The Plant Journal最新文献

Rice tillering determines grain yield, yet the molecular regulatory network is still limited. In this study, we demonstrated that the transcription factor OsMADS60 promotes the expression of the auxin transporter OsPIN5b to affect auxin distribution and inhibit rice tillering and grain yield. Natural variation was observed in the promoter region of OsMADS60, with its expression level negatively correlated with tiller number and inducible by auxin. Overexpression of OsMADS60 resulted in reduced tillers and grain yield, whereas CRISPR-mediated knockouts of OsMADS60 led to increased tillering and yield. OsMADS60 was found to directly bind the CArG motif [CATTTAC] in the OsPIN5b promoter, thereby upregulating its expression. Moreover, we found that auxin content in various tissues of OsMADS60 and OsPIN5b overexpression lines increased relative to the wild-type ZH11, whereas the auxin levels in mutant lines showed the opposite trend. Genetic analysis further confirmed that OsPIN5b acted downstream of OsMADS60, coregulating the expression of genes involved in hormone pathways. Our findings reveal that OsMADS60 modulates auxin distribution by promoting OsPIN5b expression, thereby influencing rice tillering. This regulatory mechanism holds significant potential for the genetic improvement of rice architecture and grain yield.

Late blight, caused by Phytophthora infestans (P. infestans), seriously compromises tomato growth and yield. PAMP-induced peptides (PIPs) are secreted peptides that act as endogenous elicitors, triggering plant immune responses. Our previous research indicated that the exogenous application of PIP1 from Solanum pimpinelifolium L3708, named SpPIP1, enhances tomato resistance to P. infestans. However, little is known about the roles of additional family members in tomato resistance to P. infestans. In addition, there remains a significant gap in understanding the receptors of SpPIPs and the transcription factors (TFs) that regulate SpPIPs signaling in tomato defense, and the combination of SpPIPs signaling and TFs in defending against pathogens is rarely studied. This study demonstrates that the exogenous application of SpPIP-LIKE1 (SpPIPL1) also strengthens tomato resistance by affecting the phenylpropanoid biosynthesis pathway. Both SpPIP1 and SpPIPL1 trigger plant defense responses in a manner dependent on RLK7L. Tomato plants overexpressing the precursors of SpPIP1 and SpPIPL1 (SpprePIP1 and SpprePIPL1) exhibited enhanced expression of pathogenesis-related genes, elevated H₂O₂ and ABA levels, and increased lignin accumulation. Notably, SpWRKY65 was identified as a transcriptional activator of SpprePIP1 and SpprePIPL1. Disease resistance assays and gene expression analyses revealed that overexpression of SpWRKY65 (OEWRKY65) confers tomato resistance to P. infestans, while wrky65 knockout led to the opposite effect. Intriguingly, transgenic tomato studies showed that either spraying OEWRKY65 with SpPIPs or co-overexpressing SpprePIP1 and SpWRKY65 further augmented tomato resistance, underscoring the potential of gene stacking in enhancing disease resistance. In summary, this study offers new perspectives on controlling late blight and developing tomato varieties with improved resistance. The results emphasize the potential of exogenous SpPIPs application as an eco-friendly strategy for crop protection, laying a theoretical foundation for advancing crop breeding.

When pollen lands on a receptive stigma, it germinates and extends a tube inside the transmitting tissue of the pistil to deliver the sperm cells for double fertilization. The growth of the pollen tube triggers significant alterations in its gene expression. The extent to which these changes occur in the vegetative cell or extend to the sperm cells transported by the tube is unclear but important to determine since sperm cells are believed to acquire a competency for fertilization during pollen–pistil interactions. To address these questions, we compared the transcriptomes of Arabidopsis thaliana sperm cells and vegetative nuclei isolated from mature pollen grains with those isolated from in vitro-grown pollen tubes. Importantly, we also compared transcriptomes of sperm cells obtained from pollen tubes grown under semi-in vivo conditions where tubes passed through a pistil section. Our data show that extensive transcriptomic changes occur in sperm cells during pollen tube growth, some of which are elicited only as sperms are carried through the pistil. Their analysis reveals a host of previously unidentified transcripts that may facilitate sperm maturation and gamete fusion. The vegetative cell undergoes even more extensive transcriptomic reprogramming during pollen tube growth, mainly through the upregulation of genes associated with pollen tube growth and vesicle-mediated transport. Interestingly, ATAC-seq data show that the promoters of genes upregulated in sperm during pollen tube growth are already accessible in sperm chromatin of mature pollen grains, suggesting pre-configured promoter accessibility. This study's expression data can be further explored here: https://bar.utoronto.ca/eFP-Seq_Browser/.

The widely distributed heat shock protein DnaJ is renowned for its pivotal role in enhancing thermal tolerance in plants; however, its involvement in drought tolerance remains elusive. In this study, genes encoding DnaJ1 were cloned from drought-resistant wild tomato (Solanum pennellii) and drought-sensitive cultivated tomato (Solanum lycopersicum). SpDnaJ1 and SlDnaJ1 from both tomato species were localized in the chloroplast, and their gene expression was induced by various abiotic stresses. SpDnaJ1 was found to be a more potent regulator than SlDnaJ1 in oxidative stress tolerance when expressed in yeast cells. Overexpression of SpDnaJ1 was demonstrated to confer drought tolerance in transgenic plants of cultivated tomato. These transgenic plants exhibited reduced relative conductivity, leaf water loss rate, and malondialdehyde content as compared to the wild-type plants following drought treatment. RNA-seq analysis revealed that overexpression of SpDnaJ1 primarily affects the expression of genes associated with antioxidants, protease inhibitors, and MAPK signaling in response to drought stress. Screening of a tomato cDNA library in the yeast two-hybrid system identified a flavanone 3-hydroxylase-like protein (F3HL) as an interacting protein of DnaJ1. Subsequent findings revealed that F3HL enhances drought tolerance in tomato by increasing the activity of antioxidant enzymes and scavenging reactive oxygen species. These findings demonstrate a pivotal role of DnaJ1–F3HL interaction in enhancing drought tolerance, unveiling a novel molecular mechanism in drought tolerance in plants.

Bryophytes, which include mosses, liverworts, and hornworts, have evolved a highly successful strategy for thriving in terrestrial environments, allowing them to occupy nearly every land ecosystem. Their success is due to a unique combination of biochemical adaptations, diverse structural forms, and specialized life cycle strategies. The key to their evolutionary success lies in their genomic diversity. To fully decode this diversity, the use of advanced genome engineering techniques is crucial. In this review, we explore the genomic diversity of bryophytes and the latest advancements in their genome studies and engineering, ranging from precise gene editing to whole-genome synthesis. Notably, the moss Physcomitrium patens stands out as the only land plant capable of efficiently utilizing homologous recombination for precise genome engineering. This capability has heralded a new era in plant synthetic genomics. By focusing on bryophytes, we emphasize the potential benefits of unraveling the genetic traits, which could have significant implications across various scientific fields, from fundamental biology to biotechnological applications.

Melatonin significantly influences the regulation of plant growth, development, and stress tolerance. However, the regulatory mechanisms underlying melatonin accumulation for drought tolerance in citrus are not fully understood. In this study, we first demonstrated that application of exogenous melatonin resulted in better drought tolerance by reducing water loss and maintaining redox homeostasis. Genome-wide analysis revealed presence of 96 genes involved in melatonin biosynthesis in trifoliate orange (Poncirus trifoliata L., also known as Citrus trifoliata L.). Seven caffeic acid-O-methyltransferases (COMT) genes were detected, among which PtCOMT5 was most substantially induced by drought stress and predominantly expressed in roots and leaves. Overexpression of PtCOMT5 led to enhanced drought tolerance in trifoliate orange by promoting melatonin accumulation and root development, whereas CRISPR-Cas9-mediated PtCOMT5 mutation led to opposite phenotype. Yeast one-hybrid screening and protein-DNA interaction assays confirmed that the transcription factor PtbHLH28 acts a transcriptional activator of PtCOMT5 through interacting with the gene promoter. In addition, PtbHLH28 was found to be positively regulated by PtABF4, a core member of the ABA signaling pathway. PtbHLH28 and PtABF4 were demonstrated to function in drought tolerance by regulating PtCOMT5-mediated melatonin synthesis and root development. Overall, this study elucidates the crucial role of a molecular module composed of PtABF4-PtbHLH28-PtCOMT5 in modulation of melatonin accumulation for promoting drought tolerance and root development in citrus. Our findings shed light on melatonin accumulation in plants exposed to drought stress and gain new insight into the regulatory network associated with the function of melatonin in plant development and stress response.