Journal of Integrative Plant Biology最新文献

Leaf senescence can be triggered by various abiotic stresses. Among these, heat stress emerges as a pivotal environmental factor, particularly in light of the predicted rise in global temperatures. However, the molecular mechanism underlying heat-induced leaf senescence remains largely unexplored. As a cool-season grass species, tall fescue (Festuca arundinacea) is an ideal and imperative material for investigating heat-induced leaf senescence because heat stress easily triggers leaf senescence to influence its forage yield and turf quality. Here, we investigated the role of FaNAC047 in heat-induced leaf senescence. Overexpression of FaNAC047 promoted heat-induced leaf senescence in transgenic tall fescue that was evidenced by a more seriously destructive photosystem and higher accumulation of reactive oxygen species (ROS), whereas knockdown of FaNAC047 delayed leaf senescence. Further protein-DNA interaction assays indicated that FaNAC047 directly activated the transcriptions of NON-YELLOW COLORING 1 (FaNYC1), NYC1-like (FaNOL), and STAY-GREEN (FaSGR) but directly inhibited Catalases 2 (FaCAT2) expression, thereby promoting chlorophyll degradation and ROS accumulation. Subsequently, protein-protein interaction assays revealed that FaNAC047 physically interacted with FaNAC058 to enhance its regulatory effect on FaNYC1, FaNOL, FaSGR, and FaCAT2. Additionally, FaNAC047 could transcriptionally activate FaNAC058 expression to form a regulatory cascade, driving senescence progression. Consistently, the knockdown of FaNAC058 significantly delayed heat-induced leaf senescence. Collectively, our results reveal that FaNAC047-FaNAC058 module coordinately mediates chlorophyll degradation and ROS production to positively regulate heat-induced leaf senescence. The findings illustrate the molecular network of heat-induced leaf senescence for breeding heat-resistant plants.

This special issue features invited expert reviews that focus on the latest progress in the fields of plant growth and development, stress resistance, functional omics, and molecular breeding. The cover centers around a vibrant “Tree of Life”, its lush canopy adorned with key research species such as apples, soybeans, tomatoes, tobacco, Arabidopsis, wheat, corn, cotton, rice, and alfalfa. Surrounding the tree are depictions of plant viruses, hormones, and chemical elements, vividly highlighting current research hotspots. Together, they present a magnificent overview of the fl ourishing field of plant biological science.

Gram-negative bacteria are known to release extracellular vesicles (EVs) into their surrounding environment. However, the biological functions of the proteins contained within these vesicles remain largely unknown. Here, we used tandem mass tag (TMT) proteomic analysis to characterize protein cargoes within EVs of the phytopathogen Pseudomonas syringae pv. tomato DC3000 (Pto DC3000). Our investigation revealed that one catalase, KatB, is enriched in bacterial EVs. This enzyme confers EVs with the capacity to detoxify both exogenous and plant-produced H₂O₂, thereby contributing to the pathogen's proliferation within the plants. Interestingly, reactive oxygen species (ROS) stress stimulates bacterial EV secretion and enhances the package of KatB into these vesicles. This regulatory process depends on a periplasmic ankyrin-like protein, AnkB. Both AnkB and KatB are encoded within a small operon, and their mutant strains exhibit impaired growth in plant hosts. Furthermore, the treatment of EVs pelleted from bacterial culture supernatants activates the immune responses of plants, and the absence of KatB in EVs further enhances this protective activity. Collectively, our findings indicate that bacteria secreted KatB via EVs to interact with and reduce the host's oxidative environment, thereby promoting their proliferation within plants.

Knocking out three susceptibility genes (Pi21, Bsr-d1, and Xa5) in a rice breeding line that contains the resistance Piz-t produced enhanced broad-spectrum resistance against the fungal pathogen Magnaporthe oryzae and the bacterial pathogen Xanthomonas oryzae pv. oryzae without obvious growth penalty.

Late blight, caused by the oomycete plant pathogen Phytophthora infestans, is a destructive disease that leads to significant yield loss in potatoes and tomatoes. The introgression of disease resistance (R) genes, which encode nucleotide-binding domain leucine-rich repeat-containing receptors (NLRs), into cultivated potatoes, is highly effective in controlling late blight. Here, we generated transgenic 2R and 3R potato lines by stacking R genes Rpi-blb2/Rpi-vnt1.1 and Rpi-vnt1.1/RB/R8, respectively, in the susceptible cv. Desiree background. The resulting 2R and 3R transgenic potato plants showed resistance to highly virulent P. infestans field isolates. We hypothesized that stacking R genes either resulted in up-regulation of a broader range of immune-related genes, or, more importantly, increase in the fold change of gene expression. To test our hypotheses, we performed transcriptome analysis and identified a subset of core immune-related genes that are induced in response to P. infestans in transgenic lines carrying single R genes versus lines carrying stacks of multiple R genes. In our analysis, stacking R genes resulted not only in the induction of a broader range of defense-associated genes but also a global increase in gene expression fold change, caused by the pathogen. We further demonstrated that the calcium-dependent protein kinase 16 (StCDPK16) gene significantly contributed to resistance to a virulent P. infestans strain, in the R gene background, in a kinase activity-dependent manner. Thus, our data suggest that stacking the R genes enhances late blight resistance through modulating the expression of a broader range of defense-related genes and highlights CDPK16 as a novel player in potato R gene-mediated resistance.

Rice bacterial blight, caused by the pathogen Xanthomonas oryzae pv. oryzae (Xoo), poses a significant threat to rice crops. Arginine methylation, a post-translational modification of proteins, plays a pivotal role in transcriptional regulation, RNA processing, and the biosynthesis of plant hormones. Previous research has established that protein arginine methyltransferases (PRMTs) significantly influence protein function through arginine methylation. Nonetheless, the specific role of PRMT5 in regulating salicylic acid (SA) biosynthesis and plant immunity has been relatively unexplored. In this study, we elucidate the role of a rice protein arginine methyltransferase, OsPRMT5, in enhancing rice resistance to Xoo infection by interacting with the SA biosynthesis enzyme phenylalanine ammonia lyase 1 in rice (OsPAL1). Our results indicate that OsPRMT5 methylates OsPAL1 at the arginine residue 75, which affects the interaction between OsPRMT5 and OsPAL1 and subsequently boosts phenylalanine ammonia lyase (PAL) enzyme activity, leading to heightened SA accumulation. Conversely, compared to OsPAL1 overexpression plants in wild-type TP309 background, OsPAL1 overexpression plants in osprmt5 knockout (KO) mutants background exhibited diminished PAL activity. Furthermore, osprmt5 ospal1 double mutants demonstrated reduced resistance to bacterial blight compared to the OsPAL1-KO group. Additionally, we discovered that the Xoo effector protein PXO_01039 undermines the interaction between OsPRMT5 and OsPAL1, thereby facilitating Xoo infection. PXO_01039 binds to OsPRMT5, preventing the formation of the OsPRMT5-OsPAL1 complex, which results in decreased PAL activity and lower SA accumulation. In conclusion, our findings unveil how OsPRMT5 modulates the methylation and enzymatic activity of OsPAL1, a crucial enzyme in SA biosynthesis, to bolster plant antibacterial defenses.

Diverse heterotic groups have been developed in China over several decades, but their genomic divergences have not been systematically studied after improvement. In this study, we performed Maize6H-60K array of 5,822 maize accessions and whole-genome re-sequencing of 150 inbred lines collected in China. Using multiple population structure analysis methods, we established a genetic boundary used to categorize heterotic groups and germplasm resources. We identified three chloroplast-cytoplasmic types that evolved during adaptation to diverse climatic environments in maize through phylogenetic and haplotype analyses. Comparative analyses revealed obvious genetic differences between heterotic groups and germplasm resources at both the chloroplast and nuclear genome levels, especially in the unique heterotic groups HG1 and HG2, which exhibited distinct regionality and genetic uniqueness. The divergent differentiation of heterotic groups from germplasm resources was driven by differential selection in specific genomic regions. Genome-wide selective sweep analysis identified core selected regions and candidate selected genes associated with traits between heterotic groups, highlighting that stress response- and plant defense-related genes were selected for environmental adaptation across a broad latitudinal range in China. Meanwhile, a genome-wide association study analysis provided evidence that core selected genes served as an important candidate gene pool with a potential role in genetic improvement. Gene exchanges among heterotic groups, which avoided the predominant heterotic patterns as much as possible, occurred to achieve population improvement during modern maize breeding. This study provides insights into the population differentiation and genetic characteristics of heterotic groups, which will facilitate the utilization of germplasm resources, the creation of novel maize germplasm, and the optimization of heterotic patterns during future maize breeding in China.

In plants, the photoperiod sensitivity directly influences flowering time, which in turn affects latitudinal adaptation and yield. However, research into the mechanisms underlying photoperiod sensitivity, particularly those mediated by epigenetic regulation, is still in its nascent stages. In this study, we analyzed the regulation of photoperiod sensitivity in Arabidopsis thaliana. We demonstrate that the evening complex LUX ARRYTHMO (LUX) and the chromatin remodeling factor SWITCH/SUCROSE NONFERMENTING 3C (SWI3C) regulate GI locus chromatin compaction and H3K4me3 modification levels at the GIGANTEA locus under different photoperiod conditions. This mechanism is one of the key factors that allow plants to distinguish between long-day and short-day photoperiods. Our study provides insight into how the LUX-SWI3C module regulates photoperiod sensitivity at the epigenetic level.