Aug 2026· Science Advances· Vol 12· 0 citations· 67 references
Medicine
TL;DR
It is shown that salt stress–induced ABA accumulation up-regulates Heat Shock Factor 4 (CmHSFA4), a gene that is known to enhance chrysanthemum salt tolerance, and an ABA-SnRK2.2-ABF1/BRM signaling module that integrates phosphorylation-dependent protein stabilization and degradation with histone methylation dynamics to fine-tune salt stress–responsive gene expression in chrysanthemum is revealed.
Abstract
Soil salinization poses a major threat to global agricultural productivity and plant biodiversity. The phytohormone abscisic acid (ABA) is central to plant adaptation to abiotic stress; however, the mechanisms by which ABA coordinates posttranslational modifications of signaling proteins with epigenetic regulation remain poorly understood. Here, we show that salt stress–induced ABA accumulation up-regulates Heat Shock Factor 4 (CmHSFA4), a gene that is known to enhance chrysanthemum salt tolerance. The ABA responsive transcription factor ABRE binding factor 1 (CmABF1) binds to the CmHSFA4 promoter to activate its expression and also recruits the chromatin remodeler BRAHMA (CmBRM) to repress transcription by limiting H3 lysine-4 trimethylation (H3K4me3) deposition. We further demonstrate that the ABA-activated sucrose non-fermenting-1-related protein kinase 2.2 (CmSnRK2.2) phosphorylates and stabilizes CmABF1, while concurrently phosphorylating and promoting CmBRM degradation under salt stress. This dual regulation enhances H3K4me3 enrichment at the CmHSFA4 promoter, thereby inducing its transcription and conferring salt tolerance. Together, our findings reveal an ABA-SnRK2.2-ABF1/BRM signaling module that integrates phosphorylation-dependent protein stabilization and degradation with histone methylation dynamics to fine-tune salt stress–responsive gene expression in chrysanthemum.
Low temperature is a common abiotic stress in the early spring and winter cultivation of oriental melons, which seriously affects their normal growth and development, and plants can activate the defence mechanism related to reactive oxygen species through secondary metabolic pathways. Cucurbitacins are a defensive secondary metabolite that produces a bitter taste in Cucurbitaceae plants. However, the molecular regulatory mechanism between low temperature and biosynthesis of cucurbitacins, as well as whether cucurbitacins will enhance the plant's resistance to cold stress, has not been studied yet. In this study, cucurbitacin B (CuB) content in oriental melon seedlings increased under low-temperature treatment at 10°C; the CuB biosynthetic genes and abscisic acid-responsive element binding factor 1 (CmABF1) was significantly induced to express 1 day after treatment. Through analyzing the promoters of CuB biosynthetic genes and conducting various transcriptional activation experiments, it was found that CmABF1 could bind to and activate the promoters of CmBi, Cm160, Cm170, Cm180 and CmACT, respectively, and positively regulates their expression. Furthermore, CmABF1 interacted with bitterness-specific transcription factors (CmBt/CmBr) in leaves/roots at the protein level and engaged in regulating CuB biosynthesis in response to cold stress. More importantly, we found exogenous spraying of CuB can alleviate the low-temperature stress injury of melon and tomato seedlings. In brief, our research has identified the specific molecular mechanisms by which the CmABF1-CmBt/CmBr modules regulate CuB biosynthesis in response to cold stress. This study clarified the interrelationship between low temperature and CuB biosynthesis, explored a new way to alleviate the abiotic stress injury of seedlings, which is of great significance for the early seedling development of oriental melons.
Yushan Huang, Haoxiong Tang, Fei Luo et al.· Plant, Cell and Environment· 0 citations
Pepper (Capsicum annuum L.) exhibits a pronounced sensitivity to salt stress, making it crucial to investigate the genetic mechanisms that confer salt tolerance. The MYB transcription factor family is pivotal in mediating plant growth and responses to environmental stresses. However, the specific involvement of MYB in pepper responses to salinity remain largely uncharacterized. In this work, we identified CaMYB30 as a crucial regulator of pepper's response to salt stress. Additionally, we discovered that CaMYB30 can directly bind to the CaWRKY29 gene promoters and positively activate its expression. Silencing either CaMYB30 or CaWRKY29 resulted in heightened sensitivity to salinity stress, as evidenced by increased electrolyte leakage and elevated Na+/K+ ratios. Furthermore, we demonstrated that the CaMYB30-CaWRKY29 module played a role in regulating reactive oxygen species (ROS) homeostasis by modulating the activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) enzymes. Collectively, our findings provided essential insights into the regulatory role of the CaMYB30-CaWRKY29 module in the context of pepper salt stress, establishing a foundation for subsequent functional validation and genetic engineering applications.
Liping Qiu, Huibin Han, Yue Wang et al.· Plant Science· 0 citations
Cold stress ranks among the notable abiotic stresses that significantly hinder plant growth and geographical distribution. Brassinosteroids (BRs) have been proven to enhance the cold tolerance of plants across multiple species. However, the involvement of BR and its regulatory mechanism underlying cold tolerance in chrysanthemum has not yet been fully elucidated. In this study, we found that BR treatment alleviated cold stress-induced growth inhibition in chrysanthemum. Based on the transcriptome database of Chrysanthemum in response to cold stress, CmBEEL1, a member of the bHLH family genes, was identified and characterized. Both cold stress and BR treatments upregulated the expression of CmBEEL1. We further generated CmBEEL1-overexpressing (CmBEEL1-OX) lines, and found that CmBEEL1-OX lines exhibited enhanced cold tolerance, characterized by reduced electrolyte leakage and lower reactive oxygen species (ROS) accumulation. Weighted gene co-expression network analysis (WGCNA) and downstream gene analysis indicated that CmBEEL1 primarily modulates cold tolerance by inducing alterations in the expression of the ICE - DREB - COR pathway and ROS metabolism. Moreover, CmBEEL1 was shown to directly bind to the promoter of CmICE1, to activate ICE - DREB - COR cascade. It is concluded that overexpression of CmBEEL1 is sufficient to enhance cold tolerance in chrysanthemum via the ICE1 cascade and ROS homeostasis.
Yingning Zheng, Hongfeng Huang, Chunnan Chang et al.· Plant physiology and biochem...· 0 citations
Salt stress poses a threat to plant water and nutrient uptake and leads to multiple forms of damages in plants, making it a major challenge to global crop production. PHYTOCHROME-INTERACTING FACTOR 3 (PIF3) is a key transcription factor in light signaling and it has been reported to play a critical role in plant responses to salt stress. Here, we demonstrated that PIF3 negatively regulates plant salt tolerance in Arabidopsis, and salt stress significantly enhances the interaction between PIF3 and light-activated PHYTOCHROME B (PHYB), leading to accelerated degradation of PIF3 in light, thus alleviating its negative regulation on plant salt tolerance. Additionally, we identified AGAMOUS-LIKE 21 (AGL21) as a downstream target gene of PIF3. PIF3 directly binds to the promoter of the AGL21 gene to promote its expression. The PIF3-AGL21 module transcriptionally modulates the expression a battery of downstream genes, including those involved in redox homeostasis regulation, thereby leading to accumulation of reactive oxygen species (ROS) and disruption of redox homeostasis within plants in response to salt stress. PHYB-mediated degradation of PIF3 attenuates the PIF3-AGL21 module to restore redox homeostasis and enhance plant tolerance to salt stress.
Yiyi Zhang, Xixian Feng, Zhong-Tong Liu et al.· Journal of Experimental Bota...· 0 citations
Soil salinization limits the yield and quality of Dendrobium officinale. The molecular mechanisms linking methyl jasmonate (MeJA) signaling to the biosynthesis of glucomannans (GMs) under salinity remain unclear. In the WGCNA of MeJA- and salinity-treated D. officinale transcriptome, an R2R3-MYB transcription factor was identified, DoMYB41, which was highly expressed in stems and induced by both treatments. Overexpression of DoMYB41 in PLBs increased GMs and anthocyanin, enhanced the activities of antioxidant enzymes, reduced oxidative damage, and elevated relative water content, whereas CRISPR/Cas9 knockout lines showed opposite phenotypes. Transcriptomic analysis identified DoTIP1–1 as a key downstream target, and biochemical assays (dual-LUC, Y1H, EMSA) confirmed that DoMYB41 activates DoTIP1–1 transcription by directly targeting the MBS motif present in its promoter. Furthermore, DoMYB41 physically interacted with the bHLH transcription factor DoMYC2, which alone bound to and activated the promoters of both DoTIP1–1 and DoMYB41, forming a positive feedback loop. Intriguingly, DoMYB41 and DoMYC2 synergistically activated DoTIP1–1. These findings uncovered a MeJA-responsive DoMYB41-DoMYC2 cascade that iteratively activates DoTIP1–1 expression and promotes the biosynthesis of GMs, thereby enhancing salinity tolerance in D. officinale. This study also provides genetic targets for salinity tolerance in breeding programs for this horticultural orchid.
Heat stress is a major environmental constraint limiting the productivity of perennial ryegrass (Lolium perenne), a widely cultivated forage and turfgrass. Here, through a genome-wide association study (GWAS) analysis of a diverse perennial ryegrass population, we identified LpbZIP41 as a major heat tolerance quantitative trait locus (QTL) for heat tolerance. Natural variation at this locus comprises three haplotypes showing differential thermotolerance, with evidence of positive selection during breeding. LpbZIP41 localizes to the nucleus and exhibits rapid heat-inducible expression. Functional validation via CRISPR-Cas9-mediated knockout confirmed that LpbZIP41 is essential for heat stress. Overexpression of LpbZIP41 in perennial ryegrass enhanced thermotolerance, as evidenced by improved survival, reduced lipid peroxidation, maintained membrane integrity, and global transcriptional reprogramming under heat stress. Mechanistically, we uncovered a transcriptional cascade that LpDREB2A directly activates LpbZIP41 transcription by binding to dehydration-responsive element (DRE) motifs in the promoter. LpbZIP41, in turn, regulates LpNCED4, a key abscisic acid (ABA) biosynthesis gene, and LpβCA2, encoding a stress-responsive carbonic anhydrase. Furthermore, LpbZIP66 functions as a negative regulator that antagonizes LpbZIP41 activity via heterodimerization. Collectively, our findings established an LpDREB2A-LpbZIP41/LpbZIP66 regulatory module as a central hub that integrates ABA biosynthesis and metabolic signals to confer heat stress tolerance in a cool-season grass.
Zhengfu Fang, Jie Chen, Simin Wu et al.· The Plant Journal· 0 citations
