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Plant growth‐promoting rhizobacteria (PGPR) are known for their role in ameliorating plant stress, including alkaline stress, yet the mechanisms involved are not fully understood. This study investigates the impact of various inoculum doses of Bacillus licheniformis Jrh14‐10 on Arabidopsis growth under alkaline stress and explores the underlying mechanisms of tolerance enhancement. We found that all tested doses improved the growth of NaHCO3‐treated seedlings, with 109 cfu/mL being the most effective. Transcriptome analysis indicated downregulation of ethylene‐related genes and an upregulation of polyamine biosynthesis genes following Jrh14‐10 treatment under alkaline conditions. Further qRT‐PCR analysis confirmed the suppression of ethylene biosynthesis and signaling genes, alongside the activation of polyamine biosynthesis genes in NaHCO3‐stressed seedlings treated with Jrh14‐10. Genetic analysis showed that ethylene signaling‐deficient mutants (etr1‐3 and ein3‐1) exhibited greater tolerance to NaHCO3 than the wild type, and the growth‐promoting effect of Jrh14‐10 was significantly diminished in these mutants. Additionally, Jrh14‐10 was found unable to produce 1‐aminocyclopropane‐1‐carboxylic acid (ACC) deaminase, indicating it does not reduce the ethylene precursor ACC in Arabidopsis. However, Jrh14‐10 treatment increased the levels of polyamines (putrescine, spermidine, and spermine) in stressed seedlings, with spermidine particularly effective in reducing H2O2 levels and enhancing Fv/Fm under NaHCO3 stress. These findings reveal a novel mechanism of PGPR‐induced alkaline tolerance, highlighting the crosstalk between ethylene and polyamine pathways, and suggest a strategic redirection of S‐adenosylmethionine towards polyamine biosynthesis to combat alkaline stress. [ABSTRACT FROM AUTHOR]

As a well‐conserved histone variant, H2A.Z epigenetically regulates plant growth and development as well as the interaction with environmental factors. However, the role of H2A.Z in response to salt stress remains unclear, and whether nucleosomal H2A.Z occupancy work on the gene responsiveness upon salinity is obscure. Here, we elucidate the involvement of H2A.Z in salt response by analysing H2A.Z disorder plants with impaired or overloaded H2A.Z deposition. The salt tolerance is dramatically accompanied by H2A.Z deficiency and reacquired in H2A.Z OE lines. H2A.Z disorder changes the expression profiles of large‐scale of salt responsive genes, announcing that H2A.Z is required for plant salt response. Genome‐wide H2A.Z mapping shows that H2A.Z level is induced by salt condition across promoter, transcriptional start site (TSS) and transcription ending sites (−1 kb to +1 kb), the peaks preferentially enrich at promoter regions near TSS. We further show that H2A.Z deposition within TSS provides a direct role on transcriptional control, which has both repressive and activating effects, while it is found generally H2A.Z enrichment negatively correlate with gene expression level response to salt stress. This study shed light on the H2A.Z function in salt tolerance, highlighting the complex regulatory mechanisms of H2A.Z on transcriptional activity for yielding appropriate responses to particularly environmental stress. Summary Statement: Arabidopsis H2A.Z is required for plant salt response. H2A.Z deposition near transcriptional start site provides a direct role on transcriptional control, which has both repressive and activating effects, while generally H2A.Z enrichment negatively correlate with gene expression level response to salt stress. [ABSTRACT FROM AUTHOR]

Salt stress severely restricts plant growth and crop production, which is accompanied by accumulation of reactive oxygen species (ROS) that disturb cell redox homeostasis and oxidize redox-sensitive proteins. Eutrema salsugineum, a halophytic species closely related to Arabidopsis, shows a high level of tolerance to salinity and is increasingly used as a model plant in abiotic stress biology. To understand redox modifications and signaling pathways under salt stress, we used tandem mass tag (TMT)-based proteomics to quantify the salt-induced changes in protein redox modifications in E. salsugineum. Salt stress led to increased oxidative modification levels of 159 cysteine sites in 107 proteins, which play roles in carbohydrate and energy metabolism, transport, ROS homeostasis, cellular structure modulation, and folding and assembly. These lists of unknown redox reactive proteins in salt mustard lay the foundation for future research to understand the molecular mechanism of plant salt response. However, glutathione peroxidase (GPX) is one of the most important antioxidant enzymes in plants. Our research indicates that EsGPX may be involved in regulating ROS levels and that plants with overexpressed EsGPX have much improved salt tolerance. [ABSTRACT FROM AUTHOR]

Salt is one of the most important environmental factors in crop growth and development. N6-methyladenosine (m6A) is an epigenetic modification that regulates plant–environment interaction at transcriptional and translational levels. Sugar beet is a salt-tolerant sugar-yielding crop, but how m6A modification affects its response to salt stress remains unknown. In this study, m6A-seq was used to explore the role of m6A modification in response to salt stress in sugar beet (Beta vulgaris). Transcriptome-wide m6A methylation profiles and physiological responses to high salinity were investigated in beet roots. After treatment with 300 mM NaCl, the activities of peroxidase and catalase, the root activity, and the contents of Na+, K+, and Ca2+ in the roots were significantly affected by salt stress. Compared with the control plants, 6904 differentially expressed genes (DEGs) and 566 differentially methylated peaks (DMPs) were identified. Association analysis revealed that 243 DEGs contained DMP, and 80% of these DEGs had expression patterns that were negatively correlated with the extent of m6A modification. Further analysis verified that m6A methylation may regulate the expression of some genes by controlling their mRNA stability. Functional analysis revealed that m6A modifications primarily affect the expression of genes involved in energy metabolism, transport, signal transduction, transcription factors, and cell wall organization. This study provides evidence that a post-transcriptional regulatory mechanism mediates gene expression during salt stress by affecting the stability of mRNA in the root. [ABSTRACT FROM AUTHOR]