Plant Physiology and Biochemistry最新文献

Physcomitrium patens (P. patens), a model moss species occupying a unique transitional evolutionary position between aquatic and terrestrial plants, has evolved highly effective mechanisms to cope with heat stress and diverse environmental challenges. Previously, we identified the HDS regulatory module that coordinates thermal adaptation and growth, where MEcPP induces 81.25% of heat priming-competent HSP20 protein isoforms. In this study, we identified 26 HSP20 genes in P. patens, which are classified into three subfamilies (CI, CII, and P/MT). Focusing on the functional characterization of PpHSP17.2B, we found that its overexpression under heat stress enhances chlorophyll fluorescence and chlorophyll content, thereby improving thermal tolerance. Conversely, Pphsp17.2b knockout lines exhibited thermosensitive phenotypes. While the hds2 hds3 double mutant displayed significantly enhanced thermotolerance compared to the wild type (WT), the hds2 hds3 Pphsp17.2b triple mutant lines exhibited heat sensitivity indistinguishable from the Pphsp17.2b single mutant, completely abolished the resistance phenotype of the hds2 hds3 double mutant. This genetic evidence establishes PpHSP17.2B as an essential component downstream of HDS-mediated thermotolerance pathway. Furthermore, these findings expand the HDS module, and provide new insights into plant thermal regulatory networks.

Cabbage (Brassica oleracea var. capitata) is a leafy Brassica vegetable crop whose leaf color and morphology critically influence yield, photosynthetic performance, and market quality. In this study, we identified a natural cabbage mutant, namely, 1180mu, that exhibits virescent-malformed leaves, reduced thylakoid content, decreased fertility, and a relatively low seed-setting rate. Physiological analyses further revealed reduced chlorophyll accumulation, impaired photosynthetic capacity, and stunted growth in 1180mu compared with the wild type (WT). Genetic analysis and map-based cloning demonstrated that BoVML1, a dominant gene homologous to Arabidopsis RER3, is causal; a 44-bp deletion in BoVML1 disrupts its function. CRISPR/Cas9 knockout of BoVML1 in the WT produced a phenotype similar to that of 1180mu, whereas BoVML1 complementation restored normal leaf color, chloroplast ultrastructure, and plant morphology in 1180mu plants. Subcellular localization assays revealed that BoVML1 is targeted to chloroplasts. Transcriptomic profiling uncovered extensive gene downregulation in 1180mu and enrichment of differentially expressed genes (DEGs) in secondary metabolic, phenylpropanoid, and hormone signaling pathways, indicating broad transcriptional reprogramming associated with the virescent phenotype. Moreover, yeast two-hybrid (Y2H) and coimmunoprecipitation assays (Co-IP) demonstrated that BoVML1 interacts with BoPMD1 and BoNAC62, both of which are associated with stress responses. Together, these findings identify BoVML1 as a key positive regulator of chloroplast development, leaf color and leaf morphology in cabbage and provide a mechanistic framework and a practical genetic target for improving leaf color and plant morphogenesis in Brassica breeding programs.

Heat stress causes detrimental changes in the plant system, resulting in decreased photosynthesis, growth and crop productivity. In this study, we demonstrated that the combined application of hydrogen sulfide (H₂S) and sulfur (S) under heat stress conditions improved photosynthetic functions and the overall plant performance in rice (Oryza sativa L.). The treatment facilitated lipid remodelling, thereby strengthening membrane integrity and function. Plants treated with H₂S and S exhibited elevated levels of saturated acids, namely palmitic acid, steric acid, myristic acid, tridecanoic acid and butyric acid, alongside increased concentration of phytol and other phytosterols. This shift towards saturated lipids contributed to maintaining membrane fluidity and structural integrity under heat stress. Phytosterols like sitosterol and stigmasterol helped enhance plant resistance against heat stress. Similarly, the combined application of H₂S and S robusted the antioxidant defense system. The quantitative and histochemical staining indicated higher activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) and reduced hydrogen peroxide (H₂O₂) and thiobarbituric acid reactive substances (TBARS) content in the combined treatment under heat stress. Moreover, the microscopic examination revealed that the treatment also preserved the structural integrity of chloroplast and thylakoid membranes. Thereby, preserving the photosynthetic efficiency under heat stress. Thus, the synergistic application of H₂S and S regulated lipid remodelling, improved antioxidant defence and chloroplast structure, and collectively augmented tolerance in rice plants against heat stress. The study suggests the improved influence of H₂S in thermotolerance in the presence of S through remodelling lipids and the antioxidant system in rice.

Research on passion fruit traits primarily focuses on abiotic stress due to its detrimental impact on the industry. Transcription factors (TFs) mitigate abiotic stress by participating in various biological processes, among which heat shock factors (HSFs) play a pivotal role in responding to both biotic and abiotic stresses and conferring stress tolerance. This study identified 15 PeHSF family members with complete sequences using a high-quality genome of passion fruit. A systematic analysis of PeHSFs across the genome was conducted through bioinformatics and transcriptome sequencing. Transcriptomic data revealed higher expression levels of most PeHSFs in fruit pulp at stages T1 and T2 compared with T3, demonstrating the family's responsiveness to diverse abiotic stresses. Subsequent subcellular localization confirmed nuclear localization of the selected gene PeHSF-2. Heterologous expression of PeHSF-2 in the INVSc1 yeast strain and Arabidopsis thaliana significantly enhanced tolerance to drought, salt, cold, and heat stresses. Furthermore, PeHSF-2 over-expression up-regulated stress-responsive genes (P5CS1, SOS1, HSP70, and CBF2), and interacted with PeSIP2-2. This study lays the groundwork for further investigation into the regulatory mechanisms of PeHSFs under abiotic stress conditions.