The Plant Journal最新文献

The vernalization-mediated suppression of FLOWERING LOCUS C (FLC), a central flowering repressor, requires the coordinated action of non-coding RNA (COOLAIR/COLDAIR) and polycomb repressive complex 2 (PRC2)-mediated epigenetic silencing. However, the mechanistic integration of non-coding RNA transcription and PRC2 function during cold exposure remains poorly understood. In this study, we identify the R2R3-MYB transcription factor CDC5 as a critical regulator of vernalization-responsive flowering. Although the cdc5-2 mutant exhibits early flowering under normal conditions, it demonstrates delayed flowering after vernalization, along with defects in the low-temperature repression of FLC, non-coding RNA transcription, and H3K27me3 deposition. This study found that vernalization affects the binding of CDC5 to the FLC chromatin, thereby influencing the enrichment of RNA polymerase II on the FLC chromatin as well as the transcription of COOLAIR and COLDAIR. Furthermore, CDC5 physically interacts with PRC2 components, functioning as an important cofactor for H3K27me3 establishment at FLC. Our findings establish a regulatory paradigm where CDC5 coordinates non-coding RNA transcription with PRC2-mediated epigenetic silencing, thereby bridging transcriptional and epigenetic control of FLC during winter-induced flowering regulation.

Dehydration response element binding (DREB) transcription factors play a pivotal role in plant abiotic stress responses, but its evolutionary and functional characterization in buckwheat remains unexplored. Here, we conducted a comprehensive analysis of the DREB gene family across three buckwheat species, revealing segmental duplication as the primary driver of family expansion and potential purifying selection during evolution. A FtDREB02 gene, classified as group A2, was identified through genome-wide association analysis (GWAS) on drought tolerance and delphinidin content. Functional validation in Arabidopsis thaliana and the hairy root of Tartary buckwheat (Fagopyrum tataricum) demonstrated that overexpression of this gene promotes delphinidin biosynthesis and enhances plant resistance to water scarcity. Through the integration of DAP-seq and PEG transcriptome cluster analysis, a FtANS candidate was screened. Functional studies showed that FtDREB02 regulates delphinidin content by binding directly to DRE elements of the FtANS promoter. This research identifies and comprehensively analyzes the DREB family within buckwheat species, elucidating the regulatory mechanisms of FtDREB02 in controlling flavonoid biosynthesis and drought resistance, providing potential genetic resources for breeding buckwheat varieties with excellent agronomic traits.

Climate change and population growth threaten global freshwater resources and food security. Crassulacean acid metabolism (CAM) is a specialized photosynthetic adaptation that exhibits superior water use efficiency (WUE) compared to C₃ and C₄ photosynthesis. Mesembryanthemum crystallinum (common ice plant) is capable of shifting from C₃ to CAM, making it a key model for investigating photosynthesis plasticity and its potential to enhance crop stress resilience. To date, the molecular mechanisms underlying this high-WUE photosynthetic transition remain largely unknown. Using mass spectrometry-based proteomics and phosphoproteomics, we quantified 4233 phosphopeptides containing 4758 phosphorylation sites, including the well-characterized Serine 11 of phosphoenolpyruvate carboxylase 1 (PEPC1). It is a critical phosphorylation site facilitating nocturnal CO₂ fixation during CAM. Our analysis revealed many phosphorylation sites that exhibited similar diel patterns as the PEPC1 pS11, and they may be part of the regulatory network involved in CAM induction. Glycolysis/gluconeogenesis and carbon storage/breakdown modules exhibited extensive phosphorylation regulation, and vesicle trafficking could play a role in nocturnal carbon fixation. Furthermore, glycine-rich RNA-binding protein 7 (GRP7) in association with cold shock protein 1 (CSP1) emerged as a potential transcriptional switch for nocturnal stomatal opening. On the other hand, ABI5-binding protein 1 (AFP1) and oxidative stress 3 (OXS3)-activated ABA signaling, along with high CO₂ signaling and suppressed blue light signaling, may contribute to diurnal stomatal closure. These findings shed light on the protein phosphorylation changes and provide valuable targets for functional characterization of their roles in CAM induction.

The mitogen-activated protein kinase (MAPK) signaling cascades play crucial roles in mediating abiotic stress responses. This study characterized TaMPKKK18-3B, a member of the MAPK kinase kinase family, in mediating low-P stress response in Triticum aestivum. TaMPKKK18-3B contains conserved motifs shared by MAPKKK that target the nucleus. TaMPKKK18-3B transcripts were significantly upregulated under low-P stress conditions, an upregulation that was associated with the cis-acting element referred to as phosphate induction binding site (PIBS) situated in its promoter. Y-2H, BiFC and Co-IP assays indicated the interactions between TaMPKKK18-3B and the MAPKK member TaMPKK1.2-6B, which interacted with the MAPK member TaMPK2-1D. In turn, TaMPK2-1D interacted with the NAC transcription factor TaNAC2-5B via distinct conserved domains. These results suggested the formation of a MAPK regulatory module TaMPKKK18-3B/TaMPKK1.2-6B/TaMPK2-1D/TaNAC2-5B. Transgenic analysis on TaMPKKK18-3B module genes indicated their positive roles in modulating low-P adaptation by regulating phosphate (Pi) acquisition, acid phosphatase (AP) activity, and root system architecture (RSA) establishment. Dual luciferase, Y-1H, and EMSA assays suggested that TaNAC2-5B binds to the promoters of phosphate transporter gene TaPT2, AP gene TaAP1, and RSA-associated gene TaPIN3 and activates their transcription. Moreover, transgenic analyses validated the functions of stress-responsive genes in regulating Pi uptake, AP activity, and RSA behavior under deficient-P conditions. Strong positive correlations were observed between the transcript levels of TaMPKKK18-3B module genes and wheat yield under P-depleted field environments, with haplotype TaMPKKK18-3B-Hap 1 conferring wheat cultivars improved low-P stress tolerance. This study offers valuable insights into plant low-P response underlying the MAPK signaling pathway and provides markers for breeding the high-P-use-efficient cultivars in T. aestivum.

The female reproductive organ is essential for crop yield, but the mechanism underlying its development remains unclear in Brassica napus. Here, we identified four BnaCMA (Carpel Morphogenesis Abnormality) homologs, which play key roles in regulating gynoecium and silique development in B. napus. The BnaCMA triple mutants exhibited severe and penetrant abnormalities in the female reproductive organ, characterized by bifurcated styles, shortened siliques, and a total absence of seeds. These mutants exhibited a diminished transmitting tract and obstructed pollen tube elongation. The BnaCMA single mutants showed only less severe impairments in silique elongation. Genetic and molecular analyses demonstrated that BnaCMA directly interacts with BnaC09T0533300WE to control gynoecium and silique development. Furthermore, transcriptome analysis revealed that BnaCMA and BnaC09T0533300WE modulate the expression of multiple auxin response genes. Exogenous auxin treatment rescued the pistil length in mutants, indicating that BnaCMA and BnaC09T0533300WE regulate the sensitivity to auxin during gynoecium development. Altogether, our results elucidate a novel regulatory pathway in which BnaCMA interacts with BnaC09T0533300WE, orchestrating pistil and silique development through the auxin signaling pathway. These findings provide prospective genetic resources for molecular breeding aimed at enhancing yield and fertility in B. napus.

Cold stress is a major abiotic stress factor that affects plant growth and development, leading to yield loss. Abscisic acid (ABA) plays important roles in mediating abiotic stress tolerance. The molecular mechanisms underlying crosstalk between cold tolerance and ABA signaling remain elusive. Here, we report the E3 ubiquitin ligase OsPUB9 as a critical regulator linking ABA signaling and cold stress response in rice. We demonstrate that OsPUB9 negatively regulates cold tolerance. Cold induces OsPUB9 expression, which promotes the degradation of OsICE1, a key transcription factor in cold signaling, thereby suppressing the expression of OsCBFs. Intriguingly, OsCBF3 binds the OsPUB9 promoter, establishing a feedback loop that upregulates OsPUB9 under cold stress to fine-tune OsICE1 stability. ABA induces OsPUB9 degradation whereas OsPUB9 modulates ABA signaling by ubiquitinating and degrading the phosphatase OsABI2 and the kinase SAPK10, which form a regulatory complex. OsPUB9 disrupts OsABI2-mediated dephosphorylation of SAPK10, enhancing SAPK10 activity. SAPK10 phosphorylates OsICE1, further linking ABA and cold pathways. Our results elucidate a dual role for OsPUB9 in balancing ABA signaling and cold response through posttranslational regulation of OsABI2, SAPK10, and OsICE1, offering novel targets for breeding climate-resilient rice varieties.

The NAC transcription factors (TFs) are among the largest TF families in plants and play essential roles in growth, development, and stress responses. However, few studies have investigated how NAC TFs regulate salt gland development of recretohalophytes. In this study, we identified LbNAC55, a TF whose expression is upregulated by salt, from Limonium bicolor (a typical recretohalophyte which serves as a model for studying development and salt secretion of plant salt glands). Overexpression of LbNAC55 in L. bicolor significantly increases salt gland density and the salt tolerance of the species, whereas silencing LbNAC55 results in reduced salt gland development and diminished salt tolerance. Furthermore, yeast two-hybrid screening revealed that LbFLZ13 interacts with LbNAC55. Silencing LbFLZ13 similarly decreased salt gland formation and salt tolerance. Further studies showed that the reduction in salt gland density induced by the simultaneous silencing of both LbNAC55 and LbFLZ13 was significantly lower than that caused by the silencing of either gene alone. These results demonstrate that the regulatory modules of LbNAC55-LbFLZ13 control the expression of genes involved in salt gland development and secretion. These findings provide a new perspective on salt gland development in halophytes.

Leaves are the primary source of photosynthesis in plants. Elucidating the mechanism of leaf shape variation is essential for plant development. In previous studies, we demonstrated that BoALG10, a member of the glycosyltransferase family, is responsible for the smooth-leaved trait in kale (Brassica oleracea var. acephala), but the underlying molecular mechanism remains unclear. Here, we performed quantitative N-glycoproteomics with the BoALG10 overexpression line and the corresponding wild type. A cupredoxin domain-containing protein Skewed5 (SKU5) specifically underwent N-glycosylation in the BoALG10 overexpression line. Site-directed mutagenesis of the N-glycosylation site Asn-444 affected BoSKU5 nuclear localization and protein function in maintaining smooth leaf margins. Transcriptome sequencing showed that the BoSKU5 mutation altered the expression of auxin signaling and cell wall modification-related genes. We then identified a transcription factor BoARF8, which interacted with the protein BoSKU5, through yeast two-hybrid library screening. BoARF8 promoted smooth leaf margin formation and positively regulated its target gene BoUIF1. The BoSKU5-BoARF8 complex further enhanced the activation of the BoARF8-BoUIF1 cascade. Moreover, BoUIF1 directly repressed the expression of BoCUC2, a leaf margin regulator. The BoSKU5/BoARF8-BoUIF1-BoCUC2 module illustrated the novel function of Skewed5 in leaf margin development. This will provide deeper insights into the genetic improvement in plants.