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The kiwifruit canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) seriously threatens the development of kiwifruit industry. So far, only a limited number of Psa-resistant kiwifruit varieties have been identified, and the underlying molecular mechanisms are still largely unknown. In this study, we evaluated the Psa resistance of six hybrid populations and screened a resistant segregation population R1F2. Then, transcriptome analysis on the Psa extremely high-resistant (HR) and extremely high-susceptible (HS) plants of the R1F2 population was performed. KEGG enrichment analysis revealed that differentially expressed genes (DEGs) were significantly enriched in plant hormone signal transduction pathways, including auxin, abscisic acid, zeatin, jasmonic acid and salicylic acid. Furthermore, several transcription factors (TFs), especially WRKY TFs, were identified among the DEGs. The qRT-PCR showed that AcWRKY75 was highly expressed in the HS plants. Additionally, AcWRKY75 was significantly induced in the HS cultivar 'Hongyang' after Psa inoculation. Sequence amplification analysis showed that there was polymorphism in the DNA sequence of AcWRKY75 gene, but no HR or HS-specific differences were observed. Subcellular localization and transcriptional activity analysis confirmed that AcWRKY75 functions as a nucleus-located transcriptional activator. Transient overexpression of AcWRKY75 in kiwifruit leaves reduced the resistance to Psa, while silencing AcWRKY75 by virus-induced gene silencing (VIGS) slightly enhanced the resistance to Psa. Furthermore, AcWRKY75 exhibited a weak interaction with the promoter of the ABA-related DEG AcBet V1 (Acc27163). Our findings elucidated that AcWRKY75 may negatively regulate the Psa resistance of kiwifruit through the hormone signaling pathway, which laid a foundation for the analysis of the disease resistance mechanism of kiwifruit canker. [ABSTRACT FROM AUTHOR]

Background: Trihliex transcription factors (TFs) play crucial roles in plant growth and development, stress response, and plant hormone signaling network transmission. In order to comprehensively investigate the functions of trihliex genes in eggplant development and the abiotic stress response, we conducted an extensive analysis of the trihliex gene family in the eggplant genome. Results: In this study, 30 trihelix gene family members were unevenly distributed on 12 chromosomes. On the basis of their phylogenetic relationships, these genes were conserved in different plant species and could be divided into six subfamilies, with trihelix genes within the same subfamily sharing similar structures. The promoter regions of trihelix genes contained cis-acting elements related to plant growth and development, plant hormones, and abiotic stress responses, suggesting potential applications in the development of more resistant crops. Selective pressure assessments indicated that trihliex genes have undergone purifying selection pressure. Expression analysis on the basis of transcriptomic profiles revealed that SmGT18, SmGT29, SmGT6, and SmGT28 are highly expressed in roots, leaves, flowers, and fruits, respectively. Expression analysis via quantitative real-time PCR (qRT‒PCR) revealed that most trihelix genes respond to low temperature, abscisic acid (ABA), and salicylic acid (SA), with SmGT29 exhibiting significant upregulation under cold stress conditions. The SmGT29 gene was subsequently successfully cloned from eggplant, which was located in the nucleus, robust transcriptional activity, and a protein molecular weight of 74.59 kDa. On the basis of these findings, SmGT29 was postulated to be a pivotal candidate gene that actively responds to biotic stress stimuli, thereby supporting the plant's innate stress resistance mechanisms. Conclusion: In summary, this study was the first report on trihelix genes and their potential roles in eggplant plants. These results provided valuable insights for enhancing stress resistance and quality traits in eggplant breeding, thereby serving as a crucial reference for future improvement efforts. [ABSTRACT FROM AUTHOR]

Background: Pumpkin (Cucurbita moschata) is an important vegetable crop that often suffers from low-temperature stress during growth. However, the molecular mechanism involved in its response to chilling stress remains unknown. In this study, we comprehensively investigated the effect of chilling stress in pumpkin seedlings by conducting physiological, transcriptomic, and metabolomic analyses. Results: Under chilling stress, there was an overall increase in relative electrical conductivity, along with malondialdehyde, soluble sugar, and soluble protein contents, but decreased superoxide dismutase and peroxidase activities and chlorophyll contents in seedling leaves compared with controls. Overall, 5,780 differentially expressed genes (DEGs) and 178 differentially expressed metabolites (DEMs) were identified under chilling stress. Most DEGs were involved in plant hormone signal transduction and the phenylpropanoid biosynthesis pathway, and ERF, bHLH, WRKY, MYB, and HSF transcription factors were induced. Metabolomic analysis revealed that the contents of salicylic acid (SA), phenylalanine, and tyrosine increased in response to chilling stress. The findings indicated that the SA signaling and phenylpropanoid biosynthesis pathways are key to regulating the responses to chilling stress in pumpkins. Conclusion: Overall, our study provides valuable insights into the comprehensive response of C. moschata to chilling stress, enriching the theoretical basis of this mechanism and facilitating the development of molecular breeding strategies for pumpkin tolerance to chilling stress. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA) is a key plant hormone that regulates plant growth and response to stress. Pyrabactin resistance 1-like (PYR/PYL) proteins are ABA receptors involved in the initial steps of ABA signaling. Triticum monococcum L. subsp. aegilopoides is an important germplasm resource for wheat. In this study, we identified 15 PYL genes from T. monococcum L. subsp. aegilopoides and found that they were distributed across five chromosomes. Based on phylogenetic analysis, we classified these genes into three subfamilies. Members of each subfamily have similar gene structures and contain a common motif. Further analysis revealed that the promoters have multiple hormone-related elements. We found 7, 33, and 49 collinear gene pairs in three different ploidy wheat species (T. urartu, T. turgidum and T. aestivum), indicating that PYL genes are relatively conserved during the process of wheat polyploidization. Additionally, interaction networks and miRNA targets were predicted, revealing interactions between PYL proteins and key components of the abscisic acid signaling network. miR9666b-3p may serve as a central factor in PYL involvement in the abscisic acid network. Through RNA-seq analysis and qPCR validation, three genes (TbPYL2, TbPYL5, and TbPYL12) were found to potentially play a role in cold stress. These findings lay the groundwork for further research on PYL genes in T. monococcum L. subsp. aegilopoides. [ABSTRACT FROM AUTHOR]

Salicornia europaea, commonly known as glasswort, thrives in reclaimed land and coastal areas with high salinity, demonstrating remarkable adaptation to the arid conditions of such environments. Two aerobic, Gram-stain-negative, non-motile, rod-shaped bacterial strains, designated TR-M5T and TR-M9, were isolated from the root of Salicornia europaea plants. These bacteria exhibit plant growth-promoting and salt tolerance-enhancing abilities, which have not been reported in other species of the genus. Both strains produce indole-3-acetic acid (IAA), a plant growth hormone, and synthesize proline, which functions as an osmoprotectant. Additionally, they possess gelatinase and cellulase activities. Cells grow in temperatures from 4 to 42°C (optimum 25°C), pH levels from 6.0 to 9.0 (optimum 7.0), and NaCl concentrations from 0 to 8.0% (optimum 6.0%). The average nucleotide identity and digital DNA-DNA hybridization values of strain TR-M5T with the most closely related type strains for which whole genomes are publicly available were 74.05-77.78% and 18.6-23.1%, respectively. Phylogenetic analysis of their 16S rRNA gene sequences revealed that strains TR-M5T and TRM9 belong to the genus Algoriphagus. A. locisalis exhibited the highest similarity, sharing a sequence identity of 98.1%. The genomes of TR-M5T and TR-M9 exhibit a G + C content of 43 mol%. This study specifically focuses on the identification and characterization of strain TR-M5T as a novel species within the genus Algoriphagus, which we propose to name Algoriphagus halophytocola sp. nov., highlighting its potential role in enhancing plant growth and salt tolerance in saline environments. The type strain is TR-M5T (KCTC 92720T = GDMCC 1.3797T). [ABSTRACT FROM AUTHOR]

Peptide hormones regulate plant development, growth, and stress responses. Sulfated peptides represent a class of proteins that undergo posttranslational modification by tyrosylprotein sulfotransferase (TPST), followed by specific enzymatic cleavage to generate mature peptides. This process contributes to the formation of various bioactive peptides, including PSKs (PHYTOSULFOKINEs), PSYs (PLANT PEPTIDE CONTAINING SULFATED TYROSINE), CIFs (CASPARIAN STRIP INTEGRITY FACTOR), and RGFs (ROOT MERISTEM GROWTH FACTOR). In the past three decades, significant progress has been made in understanding the molecular mechanisms of sulfated peptides that regulate plant development, growth, and stress responses. In this review, we explore the sequence properties of precursors, posttranslational modifications, peptide receptors, and signal transduction pathways of the sulfated peptides, analyzing their functions in plants. The cross-talk between PSK/RGF peptides and other phytohormones, such as brassinosteroids, auxin, salicylic acid, abscisic acid, gibberellins, ethylene, and jasmonic acid, is also described. The significance of sulfated peptides in crops and their potential application for enhancing crop productivity are discussed, along with future research directions in the study of sulfated peptides. [ABSTRACT FROM AUTHOR]

Graft healing involves a series of cytological and molecular events including wound responses, callus formation and vascular bundle remodelling. Hormones are important signalling molecules regulating plant development and responses to environmental stimuli. However, the detailed dynamics of phytohormones in graft healing remain elusive. In this research, internodes above and below the graft site were harvested from 0 to 168 h after grafting (HAG), and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to determinate jasmonic acid, auxin, cytokinin, ethylene, salicylic acid, abscisic acid and gibberellin levels during the graft healing process. Uniform manifold approximation and projection (UMAP) and k-means analyses were performed to explore hormone spatio-temporal dynamics. We found the stage-specific and asymmetric accumulation of phytohormones in the tomato graft healing process. At the early healing stage (before vascular bundle reconnection), IAA, cZ, ABA, JA and SA mainly accumulated above the graft site, while tZ and ACC mainly accumulated below the graft site. MEIAA, ICAld and IP mainly accumulated at the later stage. Comminated with the healing process, we suggested that JA is mainly involved in wound responses, IAA is beneficial to the formation of callus and vascular cell development, tZ promotes cell division, and IP is linked to vascular bundle remodelling. In addition, expression of JA-related genes SlMYC2 and SlJAZ2, IAA-related gene SlIAA1, tZ-related genes SlHP2 and SlRR8, and IP-related gene SlRR9 correlated with hormone accumulation. The findings provide important information about the hormones and genes involved in the tomato graft healing process. [ABSTRACT FROM AUTHOR]

Strigolactones are phytohormones that influence arbuscular mycorrhizal fungal (AMF) spore germination, pre-symbiotic hyphal branching, and metabolic rates. Historically, strigolactone effects have been tested on single AMF strains. An open question is whether intraspecific variation in strigolactone effects and intraspecific interactions can influence AMF competition. Using the Rhizophagus irregularis strains A5 and C2, we tested for intraspecific variation in the response of germination and pre-symbiotic growth (i.e., hyphal length and branching) to the strigolactones GR24 and 5-deoxystrigol. We also tested if interactions between these strains modified their germination rates and pre-symbiotic growth. Spore germination rates were consistently high (> 90%) for C2 spores, regardless of treatment and the presence of the other strain. For A5 spores, germination was increased by strigolactone presence from approximately 30 to 70% but reduced when grown in mixed culture. When growing together, branching increased for both strains compared to monocultures. In mixed cultures, strigolactones increased the branching for both strains but led to an increase in hyphal length only for the strain A5. These strain-specific responses suggest that strigolactones may have the potential to shift competitive dynamics among AMF species with direct implications for the establishment of the AMF community. [ABSTRACT FROM AUTHOR]

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

Phytochrome-interacting factors (PIFs) are a subgroup of transcription factors within the basic helix-loop-helix (bHLH) family, playing a crucial role in integrating various environmental signals to regulate plant growth and development. Despite the significance of PIFs in these processes, a comprehensive genome-wide analysis of PIFs in conifers has yet to be conducted. In this investigation, three PtPIF genes were identified in Chinese pine, categorized into three subgroups, with conserved motifs indicating the presence of the APA/APB motif and bHLH domain in the PtPIF1 and PtPIF3 proteins. Phylogenetic analysis revealed that the PtPIF1 and PtPIF3 proteins belong to the PIF7/8 and PIF3 groups, respectively, and were relatively conserved among gymnosperms. Additionally, a class of PIF lacking APA/APB motif was identified in conifers, suggesting its function may differ from that of traditional PIFs. The cis-elements of the PtPIF genes were systematically examined, and analysis of PtPIF gene expression across various tissues and under different light, temperature, and plant hormone conditions demonstrated similar expression profiles for PtPIF1 and PtPIF3. Investigations into protein-protein interactions and co-expression networks speculated the involvement of PtPIFs and PtPHYA/Bs in circadian rhythms and hormone signal transduction. Further analysis of transcriptome data and experimental validation indicated an interaction between PtPIF3 and PtPHYB1, potentially linked to diurnal rhythms. Notably, the study revealed that PtPIF3 may be involved in gibberellic acid (GA) signaling through its interaction with PtDELLAs, suggesting a potential role for PtPIF3 in mediating both light and GA responses. Overall, this research provides a foundation for future studies investigating the functions of PIFs in conifer growth and development. [ABSTRACT FROM AUTHOR]

In plants, vegetative growth is controlled by synergistic and/or antagonistic effects of many regulatory factors. Here, the authors demonstrate that the ubiquitin ligase seven in absentia1 (SINA1) mammalian BTF2‐like transcription factors, Drosophila synapse‐associated proteins, and yeast DOS2‐like proteins (BSD1) function as a regulatory module to control vegetative growth in tomato via regulation of the production of plant growth hormone gibberellin (GA). SINA1 negatively regulates the protein level of BSD1 through ubiquitin‐proteasome‐mediated degradation, and the transgenic tomato over‐expressing SINA1 (SINA1‐OX) resembles the dwarfism phenotype of the BSD1‐knockout (BSD1‐KO) tomato plant. BSD1 directly activates expression of the BSD1‐regulated gene 1 (BRG1) via binding to a novel core BBS (standing for BSD1 binding site) binding motif in the BRG1 promoter. Knockout of BRG1 (BRG1‐KO) in tomato also results in a dwarfism phenotype, suggesting BRG1 plays a positive role in vegetative growth as BSD1 does. Significantly, GA contents are attenuated in transgenic SINA1‐OX, BSD1‐KO, and BRG1‐KO plants exhibiting dwarfism phenotype and exogenous application of bioactive GA3 restores their vegetative growth. Moreover, BRG1 is required for the expression of multiple GA biosynthesis genes and BSD1 activates three GA biosynthesis genes promoting GA production. Thus, this study suggests that the SINA1‐BSD1 module controls vegetative growth via direct and indirect regulation of GA biosynthesis in tomato. [ABSTRACT FROM AUTHOR]

Background: Two-line hybrid wheat technology system is one way to harness wheat heterosis both domestically and internationally. Seed vigor is a crucial parameter for assessing seed quality, as enhanced seed vigor can lead to yield increments of over 20% to a certain extent. MicroRNAs (miRNAs) were known to participate in the development and vigor of seed in plants, but its impact on seed vigor in two-line hybrid wheat remains poorly elucidated. Results: The hybrid (BS1453/11GF5135) wheat exhibited superiority in seed vigor and anti-aging capacity, compared to its male parent (11GF5135, MP) and female parent (BS1453, FP). We identified four miRNAs associated with seed vigor, all of which are novel miRNAs. The majority of targets of miRNAs were related to ubiquitin ligases, kinases, sucrose synthases and hydrolases, involving in starch and sucrose metabolism, hydrolysis, catalysis, plant hormone signal transduction, and other pathways, which played crucial roles in seed development. Additionally, we also found miR531 was differentially expressed in both male parent and hybrid, and its target gene was a component of the E1 subunit of α-ketoate dehydrogenase complex, which interacted with dihydrolipoamide acetyltransferase (E2) and dihydrolipoyl dehydrogenase (E3). Finally, We established a presumptive interaction model to speculate the relationship of miR531 and seed vigor. Conclusions: This study analyzed the seed vigor of two-line hybrid wheat, and screened seed vigor-related miRNAs. Meanwhile speculated the genetic relationship of hybrid and parents, in terms of miRNAs. Consequently, the present study provides new insights into the miRNA-mediated gene and protein interaction network that regulates seed vigor. These findings hold significance for enhancing the yield and quality of two-line hybrid wheat, facilitating its future applications. [ABSTRACT FROM AUTHOR]

Introduction: Phytohormones play a crucial role in regulating the abscission of plant organs and tissues. Methods: In this study, the ultrastructure of the sepals of Korla fragrant pears was observed using a transmission electron microscope, and high-performance liquid and gas chromatography were used to analyze the dynamic changes of phytohormones in the abscission zone during the calyx abscission process of Korla fragrant pears, and mass spectrometry imaging was applied to ascertain the spatial distribution of phytohormones. Results: The results revealed that the mitochondria in the abscission zone of the decalyx fruits were regularly distributed around the cell wall, and the chloroplasts were moderately present. In contrast, in the persistent calyx fruit, the corresponding parts of the abscission zone showed a scattered distribution of mitochondria within the cells, and there was a higher number of chloroplasts, which also contained starch granules inside. Mass spectrometry imaging revealed that ABA was enriched in the abscission zone of the decalyx fruit, and their ionic signal intensities were significantly stronger than those of the persistent calyx fruit. However, the ionic signal intensities of Indole-3-acetic acid (IAA) and Gibberellin A3 (GA3) of the persistent calyx fruit were significantly stronger than those in the abscission zone of the decalyx fruit and were concentrated in the persistent calyx fruit. 1-Aminocyclopropanecarboxylic Acid (ACC) did not show distinct regional distribution in both the decalyx and persistent calyx fruits. Furthermore, before the formation of the abscission zone, the levels of IAA, GA3, and zeatin (ZT) in the abscission zone of the decalyx fruits were significantly lower than those in the persistent calyx fruits by 37.9%, 57.7%, and 33.0%, respectively, while the levels of abscisic acid (ABA) and ethylene (ETH) were significantly higher by 21.9% and 25.0%, respectively. During the formation of the abscission zone, the levels of IAA, GA3, and ZT in the abscission zone of the decalyx fruits were significantly lower than those in the persistent calyx fruits by 41.7%, 71.7%, and 24.6%, respectively, while the levels of ABA and ETH were significantly higher by 15.2% and 80.0%, respectively. After the formation of the abscission zone, the levels of IAA and GA3 in the abscission zone of the decalyx fruits were lower than those in the persistent calyx fruits by 20.8% and 47.8%, respectively, while the levels of ABA and ETH were higher by 271.8% and 26.9%, respectively. In summary, during the calyx abscission process of Korla fragrant pears, IAA and GA3 in the abscission zone inhibited abscission, while ABA and ETH promoted calyx abscission. These research findings enrich the understanding of the regulatorymechanism of plant hormones on calyx abscission and provide a theoretical basis for the study of exogenous plant growth regulators for regulating calyx abscission in Korla fragrant pear. [ABSTRACT FROM AUTHOR]

Plant somatic embryogenesis (SE) is an efficient regeneration system for propagation. It involves the regulation of a complex molecular regulatory network encompassing endogenous hormone synthesis, metabolism, and signal transduction processes, induced through exogenous plant growth regulators. Previous studies have focused primarily on traditional propagation methods for Tectona grandis, but there is limited knowledge on SE and its hormonal regulatory mechanisms. In our study, different SE stages, including the nonembryogenic callus (NEC), embryogenic callus (EC), and globular and heartshaped embryo (E-SEs) stages, were induced in teak cotyledons incubated on MS medium supplemented with 0.1 mg/L thidiazuron (TDZ). Morphological and histological observations indicated that EC primarily originates from the development of embryogenic cell clusters. During SE induction, the levels of six classes of endogenous hormones, IAA, CTK, ETH, ABA, SA, and JA, changed significantly. Transcriptome analysis revealed that endogenous hormones participate in SE induction in teak through various biological processes, such as biosynthesis, metabolism, and signal transduction pathways. We found that IAA biosynthesis primarily occurs through the IAM pathway during these three stages. The ETH receptor kinase gene SERF1 exhibited the highest expression levels in E-SEs. The ABA-, SA-, and JA-related signal transduction genes ABI3, NPR1, and JAZ exhibited no differential expression during different stages. Moreover, key encoding genes of SE regulators, including WUS, WOX and SERK, were differentially expressed during SE. In conclusion, this study offers insights into the roles of endogenous hormones and their interactions during SE induction. [ABSTRACT FROM AUTHOR]

Background: Castor is an important industrial raw material. Drought-induced oxidative stress leads to slow growth and decreased yields in castor. However, the mechanisms of drought-induced oxidative stress in castor remain unclear. Therefore, in this study, physiological, biochemical, and RNA-seq analyses were conducted on the roots of castor plants under PEG-6000 stress for 3 d and 7 d followed by 4 d of hydration. Results: The photosynthetic rate of castor leaves was inhibited under PEG-6000 stress for 3 and 7 d. Biochemical analysis of castor roots stressed for 3 d and 7 d, and rehydrated for 4 d revealed that the activities of APX and CAT were highest after only 3 d of stress, whereas the activities of POD, GR, and SOD peaked after 7 d of stress. RNA-seq analysis revealed 2926, 1507, and 111 differentially expressed genes (DEGs) in the roots of castor plants under PEG-6000 stress for 3 d and 7 d and after 4 d of rehydration, respectively. GO analysis of the DEGs indicated significant enrichment in antioxidant activity. Furthermore, KEGG enrichment analysis of the DEGs revealed significantly enriched metabolic pathways, including glutathione metabolism, fatty acid metabolism, and plant hormone signal transduction. WGCNA identified the core genes PP2C39 and GA2ox4 in the navajowhite1 module, which was upregulated under PEG-6000 stress. On the basis of these results, we propose a model for the response to drought-induced oxidative stress in castor. Conclusions: This study provides valuable antioxidant gene resources, deepening our understanding of antioxidant regulation and paving the way for further molecular breeding of castor plants. [ABSTRACT FROM AUTHOR]

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

Broomcorn millet (Panicum miliaceum L.) is one of the earliest crops, domesticated nearly 8000 years ago in northern China. It gradually spread across the entire Eurasian continent, as well as to America and Africa, with recent improvement in various reproductive and vegetative traits. To identify the genes that were selected during the domestication and improvement processes, we performed a comparative transcriptome analysis based on wild types, landraces, and improved cultivars of broomcorn millet at both seeding and filling stages. The variations in gene expression patterns between wild types and landraces and between landraces and improved cultivars were further evaluated to explore the molecular mechanisms underlying the domestication and improvement of broomcorn millet. A total of 2155 and 3033 candidate genes involved in domestication and a total of 84 and 180 candidate genes related to improvement were identified at seedling and filling stages of broomcorn millet, respectively. The annotation results suggested that the genes related to metabolites, stress resistance, and plant hormones were widely selected during both domestication and improvement processes, while some genes were exclusively selected in either domestication or improvement stages, with higher selection pressure detected in the domestication process. Furthermore, some domestication- and improvement-related genes involved in stress resistance either lost their functions or reduced their expression levels due to the trade-offs between stress resistance and productivity. This study provided novel genetic materials for further molecular breeding of broomcorn millet varieties with improved agronomic traits. [ABSTRACT FROM AUTHOR]

Background: The NAC transcription factor family, which is recognized as one of the largest plant-specific transcription factor families, comprises numerous members that are widely distributed among various higher plant species and play crucial regulatory roles in plant immunity. Results: In this paper, we provided a detailed summary of the roles that NAC transcription factors play in plant immunity via plant hormone pathways and reactive oxygen species pathways. In addition, we conducted in-depth investigations into the interactions between NAC transcription factors and pathogen effectors to summarize the mechanism through which they regulate the expression of defense-related genes and ultimately affect plant disease resistance. Conclusions: This paper presented a comprehensive overview of the crucial roles that NAC transcription factors play in regulating plant disease resistance through their involvement in diverse signaling pathways, acting as either positive or negative regulators, and thus provided references for further research on NAC transcription factors. [ABSTRACT FROM AUTHOR]

Auxin is the first plant hormone found to play a dominant role in fruit growth, from fruit set to fruit ripening. Strawberry plants represent a suitable model for studying auxin's biosynthesis, sensing, and signaling machinery. Aux/IAA genes are a classical rapid auxin-responsive family. However, the Aux/IAA gene family in Fragaria genus is poorly understood. In this study, a total of 287 Aux/IAA genes were identified in the eight strawberry genomes. Their physicochemical properties, domain structure, and cis-regulatory elements revealed the functional multiplicity of the strawberry Aux/IAAs. We used a phylogenetic analysis to classify these genes into 12 classes. In addition, based on synteny analysis, gene duplications, and calculation of the Ka/Ks ratio, we found that segmental duplications promote the evolution of Aux/IAAs in Fragaria species, which is followed by purifying selection. Furthermore, the expression pattern and protein–protein interaction network of these genes in Fragaria vesca revealed various tissue-specific expressions and probable regulatory functions. Taken together, these results provide basic genomic information and a functional analysis of these genes, which will serve to expand our understanding of the direction in which the Aux/IAA gene family is evolving in Fragaria species. [ABSTRACT FROM AUTHOR]

Bud-notching in pear varieties with weak-branches enhances branch development, hormone distribution, and germination, promoting healthier growth and improving early yield. To examine the regulatory mechanisms of endogenous hormones on lateral bud germination in Pyrus spp. (cv. 'Huangguan') (Pyrus bretschneideri Rehd.), juvenile buds were collected from 2-year-old pear trees. Then, a comprehensive study, including assessments of endogenous hormones, germination and branching rates, RNA-seq analysis, and gene function analysis in these lateral buds was conducted. The results showed that there was no significant difference in germination rate between the control and bud-notching pear trees, but the long branch rate was significantly increased in bud-notching pear trees compared to the control (p < 0.05). After bud-notching, there was a remarkable increase in IAA and BR levels in the pruned section of shoots, specifically by 141% and 93%, respectively. However, the content of ABA in the lateral buds after bud-notching was not significantly different from the control. Based on RNA-seq analysis, a notable proportion of the differentially expressed genes (DEGs) were linked to the plant hormone signal transduction pathway. Notably, the brassinosteroid signaling pathway seemed to have the closest connection with the branching ability of pear with the related genes encoding BRI1 and CYCD3, which showed significant differences between lateral buds. Finally, the heterologous expression of PyCYCD3 has a positive regulatory effect on the increased Arabidopsis growth and branching numbers. Therefore, the PyCYCD3 was identified as an up-regulated gene that is induced via brassinosteroid (BR) and could act as a conduit, transforming bud-notching cues into proliferative signals, thereby governing lateral branching mechanisms in pear trees. [ABSTRACT FROM AUTHOR]

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

Huangjing is becoming a new generation of crop. Polygonatum kingianum var. grandifolium (XHJ) is a variant of P. kingianum (DHJ), and they are treated as Huangjing. Unlike other Polygonatum species, the rhizome bud of XHJ can germinate both in spring and autumn, which contributes to its high rhizome yield. However, the molecular mechanism of the autumn shooting of XHJ was still unknown. In the present study, cellular observation, comparative targeted metabolome of phytohormones, and transcriptome analysis between XHJ and DHJ in autumn were conducted. Interestingly, 'Diterpenoid biosynthesis' (ko00904) and 'Plant hormone signal transduction' (ko04075) were commonly enriched by differentially accumulated phytohormones (DAPs) and differentially expressed genes (DEGs) in all tissues, which indicated the high auxin content, low cytokinin (CTK) content, and low abscisic acid/gibberellin (ABA/GA) ratio might contribute to the XHJ rhizome buds' differentiation and germination in autumn. Moreover, according to the weighted gene co-expression network analysis (WCGNA), transcript factors (TFs) related to auxin, CTK, GA, and jasmonic acid (JA) metabolism were screened, such as AP2/ERFs, WRKY, and NAC, which deserve further research. In conclusion, we comprehensively illustrated the mechanism of XHJ natural autumn shooting through cytological, metabolic, and transcriptomic analysis, which improves our understanding of the high yield of XHJ rhizomes and the diversity of shooting mechanisms in Polygonatum to lay the foundation for the further development of the Huangjing industry. [ABSTRACT FROM AUTHOR]

Botryosphaeria dothidea is the main fungal pathogen responsible for causing Chinese hickory (Carya cathayensis) dry rot disease, posing a serious threat to the Chinese hickory industry. Understanding the molecular basis of B. dothidea infection and the host’s resistance mechanisms is crucial for controlling and managing the ecological impact of Chinese hickory dry rot disease. This study utilized ultrastructural observations to reveal the process of B. dothidea infection and colonization in Chinese hickory, and investigated the impact of B. dothidea infection on Chinese hickory biochemical indicators and plant hormone levels. Through high-throughput transcriptome sequencing, the gene expression profiles associated with different stages of B. dothidea infection in Chinese hickory and their corresponding defense responses were described. Additionally, a series of key genes closely related to non-structural carbohydrate metabolism, hormone metabolism, and plant-pathogen interactions during B. dothidea infection in Chinese hickory were identified, including genes encoding DUF, Myb_DNA-binding, and ABC transporter proteins. These findings provide important insights into elucidating the pathogenic mechanisms of B. dothidea and the resistance genes in Chinese hickory. [ABSTRACT FROM AUTHOR]

ATP‐binding cassette (ABC) transporters hydrolyse ATP to transport various substrates. Previous studies have shown that ABC transporters are responsible for transporting plant hormones and heavy metals, thus contributing to plant immunity. Herein, we identified a wheat G‐type ABC transporter, TaABCG2‐5B, that responds to salicylic acid (SA) treatment and is induced by Fusarium graminearum, the primary pathogen causing Fusarium head blight (FHB). The loss‐of‐function mutation of TaABCG2‐5B (ΔTaabcg2‐5B) reduced SA accumulation and increased susceptibility to F. graminearum. Conversely, overexpression of TaABCG2‐5B (OE‐TaABCG2‐5B) exerted the opposite effect. Quantification of intracellular SA in ΔTaabcg2‐5B and OE‐TaABCG2‐5B protoplasts revealed that TaABCG2‐5B acts as an importer, facilitating the transport of SA into the cytoplasm. This role was further confirmed by Cd2+ absorption experiments in wheat roots, indicating that TaABCG2‐5B also participates in Cd2+ transport. Thus, TaABCG2‐5B acts as an importer and is crucial for transporting multiple substrates. Notably, the homologous gene TaABCG2‐5A also facilitated Cd2+ uptake in wheat roots but did not significantly influence SA accumulation or FHB resistance. Therefore, TaABCG2 could be a valuable target for enhancing wheat tolerance to Cd2+ and improving FHB resistance. [ABSTRACT FROM AUTHOR]

The study of the reproduction characteristics of roses of the garden class Shrub, the definition of the dependence of the hormonal determination of explant rhizogenesis on the concentrations of phytohormones that are part of the nutrient medium, are relevant and has both scientific and practical interest. This study presents the results of studies of hormonal determination of rhizogenesis in explants of cultivars of roses of the garden class Shrub: Gärtnerfreude, Lavender Dream, Pomponella, Red Cascade, Sommerabend cultivated in vitro on nutrient medium containing growth regulators. It has been established that of the nutrient medium modified by the addition of 0.2-1.0 mg/l α-naphthylacetic acid (α-NAA), the most effective was the medium with the content of α-NAA 0.5 mg/l, the content of macro- and microelements half of the Murashige and Skoog prescriptions, and a decrease in the sucrose content to 2.0%. On this medium, the frequency of rhizogenesis averaged 61.2% for the studied cultivars. Hormonal determination of rhizogenesis and efficiency of root formation in vitro in the Shrub rose regenerants depended on the genotype of the plant: cv. Lavender Dream (66.0%) and cv. Sommerabend (67.0%) had the highest rhizogenesis ability. The use of the universal growth regulator Humifield in combination with 0.5 mg/l α-NAA contributed to an increase in the rooting rate of the studied rose cultivars up to 70.0-86.0%. [ABSTRACT FROM AUTHOR]

Actinidia arguta is a cold-resistant fruit tree but intolerant to waterlogging. Waterlogging stress is the major abiotic stress in A. arguta growth, and several pathways are involved in the response mechanisms. Fifteen physiological indices and transcriptome data of two A. arguta cultivars, which showed two forms under waterlogging, were used to identify the major factor following the leaf senescence in waterlogging. Through principal component analysis (PCA) of 15 physiological indices in 'Kuilv' and 'Lvwang', the hormone contents were selected as the most important principal component (PCA 2) out of four components in response to waterlogging stress. According to the analysis of transcriptome data, 21,750 differentially expressed genes were identified and 10 genes through WGCNA, including hormone metabolism and sucrose metabolism, were screened out on the 6th day of waterlogging. In particular, the ABA signal transduction pathway was found to be closely related to the response to waterlogging based on the correlation analysis between gene expression level and plant hormone content, which may have regulated physiological indicators and morphological changes together with other hormones. Overall, the phenomenon of leaves falling induced by ABA might be a protective mechanism. The results provided more insights into the response mechanism of coping with waterlogging stress in A. arguta. [ABSTRACT FROM AUTHOR]

Background The growth habit (GH), also named the branching habit, is an important agronomic trait of peanut and mainly determined by the lateral branch angle (LBA). The branching habit is closely related to peanut mechanized farming, pegging, yield, and disease management. Objectives However, the molecular basis underlying peanut LBA needs to be uncovered. Methods In the present study, an erect branching peanut mutant, eg06g, was obtained via 60Co γ-ray-radiating mutagenesis of a spreading-type peanut cultivar, Georgia-06G (G06G). RNA-seq was performed to compare the transcriptome variation of the upper sides and lower sides of the lateral branch of eg06g and G06G. Results In total, 4908 differentially expressed genes (DEGs) and 5833 DEGs were identified between eg06g and G06G from the lower sides and upper sides of the lateral branch, respectively. GO, KEGG, and clustering enrichment analysis indicated that the carbohydrate metabolic process, cell wall organization or biogenesis, and plant hormone signal transduction were mainly enriched in eg06g. Conclusions Further analysis showed that the genes involved in starch biosynthesis were upregulated in eg06g, which contributed to amyloplast sedimentation and gravity perception. Auxin homeostasis and transport-related genes were found to be upregulated in eg06g, which altered the redistribution of auxin in eg06g and in turn triggered apoplastic acidification and activated cell wall modification-related enzymes, leading to tiller angle establishment through the promotion of cell elongation at the lower side of the lateral branch. In addition, cytokinin and GA also demonstrated synergistic action to finely regulate the formation of peanut lateral branch angles. Collectively, our findings provide new insights into the molecular regulation of peanut LBA and present genetic materials for breeding peanut cultivars with ideotypes. [ABSTRACT FROM AUTHOR]

Systemin, the first peptide hormone identified in plants, was initially isolated from tomato (Solanum lycopersicum) leaves. Systemin mediates local and systemic wound‐induced defense responses in plants, conferring resistance to necrotrophic fungi and herbivorous insects. Systemin is recognized by the leucine‐rich‐repeat receptor‐like kinase (LRR‐RLK) receptor SYSTEMIN RECEPTOR1 (SYR1), but how the systemin recognition signal is transduced to intracellular signaling pathways to trigger defense responses is poorly understood. Here, we demonstrate that SERK family LRR‐RLKs function as co‐receptors for SYR1 to mediate systemin signal transduction in tomato. By using chemical genetic approaches coupled with engineered receptors, we revealed that the association of the cytoplasmic kinase domains of SYR1 with SERKs leads to their mutual trans‐phosphorylation and the activation of SYR1, which in turn induces a wide range of defense responses. Systemin stimulates the association between SYR1 and all tomato SERKs (SlSERK1, SlSERK3A, and SlSERK3B). The resulting SYR1‐SlSERK heteromeric complexes trigger the phosphorylation of TOMATO PROTEIN KINASE 1B (TPK1b), a receptor‐like cytoplasmic kinase that positively regulates systemin responses. Additionally, upon association with SYR1, SlSERKs are cleaved by the Pseudomonas syringae effector HopB1, further supporting the finding that SlSERKs are activated by systemin‐bound SYR1. Finally, genetic analysis using Slserk mutants showed that SlSERKs are essential for systemin‐mediated defense responses. Collectively, these findings demonstrate that the systemin‐mediated association of SYR1 and SlSERKs activates defense responses against herbivorous insects. [ABSTRACT FROM AUTHOR]

Salt stress can adversely affect global agricultural productivity, necessitating innovative strategies to mitigate its adverse effects on plant growth and yield. This study investigated the effects of exogenous salicylic acid (SA), grafting (G), and their combined application (GSA) on various parameters in tomato plants subjected to salt stress. The analysis focused on growth characteristics, photosynthesis, osmotic stress substances, antioxidant enzyme activity, plant hormones, ion content, and transcriptome profiles. Salt stress severely inhibits the growth of tomato seedlings. However, SA, G, and GSA improved the plant height by 22.5%, 26.5%, and 40.2%; the stem diameter by 11.0%, 26.0%, and 23.7%; the shoot fresh weight by 76.3%, 113.2%, and 247.4%; the root fresh weight by 150.9%, 238.6%, and 286.0%; the shoot dry weight by 53.5%, 65.1%, and 162.8%; the root dry weight by 150.0%, 150.0%, and 166.7%, and photosynthesis by 4.0%, 16.3%, and 32.7%, with GSA presenting the most pronounced positive effect. Regarding the osmotic stress substances, the proline content increased significantly by more than 259.2% in all treatments, with the highest levels in GSA. Under salt stress, the tomato seedlings accumulated high Na+ levels; the SA, G, and GSA treatments enhanced the K+ and Ca2+ absorption while reducing the Na+ and Al3+ levels, thereby alleviating the ion toxicity. The transcriptome analysis indicated that SA, G, and GSA influenced tomato growth under salt stress by regulating specific signaling pathways, including the phytohormone and MAPK pathways, which were characterized by increased endogenous SA and decreased ABA content. The combined application of grafting and exogenous SA could be a promising strategy for enhancing plant tolerance to salt stress, offering potential solutions for sustainable agriculture in saline environments. [ABSTRACT FROM AUTHOR]

Exogenous brassinolide (BR) and strigolactones (SLs) play an important role in alleviating salt stress in maize. We studied the morphological and physiological responses of the salt-sensitive genotype PH4CV and salt-tolerant genotype Zheng58 to BR (1.65 nM), SL (1 µM), and BS (1.65 nM BR + 1 µM SL) under salt stress. Phenotypic analysis showed that salt stress significantly inhibited the growth of maize seedlings and significantly increased the content of Na+ in the roots. Exogenous hormones increased oxidase activity and decreased Na+ content in the roots and mitigated salt stress. Transcriptome analysis showed that the interaction of BR and SL is involved in photosynthesis–antenna proteins, the TCA cycle, and plant hormone signal transduction pathways. This interaction influences the expression of chlorophyll a/b-binding protein and glucose-6-phosphate isomerase 1 chloroplastic, and aconitase genes are affected. Furthermore, the application of exogenous hormones regulates the expression of genes associated with the signaling pathways of cytokinin (CK), gibberellins (GA), auxin (IAA), brassinosteroid (BR), abscisic acid (ABA), and jasmonic acid (JA). Additionally, exogenous hormones inhibit the expression of the AKT2/3 genes, which are responsible for regulating ion transduction and potassium ion influx. Four candidate genes that may regulate the seedling length of maize were screened out through WGCNA. Respective KOG notes concerned inorganic ion transport and metabolism, signal transduction mechanisms, energy production and conversion, and amino acid transport and metabolism. The findings of this study provide a foundation for the proposition that BR and SL can be employed to regulate salt stress alleviation in maize. [ABSTRACT FROM AUTHOR]

The plant-specific IDD transcription factors (TFs) are vital for regulating plant growth and developmental processes. However, the characteristics and biological roles of the IDD gene family in tomato (Solanum lycopersicum) are still largely unexplored. In this study, 17 SlIDD genes were identified in the tomato genome and classified into seven subgroups according to the evolutionary relationships of IDD proteins. Analysis of exon–intron structures and conserved motifs reflected the evolutionary conservation of SlIDDs in tomato. Collinearity analysis revealed that segmental duplication promoted the expansion of the SlIDD family. Ka/Ks analysis indicated that SlIDD gene orthologs experienced predominantly purifying selection throughout evolution. The analysis of cis-acting elements revealed that the promoters of SlIDD genes contain numerous elements associated with light, plant hormones, and abiotic stresses. The RNA-seq data and qRT-PCR experimental results showed that the SlIDD genes exhibited tissue-specific expression. Additionally, Group A members from Arabidopsis thaliana and rice are known to play a role in regulating plant shoot gravitropism. QRT-PCR analysis confirmed that the expression level of SlIDD15 in Group A was high in the hypocotyls and stems. Subcellular localization demonstrated that the SlIDD15 protein was localized in the nucleus. Surprisingly, the loss-of-function of SlIDD15 by CRISPR/Cas9 gene editing technology did not display obvious gravitropic response defects, implying the existence of functional redundant factors within SlIDD15. Taken together, this study offers foundational insights into the tomato IDD gene family and serves as a valuable guide for exploring their molecular mechanisms in greater detail. [ABSTRACT FROM AUTHOR]

Plant stomata play a crucial role in photosynthesis by regulating transpiration and gas exchange. Meanwhile, environmental cues can also affect the formation of stomata. Stomatal formation, therefore, is optimized for the survival and growth of the plant despite variable environmental conditions. To adapt to environmental conditions, plants open and close stomatal pores and even regulate the number of stomata that develop on the epidermis. There are great differences in the leaf structure and developmental origin of the cell in the leaf between Arabidopsis and grass plants. These differences affect the fine regulation of stomatal formation due to different plant species. In this paper, a comprehensive overview of stomatal formation and the molecular networks and genetic mechanisms regulating the polar division and cell fate of stomatal progenitor cells in dicotyledonous plants such as Arabidopsis and Poaceae plants such as Oryza sativa and Zea mays is provided. The processes of stomatal formation mediated by plant hormones and environmental factors are summarized, and a model of stomatal formation in plants based on the regulation of multiple signaling pathways is outlined. These results contribute to a better understanding of the mechanisms of stomatal formation and epidermal morphogenesis in plants and provide a valuable theoretical basis and gene resources for improving crop resilience and yield traits. [ABSTRACT FROM AUTHOR]

Carotenoid cleavage oxygenases (CCOs) cleave carotenoid molecules to produce bioactive products that influence the synthesis of hormones such as abscisic acid (ABA) and strigolactones (SL), which regulate plant growth, development, and stress adaptation. Here, to explore the molecular characteristics of all members of the OsCCO family in rice, fourteen OsCCO family genes were identified in the genome-wide study. The results revealed that the OsCCO family included one OsNCED and four OsCCD subfamilies. The OsCCO family was phylogenetically close to members of the maize ZmCCO family and the Sorghum SbCCO family. A collinearity relationship was observed between OsNCED3 and OsNCED5 in rice, as well as OsCCD7 and OsNCED5 between rice and Arabidopsis, Sorghum, and maize. OsCCD4a and OsCCD7 were the key members in the protein interaction network of the OsCCO family, which was involved in the catabolic processes of carotenoids and terpenoid compounds. miRNAs targeting OsCCO family members were mostly involved in the abiotic stress response, and RNA-seq data further confirmed the molecular properties of OsCCO family genes in response to abiotic stress and hormone induction. qRT-PCR analysis showed the differential expression patterns of OsCCO members across various rice organs. Notably, OsCCD1 showed relatively high expression levels in all organs except for ripening seeds and endosperm. OsNCED2a, OsNCED3, OsCCD1, OsCCD4a, OsCCD7, OsCCD8a, and OsCCD8e were potentially involved in plant growth and differentiation. Meanwhile, OsNCED2a, OsNCED2b, OsNCED5, OsCCD8b, and OsCCD8d were associated with reproductive organ development, flowering, and seed formation. OsNCED3, OsCCD4b, OsCCD4c, OsCCD8b, and OsCCD8c were related to assimilate transport and seed maturation. These findings provide a theoretical basis for further functional analysis of the OsCCO family. [ABSTRACT FROM AUTHOR]

Summary: Leaf senescence is a complex process regulated by developmental and environmental factors, and plays a pivotal role in the development and life cycle of higher plants. Casein kinase 1 (CK1) is a highly conserved serine/threonine protein kinase in eukaryotes and functions in various cellular processes including cell proliferation, light signaling and hormone effects of plants. However, the biological function of CK1 in plant senescence remains unclear.Through systemic genetic and biochemical studies, we here characterized the function of Arabidopsis EL1‐like (AEL), a CK1, in promoting leaf senescence by stimulating ethylene biosynthesis through phosphorylating transcription factor WRKY22. Seedlings lacking or overexpressing AELs presented delayed or accelerated leaf senescence, respectively.AELs interact with and phosphorylate WRKY22 at Thr57, Thr60 and Ser69 residues to enhance whose transactivation activity. Being consistent, increased or suppressed phosphorylation of WRKY22 resulted in the promoted or delayed leaf senescence. WRKY22 directly binds to promoter region and stimulates the transcription of 1‐amino‐cyclopropane‐1‐carboxylate synthase 7 gene to promote ethylene level and hence leaf senescence.Our studies demonstrated the crucial role of AEL‐mediated phosphorylation in regulating ethylene biosynthesis and promoting leaf senescence by enhancing WRKY22 transactivation activity, which helps to elucidate the fine‐controlled ethylene biosynthesis and regulatory network of leaf senescence. See also the Commentary on this article by Mei & Wang, 244: 5–6. [ABSTRACT FROM AUTHOR]

Phytohormones promote growth in the vegetative phase, flowering and fruit development. A novel class of PGR comprises brassinosteroids (BRs) and polyamines (PAs). In fruit crops, fruit drop at the maturity stage is controlled by the external application of BRs and PAs. BRs such as brassinolide, 24-epibrassinolide and 28-homobrassinolide and PAs such as putrescine, spermidine and spermine play significant roles in plant growth and development. Brassinolide provides tolerance against biotic and abiotic stresses. 24-Epibrassinolide promotes blossoming, fruit retention, fruit set and fruit growth. 28-homobrassinolide promotes cell division and cell elongation. Putrescine enhances seed germination and adventitious root formation in seedlings. Moreover, spermidine provides tolerance against drought and salinity. Furthermore, spermine promotes flowering and fruiting and competes with ethylene precursors. It would be beneficial to apply plant growth regulators such as BRs and PAs to increase fruit yield and quality. This review discusses how phytohormone (BR and PA) application can improve the productivity, quality, physiological, biochemical and postharvest aspects of some tropical, subtropical and temperate fruits and focuses on research areas such as the mode of action and stage of application of BRs and PAs which enhance the yield and quality of these perishable fruit crops. Article highlights: The newly emerged plant growth hormones brassinosteroids and polyamines are vital PGRs for the cultivation of horticulture commodities. BRs and PAs are environmentally safe phytohormones that improve the yield and quality of fruits. These materials are effectively utilized in both fruit production and postharvest management. [ABSTRACT FROM AUTHOR]

Background: Root plays an important role in the growth and development of fruit trees; however, the molecular mechanisms behind the differences among rootstock varie-ties remain unclear. Methods: This study examined the effects of different rootstocks on root structure and the endogenous hormone content of 1-year old apple seedlings in combinations of Tianhong 2 (T2)/Malus robusta (HT), T2/G935, and T2/Jizhen 2 (J2). Results: The results showed that the T2/HT treatment had greater root length, surface area, volume, average diameter, tips and forks, followed by G935 and J2. In T2/HT leaves and roots, the indole-3-acetic acid (IAA) and gibberellins (GA3) levels were highest, and the abscisic acid (ABA) levels were the lowest. A root transcriptome analysis detected 10,064, 10,511, and 8,719 differentially expressed genes in T2/HT vs. T2/G935, T2/HT vs. T2/J2, and T2/J2 vs. T2/G935, respectively. The analysis of Gene Ontology (GO) terms indicated a significant enrichment in biological processes, cellular components, and molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that plant hormone signaling, MAPK signaling pathway–plant, and plant–pathogen interaction played important roles in differences in the rooting ability of different rootstocks. In addition, some key differential genes were associated with root growth and development and were involved in these metabolic pathways. This study is important for enriching theoretical studies of fruit tree roots. [ABSTRACT FROM AUTHOR]

The unscientific application of nitrogen (N) fertilizer not only increases the economic input of pear growers but also leads to environmental pollution. Improving plant N use efficiency (NUE) is the most effective economical method to solve the above problems. The absorption and utilization of N by plants is a complicated process. Glutamine synthetase (GS) and glutamate synthase (GOGAT) are crucial for synthesizing glutamate from ammonium in plants. However, their gene family in pears has not been documented. This study identified 29 genes belonging to the GS and GOGAT family in the genomes of Pyrus betulaefolia (P.be, 10 genes), Pyrus pyrifolia (P.py, 9 genes), and Pyrus bretschneideri (P.br, 10 genes). These genes were classified into two GS subgroups (GS1 and GS2) and two GOGAT subgroups (Fd–GOGAT and NADH–GOGAT). The similar exon–intron structures and conserved motifs within each cluster suggest the evolutionary conservation of these genes. Meanwhile, segmental duplication has driven the expansion and evolution of the GS and GOGAT gene families in pear. The tissue–specific expression dynamics of PbeGS and PbeGOGAT genes suggest significant roles in pear growth and development. Cis–acting elements of the GS and GOGAT gene promoters are crucial for plant development, hormonal responses, and stress reactions. Furthermore, qRT–PCR analysis indicated that PbeGSs and PbeGOGATs showed differential expression under exogenous hormones (GA3, IAA, SA, ABA) and abiotic stress (NO3− and salt stress). In which, the expression of PbeGS2.2 was up–regulated under hormone treatment and down–regulated under salt stress. Furthermore, physiological experiments demonstrated that GA3 and IAA promoted GS, Fd–GOGAT, and NADH–GOGAT enzyme activities, as well as the N content. Correlation analysis revealed a significant positive relationship between PbeGS1.1, PbeGS2.2, PbeNADH–GOGATs, and the N content. Therefore, PbeGS1.1, PbeGS2.2, and PbeNADH–GOGATs could be key candidate genes for improving NUE under plant hormone and abiotic stress response. To the best of our knowledge, our study provides valuable biological information about the GS and GOGAT family in the pear for the first time and establishes a foundation for molecular breeding aimed at developing high NUE pear rootstocks. [ABSTRACT FROM AUTHOR]

Sinopodophyllum hexandrum (Royle) Ying, an endangered perennial medicinal herb, exhibits morpho-physiological dormancy in its seeds, requiring cold stratification for germination. However, the precise molecular mechanisms underlying this transition from dormancy to germination remain unclear. This study integrates transcriptome and plant hormone-targeted metabolomics techniques to unravel these intricate molecular regulatory mechanisms during cold stratification in S. hexandrum seeds. Significant alterations in the physicochemical properties (starch, soluble sugars, soluble proteins) and enzyme activities (PK, SDH, G-6-PDH) within the seeds occur during stratification. To characterize and monitor the formation and transformation of plant hormones throughout this process, extracts from S. hexandrum seeds at five stratification stages of 0 days (S0), 30 days (S1), 60 days (S2), 90 days (S3), and 120 days (S4) were analyzed using UPLC-MS/MS, revealing a total of 37 differential metabolites belonging to seven major classes of plant hormones. To investigate the biosynthetic and conversion processes of plant hormones related to seed dormancy and germination, the transcriptome of S. hexandrum seeds was monitored via RNA-seq, revealing 65,372 differentially expressed genes associated with plant hormone synthesis and signaling. Notably, cytokinins (CKs) and gibberellins (GAs) exhibited synergistic effects, while abscisic acid (ABA) displayed antagonistic effects. Furthermore, key hub genes were identified through integrated network analysis. In this rigorous scientific study, we systematically elucidate the intricate dynamic molecular regulatory mechanisms that govern the transition from dormancy to germination in S. hexandrum seeds during stratification. By meticulously examining these mechanisms, we establish a solid foundation of knowledge that serves as a scientific basis for facilitating large-scale breeding programs and advancing the artificial cultivation of this highly valued medicinal plant. [ABSTRACT FROM AUTHOR]

Ginkgo biloba, usually referred to as a "living fossil," is widely planted in many countries because of its medicinal value and beautiful appearance. Owing to ginkgo's high resistance to drought stress, ginkgo seedlings can even survive withholding water for several days without exhibiting leaf wilting and desiccation. To assess the physiological and transcriptomic mechanisms involved in the drought stress and re-watering responses of Ginkgo biloba, ginkgo seedlings were subjected to drought treatment for 15 d (D_15 d) and 22 d (D_22 d) until they had severely wilted, followed by re-watering for 3 d (D_Re3 d) to restore normal growth. Variations in physiological characteristics (relative water content, malondialdehyde (MDA) content, stomatal aperture, and antioxidant enzyme activity) during drought and re-watering were assessed. In total, 1692, 2031, and 1038 differentially expressed genes (DEGs) were upregulated, while 1691, 2820, and 1910 were downregulated in D_15 d, D_22 d, and D_Re3 d, respectively, relative to the control. Three pathways, namely, plant hormone signal transduction, plant–pathogen interaction, and the plant MAPK signaling pathway, were enriched during drought stress and re-watering. The DEGs involved in plant hormone signal transduction pathways (those of IAA, CTK, GA, ABA, ETH, BR, SA, and JA) and the major differentially expressed transcription factors (TFs; MYB, bHLH, AP2/ERF, NAC, WRKY, and bZIP) were identified. Quantitative real-time PCR revealed six TFs as positive or negative regulators of drought stress response. These phenotype-related physiological characteristics, DEGs, pathways, and TFs provide valuable insights into the drought stress and re-watering responses in G. biloba. [ABSTRACT FROM AUTHOR]

The regulation of vital plant activities by hormones is governed by a family of macromolecular peptides referred to as GH3 genes. This work analyzed the expression patterns of GH3 family genes in pear tissues using transcriptome data and bioinformatics analysis. In the Bai Li pear genome, a total of 18 PbGH3 genes were identified. Comparative evolutionary studies have shown a strong association between PbGH3 and AtGH3 class I and class II proteins. The role of PbGH3 genes in growth activities and hormone regulation was revealed using gene ontology (GO) and promoter region analysis. In addition, although certain PbGH3 genes exhibited tissue-specific expression in sepals, the majority had a ubiquitous expression across all tissues. Bioinformatics and expression studies suggest that the GH3 gene family in pears may have a role in controlling the abscission of the fruit's sepals. This work sheds light on the pear fruit sepal shedding process and may inspire further research. [ABSTRACT FROM AUTHOR]

Fruit ripening represents a multifaceted biological process intricately controlled by an array of plant hormones, transcription factors, and epigenetic modifications. These regulatory mechanisms are crucial in determining fruit quality and post-harvest shelf life. Recent advancements in proteomics have shifted the focus toward understanding protein post-translational modifications (PTMs), which play a crucial role in modulating protein function. PTMs enhance protein activity and stability by altering their properties after biosynthesis, thereby adding an additional layer of regulation to the ripening process. This paper provides a comprehensive review of the roles of PTMs, including ubiquitination, phosphorylation, redox modifications, and glycosylation in regulating fruit ripening. Emphasis is placed on the intricate interplay between these PTMs and key regulator factors such as plant hormones, transcriptional mechanisms, and epigenetic modifications. By exploring these interactions, this review seeks to enhance our understanding of the complex regulatory network underlying fruit ripening and to offer novel perspectives on strategies for fruit preservation. [ABSTRACT FROM AUTHOR]

Drought stress, as one of the most common environmental factors, seriously affects seed- ling establishment as well as plant growth and productivity. The growth of Toona ciliata is constrained by soil moisture deficit, and drought stress can reduce its productivity and limit its suitable growing environment. To explore the molecular mechanism of Toona ciliata responding to drought stress, leaves of two-year-old Toona ciliata seedlings were used as experimental materials for transcriptome sequencing and physiological index measurements. Under drought stress, the contents of Chl, MDA, POD, SP, SS, and RWC all change differently. We performed transcriptome sequencing, obtaining 4830 differential genes. The enrichment analysis indicates that the primary effects on the leaves of Toona ciliata under drought stress are related to photosynthesis and responses to plant hormone signal transduction. Transcription factor families associated with drought resistance include the NAC, WRKY, bZIP, bHLH, AP2-EREBP, C3H, GRAS, and FRAI transcription factor families. A weighted gene co-expression network analysis (WGCNA) analysis successfully identified 10 hub genes in response to drought stress in Toona ciliata leaves. Real-time quantitative PCR (RT-qPCR) validated the reliability of the transcriptomic data, and the analysis of its results showed a close correlation with the data obtained from RNA-seq. This study clarifies the transcriptional response of Toona ciliata to drought stress, contributing to the revelation of the molecular mechanisms of drought adaptation. [ABSTRACT FROM AUTHOR]

Terpene synthases (TPSs) are crucial for the diversification of terpenes, catalyzing the formation of a wide variety of terpenoid compounds. However, genome-wide systematic characterization of TPS genes in Cymbidium ensifolium has not been reported. Within the genomic database of C. ensifolium, we found 30 CeTPS genes for this investigation. CeTPS genes were irregularly distributed throughout the seven chromosomes and primarily expanded through tandem duplications. The CeTPS proteins were classified into three TPS subfamilies, including 17 TPS-b members, 8 TPS-a members, and 5 TPS-c members. Conserved motif analysis showed that most CeTPSs contained DDxxD and RRX8W motifs. Cis-element analysis of CeTPS gene promoters indicated regulation primarily by plant hormones and stress. Transcriptome analysis revealed that CeTPS1 and CeTPS18 had high expression in C. ensifolium flowers. qRT-PCR results showed that CeTPS1 and CeTPS18 were predominantly expressed during the flowering stage. Furthermore, CeTPS1 and CeTPS18 proteins were localized in the chloroplasts. These results lay the theoretical groundwork for future research on the functions of CeTPSs in terpenoid biosynthesis. [ABSTRACT FROM AUTHOR]

Clubroot disease, caused by the pathogen Plasmodiophora brassicae, is a serious disease that poses a critical threat to cabbage production. However, the molecular mechanism of the microRNAs (miRNAs) involved in the cabbage's response to P. brassicae infection remains to be elucidated. Here, the mRNA and miRNA expression profiles of cabbage in response to a P. brassicae infection were analyzed. In the transcriptome analysis, 2217 and 5552 differentially expressed genes (DEGs) were identified at 7d and 21d after inoculation, which were enriched in MAPK signaling, plant–pathogen interaction, plant hormone signal transduction, and phenylpropanoid biosynthesis pathways. BolC02g057640.2J, BolC09g006890.2J, BolC02g013230.2J, BolC06g006490.2J, BolC03g052660.2J, BolC07g052580.2J, and BolC04g044910.2J were predicted to be significantly involved in the defense response or plant–pathogen interaction through co-expression network analysis. Small RNA data analysis identified 164 miRNAs belonging to 51 families. miR1515, miR166, miR159, and miR9563 had the greatest number of members among the miRNA families. Integrated analysis revealed 23 miRNA–mRNA interactions related to a P. brassicae infection. The target genes of differentially expressed miRNAs (DEMs) revealed the NAC, ARF, TCP, and SPL transcription factor members that probably participate in the defense response. This study provided new insights into the miRNA-involved regulatory system during the process of disease infection with P. brassicae in cabbage. [ABSTRACT FROM AUTHOR]

To assess the regulatory mechanisms involved in the transcriptomic response of Ginkgo biloba to water shock and rehydration, ginkgo seedlings were subjected to dehydration for 0, 3, 6, 12, and 24 h, followed by rehydration for 12 h (Re12 h). A total of 1388, 1802, 2267, 2667, and 3352 genes were upregulated, whereas 1604, 1839, 1934, 2435, and 3035 genes were downregulated, at 3, 6, 12, 24, and Re12 h, respectively, compared to 0 h. Two KEGG pathways—the plant pathogen interaction pathway and mitogen-activated protein kinase (MAPK) signaling pathway—were enriched under water shock but not under rehydration. Moreover, plant hormone signal transduction was enriched under both water shock and rehydration. Differentially expressed genes (DEGs) involved in the ABA signaling pathway (PYR/PYLs, PP2Cs, and SnRK2s) and major differentially expressed transcription factors (MYB, bHLH, AP2/ERF, NAC, WRKY, and bZIP TFs) were identified. qRT-PCR analysis further revealed GbWRKY3 as a negative regulator of the water shock response in G. biloba. The subcellular localization results revealed GbWRKY3 as a nuclear protein. These phenotype-related DEGs, pathways, and TFs provide valuable insight into the water shock and rehydration response in G. biloba. [ABSTRACT FROM AUTHOR]

ADP-glucose pyrophosphorylase (AGPase), which is a key enzyme in the starch biosynthesis pathway, plays a critical role in barley grain development. Despite its importance, the regulatory mechanisms governing AGPase expression, particularly the influence of plant hormones, remain poorly understood in barley. To address this, we identified and characterized the HvAGPS2b gene, which encodes the AGPase small subunit. The full-length HvAGPS2b gene was cloned from the barley database and expressed as a recombinant protein using the pET-30a system. Polyclonal antibodies were prepared against HvAGPS2b to facilitate detailed analysis. Our findings revealed that HvAGPS2b, as a small subunit of the rate-limiting enzyme AGPase, is integral to the later stages of grain development. Furthermore, RT-qPCR and Western blotting analyses showed that the phytohormones ABA, GA, ETH, and BR significantly upregulated the expression of AGPase small subunits. These results underscore the vital role of plant hormones in modulating AGPS2b expression, thereby influencing grain development. This study provides significant insights into the hormonal regulation of starch biosynthesis and establishes a foundation for further investigation into the functional dynamics of AGPase in barley. [ABSTRACT FROM AUTHOR]

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Phytohormones are signaling substances that control essential elements of growth, development, and reactions to environmental stress. Drought, salt, heat, cold, and floods are a few examples of abiotic factors that have a significant impact on plant development and survival. Complex sensing, signaling, and stress response systems are needed for adaptation and tolerance to such pressures. Abscisic acid (ABA) is a key phytohormone that regulates stress responses. It interacts with the jasmonic acid (JA) and salicylic acid (SA) signaling pathways to direct resources toward reducing the impacts of abiotic stressors rather than fighting against pathogens. Under exposure to nanoparticles, the plant growth hormones also function as molecules that regulate stress and are known to be involved in a variety of signaling cascades. Reactive oxygen species (ROS) are detected in excess while under stress, and nanoparticles can control their formation. Understanding the way these many signaling pathways interact in plants will tremendously help breeders create food crops that can survive in deteriorating environmental circumstances brought on by climate change and that can sustain or even improve crop production. Recent studies have demonstrated that phytohormones, such as the traditional auxins, cytokinins, ethylene, and gibberellins, as well as more recent members like brassinosteroids, jasmonates, and strigolactones, may prove to be significant metabolic engineering targets for creating crop plants that are resistant to abiotic stress. In this review, we address recent developments in current understanding regarding the way various plant hormones regulate plant responses to abiotic stress and highlight instances of hormonal communication between plants during abiotic stress signaling. We also discuss new insights into plant gene and growth regulation mechanisms during stress, phytohormone engineering, nanotechnological crosstalk of phytohormones, and Plant Growth-Promoting Rhizobacteria's Regulatory Powers (PGPR) via the involvement of phytohormones. [ABSTRACT FROM AUTHOR]

Introduction: The thickening of radish taproots is primarily determined by secondary growth driven by the vascular cambium and is a highly intricate process regulated by plant hormones, transcription factors, and many metabolic pathways. Gibberellin (GA), a plant hormone associated with cell elongation, is essential in secondary growth. However, the mechanism through which exogenous GA3 regulates secondary taproot growth in radishes remains unclear. Methods: Integrated morphological, anatomical, hormonal, and transcriptomic analyses of taproots in radishes treated with GA3 and its biosynthesis inhibitor paclobutrazol (PBZ) were performed to explore their effects on taproot secondary growth and key regulatory pathways. Results: GA3 significantly hindered taproot thickening by inhibiting the formation and maintenance of the vascular cambium, and PBZ promoted root development by increasing root length rather than root diameter. Transcriptome analysis revealed 2,014, 948, and 1,831 differentially expressed genes identified from the control vs. GA3, control vs. PBZ, and GA3 vs. PBZ comparisons, respectively. Kyoto Encyclopedia of Genes and Genome pathway enrichment analysis revealed that differentially expressed genes were primarily involved in the biosyntheses of secondary metabolites and metabolic pathways. GA3 significantly increased the levels of endogenous indole-acetic acid and the expression of auxin synthesis and signal transduction genes. Discussion: Exogenous GA3 significantly inhibited the expression of genes involved in the maintenance and differentiation of vascular cambium, including WOX14, ER/ERL1, and XCP2. Exogenous GA3 affects root thickening in radishes primarily by regulating hormone signal transduction pathways, vascular cambium activity, and substance and energy metabolisms. Our findings provide insights into the mechanisms underlying taproot thickening in radishes and provide a valuable gene database for future studies. [ABSTRACT FROM AUTHOR]

Pythium sensu lato (s.l.) is a genus of parasitic oomycetes that poses a serious threat to agricultural production worldwide, but their severity is often neglected because little knowledge about them is available. Using an internal transcribed spacer (ITS) amplicon-based-metagenomics approach, we investigate the occurrence, abundance, and diversity of Pythium spp. s.l. in 127 corn fields of 11 European countries from the years 2019 to 2021. We also identify 73 species, with up to 20 species in a single soil sample, and the prevalent species, which show high species diversity, varying disease potential, and are widespread in most countries. Further, we show species-species co-occurrence patterns considering all detected species and link species abundance to soil parameter using the LUCAS topsoil dataset. Infection experiments with recovered isolates show that Pythium s.l. differ in disease potential, and that effective interference with plant hormone networks suppressing JA (jasmonate)-mediated defenses is an essential component of the virulence mechanism of Pythium s.l. species. This study provides a valuable dataset that enables deep insights into the structure and species diversity of Pythium s.l. communities in European corn fields and knowledge for better understanding plant-Pythium interactions, facilitating the development of an effective strategy to cope with this pathogen. Pythium sensu lato (s.l.) is an oomycete that poses a serious threat to agricultural production worldwide. This study, using metabarcoding, provides insights into the diverse soil communities of Pythium s.l. across 127 locations and their disease potential in European corn fields. [ABSTRACT FROM AUTHOR]