Plant Physiology and Biochemistry最新文献

Following harvest, the medicinal quality of Dendrobium officinale declines due to ongoing metabolism. This study applied sodium nitroprusside (SNP) treatment and used biochemical and transcriptomic analyses to investigate its effects. Results showed that 400 μmol L^-1 SNP increased soluble sugars, proteins, antioxidant capacity, and stress resistance. Transcriptomic analysis revealed upregulation of MAN, PFK, PFP, and GMD, correlating with a 163% increase in polysaccharides, while downregulation of ALDO, TREH, and ENPP reduced cellulose and starch. Upregulation of F3H, CHS, and HCT boosted flavonoids and polyphenols, and upregulation of MVK, PAL, COMT, 4CL, and CYP73A led to a 179% rise in dendrobine. Transcription factors ERF, MYB, and WRKY were also implicated. SNP treatment redirected carbon allocation from starch/cellulose to bioactive polysaccharides and promoted dendrobine and flavonoid accumulation, thereby enhancing medicinal quality. This study offers new strategies for maintaining postharvest quality in medicinal plants.

Schizonepeta tenuifolia is a medicinal plant whose bioactive monoterpenoids, such as pulegone, are biosynthesized and stored in peltate glandular trichomes. Although jasmonate signaling is known to promote trichome development and terpenoid accumulation, the underlying transcriptional regulators in S. tenuifolia remain unknown. Here, we identified two jasmonate-responsive MYC2-type transcription factors, StMYC2a and StMYC2b, which are predominantly expressed in leaves and localized to the nucleus. Overexpression of StMYC2a and StMYC2b in S. tenuifolia increased the peltate glandular trichome density and monoterpenoid content. Conversely, transgenically silenced StMYC2a and StMYC2b lines had attenuated peltate glandular trichome development and reduced monoterpenoid accumulation. We further demonstrated that StMYC2a and StMYC2b directly activate two key monoterpenoid biosynthetic genes, StL3OH and StPR, by binding to G-box motifs in their promoters. Protein interaction analysis reveals that only StMYC2b physically interacts with the repressor StJAZ2, which suppresses StMYC2b-mediated transactivation, but this repression was alleviated upon stimulation with methyl jasmonate. The results revealed that the StJAZ2-StMYC2b-StL3OH/StPR functional module regulates jasmonic acid signaling-mediated glandular trichome development and monoterpenoid synthesis in S. tenuifolia. The enrichment of the transcriptional regulatory network for monoterpenoid synthesis provides a new theoretical basis for producing S. tenuifolia with high medicinal value.

The escalating threat of cadmium (Cd) contamination in agricultural soils poses serious challenges to food security and necessitates sustainable mitigation strategies. This study evaluated the combined effects of plant growth-promoting rhizobacteria (PGPR) and earthworms (Eisenia fetida) on Cd accumulation and associated physiological responses in rice (Oryza sativa L.). A controlled pot experiment was conducted under greenhouse conditions using plants exposed to Cd stress (100 mg kg^-1 soil), representing a severe contamination scenario used to evaluate mitigation responses under high Cd stress, with the application of Serratia marcescens, Pseudomonas fluorescens, and earthworms, individually and in combination. The results indicated that combined inoculation with PGPR and earthworms enhanced plant growth, improved photosynthetic efficiency, stimulated antioxidant defenses, increased osmolyte accumulation, and modulated cell wall-associated biochemical components, contributing to reduced Cd accumulation in O. sativa tissues. Furthermore, improvements in nutrient uptake and regulation of stress-related biochemical processes were observed, supporting enhanced tolerance under Cd exposure. Health risk indices (hazard quotient and hazard index) were markedly reduced, reflecting lower Cd transfer to edible tissues. Protein fraction and ribosomal protein analyses indicated increased total soluble protein content, enhanced protease activity, and greater ribosomal protein yield under biological treatments. Overall, the combined application of PGPR and earthworm reduced Cd accumulation and supported physiological resilience under controlled greenhouse conditions however, field validation and long-term assessment are required before broader agronomic application can be inferred.

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.

Low temperature is a key environmental stimulus that promotes anthocyanin biosynthesis in Begonia semperflorens. However, the molecular regulatory mechanism remains largely elusive. In this study, we first identified and functionally characterized dihydroflavonol 4-reductase (BsDFR) as a key enzyme in the anthocyanin pathway. Subsequently, we identified an R2R3-MYB transcription factor, BsMYB5, as a central regulator whose expression is rapidly upregulated under low-temperature treatment. Functional analyses revealed that BsMYB5 overexpression in B. semperflorens significantly enhances anthocyanin accumulation under both normal and low-temperature conditions. We further discovered that BsMYB5 specifically interacts with a low-temperature-induced bHLH transcription factor, BsEGL1. Crucially, we demonstrated that BsMYB5 and BsEGL1 form a functional complex that directly and synergistically binds to the promoter of BsDFR, as evidenced by yeast one-hybrid, dual-luciferase, and electrophoretic mobility shift assays, thereby activating its expression. Collectively, this study elucidates a core BsMYB5-BsEGL1 transcriptional module that mediates low-temperature-responsive anthocyanin biosynthesis in B. semperflorens, not only providing mechanistic insight into environmental adaptation but also promising genetic targets for breeding cultivars with enhanced cold tolerance and ornamental value.

Rice leaf angle, a major determinant of plant architecture and yield potential, is tightly regulated by brassinosteroid (BR) signaling. Although the core BR pathway is well characterized, how BR responses are precisely controlled in space and time remains unclear. Here, we identify OsvWA36, a novel regulator required to fine-tune BR signaling. The osvwa36 mutant exhibits typical BR-deficient phenotypes, including decreased leaf angle and reduced BR responsiveness, whereas ubiquitin promoter-driven expression of OsvWA36 confers BR hypersensitivity. We further show that the OsvWA36 protein undergoes intrinsically disordered region (IDR)-driven liquid-liquid phase separation to form dynamic condensates associated with the endoplasmic reticulum. These condensates facilitate a direct interaction between the OsvWA36 protein and the KNOX transcription factor OSH1. Genetic analyses indicate that OsvWA36 is necessary for full activation of the OSH1-regulated transcriptional program, including induction of BR catabolic genes (e.g., CYP734A2/4/6). In parallel, OsvWA36 broadly influences the expression of key activators of BR signaling and biosynthesis. Collectively, OsvWA36 integrates both positive and negative regulatory branches of the BR network to optimize leaf angle. These findings reveal a phase separation-based mechanism underlying hormone signaling and suggest that OsvWA36 is a promising target for the engineering of plant architecture.

Albino mutant tea tree is a germplasm resource with distinctive characteristics, having high amino acids and low tea polyphenol content, as well as significant ornamental value. Grasping the molecular underpinnings of 'Huangjinya' leucism is crucial for enhancing its quality consistency and boosting its production. Among the progeny of 'Huangjinya,' green and albino mutant plants were previously discovered. To pinpoint the genetic factors linked to the whitening trait in 'Huangjinya', whole-genome resequencing was conducted on two phenotypic groups: extreme albino mutant plants and extreme green mutant plants. Based on genome variation and gene annotation, CsPPR1 and CsPPR2, pentatricopeptide repeat (PPR) protein family genes, were selected as candidate genes related to the albino phenotype. Cloning analysis confirmed that the protein sequences encoded by CsPPR1 and CsPPR2 in 'Huangjinya' and 'Fuding Dabaicha' have different amino acid residues. qRT-PCR validation showed that the relative expression levels of CsPPR1 and CsPPR2 in green mutant plants of the F1 progeny were higher than those in albino mutant plants, and their relative expression levels in 'Fuding Dabaicha' were higher than in 'Huangjinya'. VIGS-mediated silencing of these genes induced photobleaching in the plants. Moreover, transient overexpression of these genes in 'Huangjinya' leaves increased chlorophyll content. Therefore, it was concluded that CsPPR1 and CsPPR2 are genes potentially linked to the 'Huangjinya' leucistic trait, which can assist in further exploration of the albinism mechanism.

Pollen tube (PT) growth is crucial for double fertilization and seed production in angiosperms. Signaling peptides have emerged as major factors in cell-to-cell communication during reproduction. However, the characteristics and functions of these peptides and their receptors remain largely unknown, particularly in rice species. Here, we identified five Oryza sativa late anther tomato 52 (OsLAT52) genes in the rice genome, homologs of tomato LAT52, which are crucial for pollen-pistil interactions through receptor-mediated signaling in tomato. OsLAT52a was the most prominently expressed gene among the five OsLAT52s, and the GFP signal from OsLAT52 accumulated at the tip of the PT in pOsLAT52a:OsLAT52a-eGFP transgenic rice. oslat52a-1 knockout mutants showed normal vegetative growth and development of reproductive organs but exhibited partial male sterility. These mutants exhibited defects in pollen germination and PT elongation, accompanied by reduced reactive oxygen species (ROS) levels in the PTs. Co-immunoprecipitation (Co-IP) assays showed that OsLAT52a interacted with Male-gene transfer defective 2 (MTD2), which belongs to the Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) family. Transcript analysis revealed that genes downstream of OsLAT52a are involved in diverse signaling pathways, redox homeostasis, and cell wall remodeling. Collectively, our findings identify OsLAT52a as a pollen-specific peptide signal that engages CrRLK1L receptor and modulates the ROS balance to ensure proper PT growth in rice.