The Plant Journal最新文献

Plant viruses, constrained by their limited genomic coding capacity, rely significantly on host factors for successful infection. Disruption of these essential host factors can confer resistance to viruses, with such factors categorized as susceptibility genes or recessive resistance genes. Recent research has identified developmentally regulated plasma membrane polypeptide (DREPP) proteins as susceptibility factors integral to the cell-to-cell movement of potyviruses. In the present study, we demonstrated that the silencing of StPCaP1, a DREPP gene in potato, confers novel resistance to both Potato virus Y (PVY, Potyvirus) and Potato virus S (PVS, Carlavirus). Interaction and subcellular localization analyses revealed that the movement proteins (MPs) of PVY (P3NPIPO) and PVS (TGB1) interact with StPCaP1, recruiting it to plasmodesmata (PD). Furthermore, transcriptome analysis and experimental validation indicated that compared to wild-type (WT) controls, StPCaP1-silenced lines exhibit significantly increased glucose content and elevated expression levels of several UDP-glucosyltransferases (UGTs), which are potential components of the callose synthesis complex. These findings suggest that StPCaP1 participates in callose deposition, as evidenced by the increased callose deposition at PD and reduced PD permeability observed in StPCaP1-silenced lines. Additionally, we found that StPCaP1 expression in Nicotiana benthamiana led to reduced callose deposition at PD and promoted PVY-GFP cell-to-cell movement in NbPCaP1-silenced plants in a concentration-dependent manner, which suggests the changes in callose deposition at PD induced by StPCaP1 relates to viral cell-to-cell movement. This study provides a deeper understanding of DREPP-mediated viral movement and highlights potential targets for developing virus-resistant crops.

Anthocyanins, the important antioxidants and signaling molecules, are natural polyphenolic compounds widely present in plants and essential for plant defense. However, little is known about the mechanisms underlying plant anthocyanin accumulation in relation to drought stress. This study reveals that drought stress induces significant anthocyanin accumulation in Rosa chinensis, alongside an increase in the expression of the MYB transcription factor (TF) gene RcMYB75 and the glutathione S-transferase (GST) gene RcGSTFL11. When overexpressed, RcMYB75 markedly increases anthocyanin contents in both roses and tobaccos; conversely, reducing its expression significantly lowers anthocyanin contents in rose petals. RcGSTFL11 was confirmed as an anthocyanin transporter and overexpression of RcGSTFL11 can restore the anthocyanin-deficient phenotype in the Arabidopsis tt19 mutant. Transgenic roses overexpressing RcGSTFL11 exhibit enhanced anthocyanin accumulation, while those with downregulated RcGSTFL11 have reduced contents. Transcriptomic analysis indicates that RcMYB75 upregulates the expression of key genes in the anthocyanin biosynthetic pathway and the anthocyanin transport gene RcGSTFL11. Ultimately, we also found that anthocyanin accumulation in these transgenics further enhances plant resistance to drought stress. Taken together, RcMYB75 and RcGSTFL11 promote the synthesis and transport of anthocyanins and play a key role in the feedforward loop responding to drought stress in roses. This study provides insights into the molecular mechanisms by which MYB TFs contribute to anthocyanin biosynthesis and transport, as well as the adaptive strategies of roses in response to drought stress.

Rhododendron species have the potential to be rich in secondary metabolites with pharmaceutical or industrial value. However, there is a lack of comprehensive metabolome studies at the genome level, particularly for unique and rare species like Rhododendron bailiense, which exclusively grows in karst environments in Guizhou, southwest China. Recently, genome assembly data for this species was available. In this study, nontargeted metabolomics was employed to investigate the secondary metabolites profile of R. bailiense callus. The callus of R. bailiense was induced using 0.2 mg L⁻¹ TDZ (Thidiazuron) + 0.1 mg L⁻¹ IBA (3-Indole butyric acid). A comparison between light-treated calli and dark-cultured calli revealed differential accumulation of metabolites, particularly in flavonoids, terpenoids, coumarins, and hydroxycinnamic acids, known for their beneficial effects such as antioxidant, anticancer, and anti-inflammatory properties. Proanthocyanidins, with various health-promoting effects, were found to accumulate significantly in dark-cultured calli. Light conditions promoted diterpene and triterpene products, whereas darkness favored sesquiterpene products. Additionally, the study demonstrated the potential of utilizing Agrobacterium transformation technology on callus suspension cells to enhance secondary metabolite production. Comparison with the genome of Rhododendron molle revealed that the R. bailiense genome exhibited active ‘glycosyltransferase activity,’ possessed a higher number of copies of monoterpene and sesquiterpene terpene synthases, and contained high copies of specific cytochrome P450 members (CYP71, CYP76, CYP79, CYP82, CYP736). This study offers valuable insights and potential strategies for the biosynthesis and production of Rhododendron secondary metabolites with pharmaceutical or industrial significance.

The movement of substances across biological membranes is often constrained by physical or energetic barriers, requiring the action of transporter proteins embedded within the lipidic bilayer. These transporters also provide finely tuned regulation of substrate fluxes, essential for maintaining cellular function under both normal and stress conditions. Consequently, transporters are subject to multiple levels of tight regulation, including posttranslational modifications (PTMs). Here, we review the current knowledge on PTMs affecting plant membrane transporters and their impact on protein function. The attachment of chemical groups to protein residues enables rapid modulation of transporter functions, influencing a wide range of protein characteristics. Phosphorylation stands out as the most common PTM, affecting transporter attributes such as activation status, localization and substrate specificity. In turn, ubiquitination acts as a signal for downregulation, either by targeting the transporters for proteasomal degradation or by triggering their endocytosis and subsequent vacuolar sorting. The roles of other, less common PTMs remain unclear, as limited examples exist and recent advances have been sparse. The complex dynamics of substrate transport, which require precise flux magnitudes and directions, appear to demand multi-layered control of the associated transporters. In consequence, further research is needed to investigate individual PTMs affecting transporters, as well as the interplay of multiple PTMs on a single transporter, to better understand how gradual modulation of protein function is achieved.

LHC assembly is a fundamental process in forming a peripheral antenna system, which has a significant impact on photosynthesis. However, the molecular mechanism of the LHC assembly still needs to be further investigated in monocotyledonous plants. Here, we identified a bifunctional protein YGL9 in rice, a homolog of cpSRP43 in Arabidopsis, mediates LHC assembly by simultaneously regulating LHCPs transport and chlorophyll synthesis. Mutation of YGL9 exhibits a yellow-green leaf phenotype, with reduced LHCPs contents, impaired photosystem activity and reduced chlorophyll content. YGL9 interacts with cpSRP54 forming the cpSRP complex that transport LHCPs, and YGL9 also interacts with and stabilizes OsGUN4, which is an activator of MgCh and participates in the regulation of chlorophyll synthesis, to synergistically participate in chlorophyll synthesis. Further, genetic evidence demonstrates that YGL9 functions in the same pathway as cpSRP54 and OsGUN4 to regulate LHCPs transport and chlorophyll synthesis. Thus, our study reveals a cross-relationship between LHCPs transport and chlorophyll synthesis, and provides new insights into the LHC assembly process in monocotyledonous plants.

Phloridzin has various functions, including antioxidant properties and the treatment of diabetes, and has long been used in pharmaceutical and physiological research. The glycosylation of phloretin is a key step in the biosynthesis of phloridzin. In this study, a genome-wide association study (GWAS) based on phloridzin content was applied, and the key gene GhUGT88F3 for phloridzin-specific biosynthesis was identified in cotton. A single-base deletion in GhUGT88F3 in haplotype I caused a frameshift mutation, leading to premature translation termination and a significant reduction in phloridzin content. Molecular docking revealed important amino acid residues for GhUGT88F3's UDP-glucose transfer activity. Additionally, the transcription factor GhMYB330 was found to positively regulate GhUGT88F3 expression through population transcriptome analysis and LUC experiment. Moreover, phloridzin content was significantly elevated in both GhUGT88F3 and GhMYB330 overexpression transgenic plants. This study expands the diversity of UDP-glucosyltransferases in plants and offers a potential strategy for the sustainable production of bioactive compounds with therapeutic potential.

Global metabolic and transcriptional reprogramming is a common event in plant abiotic stress responses, however, the relevant molecular mechanisms remain largely unknown. Here, we characterized the physiological function and molecular mechanism for the rice UGT706F1. We found that UGT706F1 can be potently induced by high temperature. Its overexpression can markedly enhance the heat tolerance of rice through improving the capacity of scavenging reactive oxygen species, whereas its functional deletion results in heat sensitivity in rice. To investigate the regulatory mechanism of UGT706F1 in response to high temperature, we carried out extensive screening of the in vitro enzymatic activity of UGT706F1 and discovered that UGT706F1 exhibits broad-spectrum activity toward flavonoid compounds. Through targeted flavonoid metabolomics analysis, we further revealed that the overexpression of UGT706F1 elevated the content of diverse flavonoids and flavonoid glycosides in rice. Subsequently, via transcriptome analysis, we found that following heat treatment, the overexpression of UGT706F1 was capable of enhancing the transcriptional activity of those genes including the flavonoid synthases, heat shock factors, heat shock proteins, glutathione S-transferase, and various antioxidant enzymes. Furthermore, we identified an R2R3 MYB-type transcription factor MYB61 and demonstrated that MYB61 could directly bind the promoter of UGT706F1 and activate the transcription of UGT706F1. The overexpression of MYB61 also enhanced the heat tolerance and increased flavonoid glycosides. Overall, this study unveiled a novel pathway of the plant heat tolerance response mediated by MYB61-UGT706F1 module and identified a new UGT player for the metabolic and transcriptional regulation under high-temperature circumstance.