance of cold response genes, net photosynthetic rate (P n ), maximum regeneration rate of ribulose-1,5-diphosphate (J max ), Rubisco maximum carboxylation efficiency (V cmax ), the activities and gene expression of RCA and Rubisco, as well as the content of active P700 (I/I 0 ) and photosynthetic electron transport, compared with the plants in H 2 O treatment. Further analysis revealed that the inhibition of IAA transportation significantly reduced the chilling tolerance induced by MT, whereas the inhibition of endogenous MT did not affect the chilling tolerance induced by IAA. Meanwhile, we found that overexpression of the MT biosynthesis gene CsASMT increased the chilling tolerance, which was blocked by inhibition of endogenous IAA, and the silence of IAA biosynthesis gene CsYUCCA10 decreased the chilling tolerance of cucumber, which could not be alleviated by MT. These data implied IAA acted as a downstream signal to participate in the MT-induced chilling tolerance of cucumber seedlings. The study has implications for the production of greenhouse cucumber in winter seasons., (© 2024 Scandinavian Plant Physiology Society.)

Glyphosate (GLY), the most widely used herbicide, has been regarded as an emergent environmental contaminant due to its constant and cumulative use, with potential harm to non-target organisms, such as crops, disrupting cells' redox balance. Therefore, plants need to fine-tune their antioxidant (AOX) mechanisms to thrive under GLY-contaminated environments. Proline overaccumulation is a common response in plants exposed to GLY, yet its role in GLY-induced toxicity remains unclear. Thus, this study explores whether Pro overaccumulation in response to GLY is perceived as a downstream tolerance mechanism or an early-warning stress signal. To investigate this, Arabidopsis thaliana T-DNA mutant lines for Pro biosynthetic (P5CS1) and catabolic genes (ProDH) were used and screened for their GLY susceptibility. Upon seedlings' exposure to GLY (0.75 mg L -1 ) for 14 days, the herbicide led to reduced biomass in all genotypes, accompanied by Pro overaccumulation. Mutants with heightened Pro levels (prodh) exhibited the greatest biomass reduction, increased lipid peroxidation (LP), and hydrogen peroxide (H 2 O 2 ) levels, accompanied by a compromised performance of the AOX system. Conversely, p5cs1-4, mutants with lower Pro levels, demonstrated an enhanced AOX system activation, not only with increased levels of glutathione (GSH) and ascorbate (AsA), but also with increased activity of both ascorbate peroxidase (APX) and catalase (CAT). These findings suggest that Pro overaccumulation under GLY exposure is associated with stress sensitivity rather than tolerance, highlighting its potential as an early-warning signal for GLY toxicity in non-target plants and for detecting weed resistance., (© 2024 Scandinavian Plant Physiology Society.)

Pathogenesis-related proteins (PR), including osmotins, play a vital role in plant defense, being activated in response to diverse biotic and abiotic stresses. Despite their significance, the mechanistic insights into the role of osmotins in plant defense have not been extensively explored. The present study explores the cloning and characterization of the osmotin gene (WsOsm) from Withania somnifera, aiming to illuminate its role in plant defense mechanisms. Quantitative real-time PCR analysis revealed significant induction of WsOsm in response to various phytohormones e.g. abscisic acid, salicylic acid, methyl jasmonate, brassinosteroids, and ethrel, as well as biotic and abiotic stresses like heat, cold, salt, and drought. To further elucidate WsOsm's functional role, we overexpressed the gene in Nicotiana tabacum, resulting in heightened resistance against the Alternaria solani pathogen. Additionally, we observed enhancements in shoot length, root length, and root biomass in the transgenic tobacco plants compared to wild plants. Notably, the WsOsm- overexpressing seedlings demonstrated improved salt and drought stress tolerance, particularly at the seedling stage. Confocal histological analysis of H 2 O 2 and biochemical studies of antioxidant enzyme activities revealed higher levels in the WsOsm overexpressing lines, indicating enhanced antioxidant defense. Furthermore, a pull-down assay and mass spectrometry analysis revealed a potential interaction between WsOsm and defensin, a known antifungal PR protein (WsDF). This suggests a novel role of WsOsm in mediating plant defense responses by interacting with other PR proteins. Overall, these findings pave the way for potential future applications of WsOsm in developing stress-tolerant crops and improving plant defense strategies against pathogens., (© 2024 Scandinavian Plant Physiology Society.)

Salinity stress represents a major threat to crop production by inhibiting seed germination, growth of seedlings, and final yield and, therefore, to the social and economic prosperity of developing countries. Recently, plant growth-promoting substances have been widely used as a chemical strategy for improving plant resilience towards abiotic stresses. This study aimed to determine whether melatonin (MT) and glycine betaine (GB) alone or in combination could alleviate the salinity-induced impacts on seed germination and growth of maize seedlings. Increasing NaCl concentration from 100 to 200 mM declined seed germination rate (4.6-37.7%), germination potential (24.5-46.7%), radical length (7.7-40.0%), plumule length (2.2-35.6%), seedling fresh (1.7-41.3%) and dry weight (23.0-56.1%) compared to control (CN) plants. However, MT and GB treatments lessened the adverse effects of 100 and 150 mM NaCl and enhanced germination comparable to control plants. In addition, results from the pot experiments show that 200 mM NaCl stress disrupted the osmotic balance and persuaded oxidative stress, presented by higher electrolyte leakage, hydrogen peroxide, superoxide radicals, and malondialdehyde compared to control plants. However, compared to the NaCl treatment, NaCl+MT+GB treatment decreased the accumulation of malondialdehyde (24.2-42.1%), hydrogen peroxide (36.2-44.0%), and superoxide radicals (20.1-50.9%) by up-regulating the activity of superoxide dismutase (28.4-51.2%), catalase (82.2-111.5%), ascorbate peroxidase (40.3-59.2%), and peroxidase (62.2-117.9%), and by enhancing osmolytes accumulation, thereby reducing NaCl-induced oxidative damages. Based on these findings, the application of MT+GB is an efficient chemical strategy for improving seed germination and growth of seedlings by improving the physiological and biochemical attributes of maize under 200 mM NaCl stress., (© 2024 Scandinavian Plant Physiology Society.)

Reserves of non-structural carbohydrates (NSC) stored in living cells are essential for drought tolerance of trees. However, little is known about the phenotypic plasticity of living storage compartments (SC) and their interactions with NSC reserves under changing water availability. Here, we examined adjustments of SC and NSC reserves in stems and roots of seedlings of two temperate tree species, Acer negundo L. and Betula pendula Roth., cultivated under different substrate water availability. We found that relative contents of soluble NSC, starch and total NSC increased with decreasing water availability in stems of both species, and similar tendencies were also observed in roots of A. negundo. In the roots of B. pendula, soluble NSC contents decreased along with the decreasing water availability, possibly due to phloem decoupling or NSC translocation to shoots. Despite the contrast in organ responses, NSC contents (namely starch) positively correlated with proportions of total organ SC. Individual types of SC showed markedly distinct plasticity upon decreasing water availability, suggesting that water availability changes the partitioning of organ storage capacity. We found an increasing contribution of parenchyma-rich bark to the total organ NSC storage capacity under decreasing water availability. However, xylem SC showed substantially greater plasticity than those in bark. Axial storage cells, namely living fibers in A. negundo, responded more sensitively to decreasing water availability than radial parenchyma. Our results demonstrate that drought-induced changes in carbon balance affect the organ storage capacity provided by living cells, whose proportions are sensitively coordinated along with changing NSC reserves., (© 2024 The Author(s). Physiologia Plantarum published by John Wiley & Sons Ltd on behalf of Scandinavian Plant Physiology Society.)

Premise: Intraspecific variation in drought resistance traits, such as drought escape, appear to be frequent within wild, ruderal forb species. Understanding how these traits are arrayed across the landscape, particularly in association with climate, is critical to developing forbs for wildland restoration programs. Use of forbs is requisite for maintaining biological diversity and ecological services., Methods: Using 6074 greenhouse-grown Chaenactis douglasii seedlings from 95 wild, seed-sourced populations across the western United States, we recorded bolting phenology and estimated genome size using flow cytometry. Mixed-effects regression models were used to assess whether climate of seed origin was predictive for bolting phenology and genome size., Results: Variation in bolting, reflecting an annual vs. perennial lifespan in this species, was observed in 8.7% of the plants, with bolting plants disproportionately occurring in locations with warm, arid climates. Populations with increasing heat and aridity were positively correlated with observed bolting (r = 0.61, p < 0.0001). About one-third (22%) of the total (61%) lifespan variation was attributed to seed source climate and annual heat moisture index, a measure of aridity. Genome size had no significant effect on bolting. Projected climate modeling for mid-century (2041-2070) supports an increasing occurrence of annual lifespan., Conclusions: Our analyses support a drought escape, bet-hedging strategy in C. douglasii. Populations exposed to greater aridity exhibited a higher proportion of individuals with an annual lifespan. Drought escape leading to an annual lifespan can affect how seeds are propagated and deployed for climate-informed restoration., (Published 2024. This article is a U.S. Government work and is in the public domain in the USA.)

Conspecific negative density dependence (CNDD) is thought to be a key process in maintaining plant diversity. However, the strength of CNDD is highly variable in space and time as well as among species, and correlates of this variation that might help to understand and explain it remain largely unquantified. Using Bayesian hierarchical models, we took advantage of 10-year seedling monitoring data that were collected annually in every dry and rainy season in a seasonal tropical forest. We quantified the interspecific variation in the strength of CNDD and its temporal variation. We also examined potential correlates of this interspecific and temporal variation, including species functional traits (such as drought-tolerant traits, defense-related traits, and recourse acquisition traits) and species abundances. In the dry season, we found a negative relationship between the density of neighboring conspecific seedlings on seedling survival, while in the rainy season, there was a negative relationship between the density of neighboring conspecific adults on seedling survival. In addition, we found that interspecific variation in CNDD was related to drought-tolerant traits in the dry season but not in the rainy season. Across years, we found that drought-intolerant species suffer less CNDD during the dry seasons that have higher rainfall, whereas drought-tolerant species suffer less CNDD when the dry season has lower rainfall. We also found that rare species suffered stronger CNDD in the dry season. Overall, our study highlights that CNDD is highly variable among species and through time, necessitating a deeper appreciation of the environmental and functional contexts of CNDD and their interactions., (© 2024 The Ecological Society of America.)

Drought, as a primary environmental factor, imposes significant constraints on developmental processes and productivity of plants. PHDs were identified as stress-responsive genes in a wide range of eukaryotes. However, the regulatory mechanisms governing PHD genes in maize under abiotic stress conditions are still largely unknown and require further investigation. Here, we identified a mutant, zmvil2, in the EMS mutant library with a C to T mutation in the exon of the Zm00001d053875 (VIN3-like protein 2, ZmVIL2), resulting in premature termination of protein coding. ZmVIL2 belongs to PHD protein family. Compared to WT, zmvil2 mutant exhibited increased sensitivity to drought stress. Consistently, overexpression of ZmVIL2 enhances drought resistance in maize. Y2H, BiFC, and Co-IP experiments revealed that ZmVIL2 directly interacts with ZmFIP37 (FKBP12-interacting protein of 37). zmfip37 knockout mutants also exhibit decreased drought tolerance. Interestingly, we demonstrated that ZmABF4 directly binds to the ZmVIL2 promoter to enhance its activity in yeast one hybrid (Y1H), electrophoretic mobility shift assay (EMSA) and dual luciferase reporter assays. Therefore, we uncovered a novel model ZmABF4-ZmVIL2/ZmFIP37 that promotes drought tolerance in maize. Overall, these findings have enriched the knowledge of the functions of PHD genes in maize and provides genetic resources for breeding stress-tolerant maize varieties., (© 2024 John Wiley & Sons Ltd.)

Soil salinization effects plant photosynthesis in a number of global ecosystems. In this study, photosynthetic and physiological parameters were used to elucidate the impacts of saline-alkaline stress on Cyperus esculentus L. (C. esculentus) seedling photosynthesis. The results demonstrate that salt stress, alkali stress and mixed salt and alkali stress treatments all have similar bell-shaped influences on photosynthesis. At low concentrations (0-100 mmol L -1 ), saline-alkaline stress promoted net photosynthetic rate, transpiration rate and water use efficiency in C. esculentus. However, as the treatments increased in intensity (100-200 mmol L -1 ), plant photosynthetic parameters began to decline. We interpreted this as the capacity of C. esculentus to improve osmoregulatory capacity in low saline-alkaline stress treatments by accumulating photosynthetic pigment, proline and malondialdehyde to counterbalance the induced stress - an adaptive mechanism that failed once concentrations reached a critical threshold (100 mmol L -1 ). Stomatal conductance, maximum photosynthetic rate and actual photosynthetic rate all decreased with increasing concentration of the stress treatments, and intercellular carbon dioxide showed a decreasing and then increasing trend. These results indicated that when the saline-alkaline stress concentrations were low, C. esculentus seedlings showed obvious adaptive ability, but when the concentration increased further, the physiological processes of C. esculentus seedlings were significantly affected, with an obvious decrease in photosynthetic efficiency. This study provides a new understanding of the photosynthetic adaptation strategies of C. esculentus seedlings to varying concentrations of saline-alkaline stress., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Male and female dioecious plants often show sexual dimorphism, differing in morphological, physiological and life-history traits. Most previous studies have focused on differences between males and females during or after reproduction, paying little attention to the pre-reproductive stages of the individuals. Here we assessed the response of male and female individuals of the dioecious plant Silene latifolia to abiotic stress at different life stages, including pre-reproductive (i.e. seedlings and young plants) and reproductive individuals. We measured growth, resource allocation and discrimination against 13 C under nutrient deficiency, water stress, as well as their interaction. We observed sexual dimorphism in root growth, with female seedlings having longer main roots than male plants. Pre-reproductive male and female plants also responded differently, in terms of root allocation, to nutrient and water availability. At reproduction, females grew more roots than males when water was not limiting. These differences could help explain the female-skewed sex ratios found in natural populations of S. latifolia. We found no evidence of sexual dimorphism in aboveground dry mass, although females had longer leaves than males at the seedling stage. We conclude that sexual dimorphism in S. latifolia may occur not as a consequence of reproduction, but well before it., (© 2024 The Author(s). Plant Biology published by John Wiley & Sons Ltd on behalf of German Society for Plant Sciences, Royal Botanical Society of the Netherlands.)

Plant-plant interactions are important drivers for the functioning and structuring of dryland plant communities. Stressful conditions, mainly related to water availability, determine whether plant interactions result in net facilitation or competition. Many studies have been conducted on the impacts of mature individuals, trees, shrubs or tussock grasses, on woody seedlings but little is known about the biotic interactions when they all are at the same developmental stage under field conditions. Here we present a spatially replicated study with Olea europaea as the target species and Pistacia lentiscus and Macrochloa tenacissima as neigbors. We also implemented field techniques to increase water availability and, hence, reproduce an abiotic gradient of stress. Wild olive performance was sensitive to neighbors, water availability and site. Improved microcatchments, which in addition to site recreated a gradient of water availability, improved wild olive performance as well as planted neighbors negatively impacted olive seedlings. We observed increasing negative interacting effects as conditions become less stressful. This is in line with the stress-gradient-hypothesis but also provides important knowledge regarding plant interactions in drylands at the same development stage., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The impact of nitrogen (N) and phosphorus (P) on the physiological and biochemical processes crucial for tree seedling growth is substantial. Although the study of plant hydraulic traits in response to N and P is growing, comprehensive research on their combined effects remains limited. Malus sieversii, a key ancestral species of modern apples and a dominant species in Xinjiang's Tianshan wild fruit forest, is witnessing a decline due to climate change, pests and diseases, compounded by challenges in seedling regeneration. Addressing this, a 4-year study was conducted to determine the optimal fertilisation method for it. The experiment explored varying levels of N (N10, N20 and N40) and P (P2, P4 and P8), and their combined effects (N20Px: N20P2, N20P4, N20P8; NxP4: N10P4, N20P4 and N40P4), assessing their impact on gas exchange, hydraulic traits, and the interplay among functional traits in Tianshan Mountains' M. sieversii seedlings. Our study revealed that All N-inclusive fertilisers slightly promoted the net photosynthetic rate. N10 significantly increasing leaf hydraulic conductivity. All P-inclusive fertilisers adversely affected hydraulic conductivity. P8, N20P4 and N20P8 notably increased seedlings' vulnerability to embolism. Seedlings can adaptively adjust multiple functional traits in response to nutrient changes. The research suggests N10 and N20 as the most effective fertilisation treatments for M. sieversii seedlings in this region, while fertilisation involving phosphorus is less suitable. This study contributes valuable insights into the specific nutrient needs of it, vital for conservation and cultivation efforts in the Tianshan region., (© 2024 John Wiley & Sons Ltd.)

High temperature stress is one of the most severe forms of abiotic stress in alfalfa. With the intensification of climate change, the frequency of high temperature stress will further increase in the future, which will bring challenges to the growth and development of alfalfa. Therefore, untargeted metabolomic and RNA-Seq profiling were implemented to unravel the possible alteration in alfalfa seedlings subjected to different temperature stress (25 ℃, 30 ℃, 35 ℃, 40 ℃) in this study. Results revealed that High temperature stress significantly altered some pivotal transcripts and metabolites. The number of differentially expressed genes (DEGs) markedly up and down-regulated was 1876 and 1524 in T30&#95;vs&#95;CK, 2, 815 and 2667 in T35&#95;vs&#95;CK, and 2115 and 2, 226 in T40&#95;vs&#95;CK, respectively. The number for significantly up-regulated and down-regulated differential metabolites was 173 and 73 in T30&#95;vs&#95;CK, 188 and 57 in T35&#95;vs&#95;CK, and 220 and 66 in T40&#95;vs&#95;CK, respectively. It is worth noting that metabolomics and transcriptomics co-analysis characterized enriched in plant hormone signal transduction (ko04705), glyoxylate and dicarboxylate metabolism (ko00630), from which some differentially expressed genes and differential metabolites participated. In particular, the content of hormone changed significantly under T40 stress, suggesting that maintaining normal hormone synthesis and metabolism may be an important way to improve the HTS tolerance of alfalfa. The qRT-PCR further showed that the expression pattern was similar to the expression abundance in the transcriptome. This study provides a practical and in-depth perspective from transcriptomics and metabolomics in investigating the effects conferred by temperature on plant growth and development, which provided the theoretical basis for breeding heat-resistant alfalfa., (© 2024. The Author(s).)

Key Message: Overexpression of rice A20/AN1 zinc-finger protein, OsSAP10, improves water-deficit stress tolerance in Arabidopsis via interaction with multiple proteins. Stress-associated proteins (SAPs) constitute a class of A20/AN1 zinc-finger domain containing proteins and their genes are induced in response to multiple abiotic stresses. The role of certain SAP genes in conferring abiotic stress tolerance is well established, but their mechanism of action is poorly understood. To improve our understanding of SAP gene functions, OsSAP10, a stress-inducible rice gene, was chosen for the functional and molecular characterization. To elucidate its role in water-deficit stress (WDS) response, we aimed to functionally characterize its roles in transgenic Arabidopsis, overexpressing OsSAP10. OsSAP10 transgenics showed improved tolerance to water-deficit stress at seed germination, seedling and mature plant stages. At physiological and biochemical levels, OsSAP10 transgenics exhibited a higher survival rate, increased relative water content, high osmolyte accumulation (proline and soluble sugar), reduced water loss, low ROS production, low MDA content and protected yield loss under WDS relative to wild type (WT). Moreover, transgenics were hypersensitive to ABA treatment with enhanced ABA signaling and stress-responsive genes expression. The protein-protein interaction studies revealed that OsSAP10 interacts with proteins involved in proteasomal pathway, such as OsRAD23, polyubiquitin and with negative and positive regulators of stress signaling, i.e., OsMBP1.2, OsDRIP2, OsSCP and OsAMTR1. The A20 domain was found to be crucial for most interactions but insufficient for all interactions tested. Overall, our investigations suggest that OsSAP10 is an important candidate for improving water-deficit stress tolerance in plants, and positively regulates ABA and WDS signaling via protein-protein interactions and modulation of endogenous genes expression in ABA-dependent manner., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Plants can acclimate their photosynthesis to growth temperature, but the contribution of local adaptation to intraspecific variation in thermal acclimation of photosynthesis is not fully understood. Here, we experimentally investigated the photosynthetic thermal acclimation in Fagus crenata Blume seedlings from two populations growing at different elevations and temperature regimes (low- and high-elevation sites) in northern Japan. We acclimated seedlings for 14 to 23 days at daytime temperatures of either 22 °C (control) or 27 °C (warm treatment) and obtained photosynthetic temperature-response curves in the range of 19 to 32 °C. The optimum temperature of photosynthesis (Topt) was ~0.6 °C higher in seedlings acclimated at 27 °C than in those acclimated at 22 °C, and it was significantly lower in seedlings with higher stomatal sensitivity to leaf-to-air vapor pressure deficit than in those with lower sensitivity. The effects of warm treatment, population and treatment-population interaction on Topt were not significant in the two-way analysis of variance, but the effect of treatment became significant when stomatal sensitivity to leaf-to-air vapor pressure deficit was included as a covariate in the model. Structural equation modeling indicated that seedlings with lower root biomass had lower Topt because of the high stomatal sensitivity to leaf-to-air vapor pressure deficit. Structural equation modelling also indicated that the way of shifting the Topt differed between the two populations: seedlings from a high-elevation site depended on decreasing photosynthetic rates at low temperatures for the increase in Topt but seedlings from a low-elevation site did not. We suggest that the difference in thermal acclimation of photosynthesis between the two populations may reflect adaptation to different climate regimes and that belowground traits should be considered when investigating thermal acclimation capacity, especially in seedlings., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)