It is 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.
Abstract
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.
Submergence and flooding impose severe crop losses through hypoxic stress. The Membrane Attack Complex/Perforin (MACPF) superfamily proteins function as pore-forming effectors in development and immunity across eukaryotic organisms, yet their role in plant hypoxia responses remains largely unexplored. Here, we identify two MACPF proteins in pepper (Capsicum annuum), CaMACPF1 and CaMACPF6, as positive regulators of hypoxia tolerance. CaMACPF1 and CaMACPF6 localize to endoplasmic reticulum-plasma membrane contact sites (EPCS) and the Golgi apparatus, with CaMACPF1 additionally detected in the nucleus and plasma membrane. When either protein was overexpressed, plants showed markedly better endurance under hypoxic stress and submergence, with accumulating less reactive oxygen species (ROS). Both proteins triggered jasmonic acid (JA) biosynthesis under oxygen deprivation, yet only CaMACPF6 specifically redirected auxin metabolism by converting indole-3-pyruvic acid (IPA) to indole-3-lactic acid (ILA). Taken together, these findings suggest that CaMACPF proteins may act as molecular switches linking EPCS dynamics to phytohormone signaling during hypoxic adaptation.
Yi-Xian Guo, Sirui Ma, Yang Yu et al.· Plant physiology and biochem...· 0 citations
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.
Xinhui Wang, Han Wang, Hong-Yu Wei et al.· Science Advances· 0 citations
L-Ascorbic acid (AsA) is a key antioxidant that alleviates oxidative stress in plants. Previous yeast one-hybrid (Y1H) screening identified RrWRKY75 as a transcription factor capable of binding to the promoter of RrGGP2 (GDP-L-galactose pyrophosphatase 2), a key structural gene responsible for massive AsA accumulation in Rosa roxburghii fruit. The function of RrWRKY75 in plant stress responses remains unclear. Here, RrWRKY75 is verified to specifically bind to the RrGGP2 promoter and activate its transcription. This positive regulatory effect on RrGGP2 transcript levels and AsA accumulation is further confirmed through overexpression or silencing of RrWRKY75 in R. roxburghii fruit or callus. Among various abiotic stress conditions, RrWRKY75 expression is significantly induced by salt stress. Upon its overexpression in callus or Arabidopsis thaliana, elevated AsA levels and antioxidant capacity are observed, thereby enhancing salt tolerance. Interestingly, RrWRKY75 also binds to the promoter of RrUNE12, a salt-responsive factor in R. roxburghii, and activates its expression. Moreover, yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays confirm the physical interaction between RrWRKY75 and RrUNE12, which jointly upregulates RrGGP2 expression and AsA production. Collectively, RrWRKY75 boosts AsA biosynthesis and salt tolerance both by directly trans-activating RrGGP2 and by synergizing with RrUNE12 through transcriptional activation and protein complex formation. These findings provide insights into the regulatory role of RrWRKY75 in abiotic stress tolerance and offer valuable genetic resources for R. roxburghii germplasm improvement.
Feng Yang, Qianmin Huang, Wentao Ma et al.· Plant Science· 0 citations
It is concluded that overexpression of CmBEEL1 is sufficient to enhance cold tolerance in chrysanthemum via the ICE1 cascade and ROS homeostasis via the ICE1 cascade and ROS homeostasis.
Yingning Zheng, Hongfeng Huang, Chunnan Chang et al.· Plant physiology and biochem...· 0 citations
Soil salinization represents a significant constraint on global agricultural development. Although several NAC gene families have been implicated in the response to salt stress, the mechanisms underlying salt stress tolerance remain unclear, particularly in perennial fruit trees. In this study, we identify MdJUB1, a NAC transcription factor, as a key regulator of salt stress response in apple. Under salt stress, MdJUB1 increases γ-aminobutyric acid (GABA) content, thereby positively regulating salt stress tolerance in apple. Further analysis using yeast one-hybrid, luciferase assays, and electrophoretic mobility shift assays demonstrated that MdJUB1 directly binds to the promoter of MdGAD1, promoting GABA synthesis. Additionally, under salt stress, overexpression of MdJUB1 increased the Na+/K+ ratio in apple. MdJUB1 also binds to the promoters of MdNHX1, MdHKT1, and MdSOS3, activating their expression. Using yeast two-hybrid screening, we identified MdDOF2.4 as an interactor of MdJUB1 and found that MdDOF2.4 positively regulates salt stress tolerance. Importantly, the interaction between MdDOF2.4 and MdJUB1 enhances the expression of downstream genes, including MdGAD1, MdNHX1, MdHKT1, and MdSOS3. Our results demonstrate that MdJUB1 is involved in the regulation of GABA levels and the maintenance of Na+/K+ homeostasis, which may contribute to enhanced salt tolerance in apple.
Yu-Xing Li, Tan-Fang Liu, Yan-Jiao Shi et al.· Horticulture Research· 0 citations
Osmotic stress severely limits plant growth and agricultural productivity, primarily by disrupting cellular water balance. Although the CBL-CIPK signaling network is recognized as a central mediator of abiotic stress responses, the functions of CiCIPKs from pecan (Carya illinoinensis) in osmotic stress tolerance remain largely unclear. In this study, two osmotic stress-responsive genes, CiCIPK8 and CiCIPK11, were cloned and functionally characterized via heterologous expression in Arabidopsis. Under mannitol-induced osmotic stress, transgenic lines exhibited significantly enhanced seed germination and root elongation compared with the wild-type (WT) plants. Physiological analyses revealed that overexpression of CiCIPK8 and CiCIPK11 improved osmotic stress tolerance by increasing antioxidant enzyme activities, reducing oxidative damage, and promoting the accumulation of compatible osmolytes, including proline, soluble proteins, and soluble sugars. Transcriptomic profiling, combined with quantitative reverse transcription-polymerase chain reaction (qRT-PCR) validation, demonstrated that CiCIPK8 and CiCIPK11 coordinately regulate multiple stress-responsive pathways, including plant hormone signal transduction, mitogen-activated protein kinase (MAPK) cascades, cell wall dynamics, and metabolic regulation. In addition, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays demonstrated that CiCIPK8 interacted with CiCBL1 and CiCBL8, whereas CiCIPK11 specifically interacted with CiCBL1, suggesting the involvement of a Ca2+-dependent CBL-CIPK signaling module. In conclusion, these findings reveal that CiCIPK8 and CiCIPK11 function as positive regulators of osmotic stress tolerance by integrating ROS scavenging, osmotic adjustment, and transcriptional reprogramming. This study provides valuable insights into stress signaling in pecan and offers candidate targets for the molecular breeding of osmotic stress-tolerant woody crops.
Ming-Wei Wang, Hong-Yu Shao, Wei-Hua Jin et al.· Plant physiology and biochem...· 0 citations
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