The Plant Journal最新文献

Soil heavy metal contamination poses a serious threat to the safety of crop production. To elucidate the physiological and molecular mechanisms by which drip irrigation reduces the upward translocation of heavy metals in soybeans, this study established a drip irrigation experiment with four irrigation frequencies. A systematic analysis was conducted on the differences in various physiological indicators and gene expression in soybean roots under combined contamination of Cd, Pb, and Cr(VI), in comparison with surface irrigation. Results indicate that: (i) drip irrigation maintained root physiological activity by enhancing antioxidant enzyme activities and osmotic adjustment capacity. (ii) Drip irrigation up-regulated the expression of genes encoding key enzymes involved in the synthesis of cytokinin and ethylene, as well as genes associated with transport functions such as metal ion transmembrane transporter activity, thereby promoting root growth and enhancing heavy metal uptake. (iii) Drip irrigation stimulated the synthesis of small organic molecules such as organic acids, amino acids, glutathione, and nicotinamide in soybean roots, consequently reinforcing the root's capacity for heavy metal retention. (iv) The reduced expression of genes encoding lignin biosynthesis-related enzymes under drip irrigation restricted xylem development, thus diminishing heavy metal translocation to aboveground parts. The findings provide a theoretical foundation for the safe utilization of heavy metal-contaminated farmland.

As an important tool for plant regeneration, somatic embryogenesis (SE) exemplifies the remarkable plasticity and totipotency of plant cells. Auxin is a well-known initiator that drives the reprogramming of somatic cells into a pluripotent or totipotent state during somatic embryo formation. Accordingly, the auxin analog 2,4-dichlorophenoxyacetic acid (2,4-D) is the most widely applied hormone in SE induction media. Auxin and ethylene interact in many developmental processes, and ethylene signaling has been known for decades to be rapidly activated by auxin. However, the role of ethylene in SE remains elusive. In this study, we demonstrate that a series of Arabidopsis mutants with either enhanced or compromised ethylene signaling exhibit correspondingly higher or lower seed-derived SE induction rates under continuous 2,4-D treatment, respectively. Ethylene precursors, including 1-aminocyclopropane-1-carboxylic acid (ACC) and ethephon (ETH), promoted SE induction, whereas the ethylene perception inhibitor 1-methylcyclopropene (1-MCP) suppressed it. These results indicate that ethylene response is essential for auxin-mediated SE. Molecular and histological analyses revealed that auxin rapidly activates the transcription of key ethylene biosynthesis genes, such as ACC SYNTHASE (ACS) and ACC OXIDASE 2 (ACO2), leading to enhanced ethylene responses during early SE. Furthermore, we found that the core ethylene transcription factors ETHYLENE-INSENSITIVE3 (EIN3) and EIN3-LIKE 1 (EIL1) directly bind to the promoters of the embryonic identity genes LEAFY COTYLEDON 1 (LEC1) and LEC2, and that ethylene signaling positively regulates LEC1 transcription. Taken together, our results demonstrate that ethylene signaling promotes auxin-mediated SE through direct upregulation of LEC1 expression.

The ERECTA family of leucine-rich repeat receptor kinases has emerged as central coordinators of plant developmental signaling: three members of the ERECTA family-ERECTA and its paralogs ERECTA-LIKE1 (ERL1) and ERL2-uniquely as well as synergistically integrate diverse internal and environmental cues to regulate growth, morphogenesis, and stress responses. From the initial genetic characterization of the classic Arabidopsis Landsberg erecta (Ler) accession to the subsequent identification of EPIDERMAL PATTERNING FACTOR (EPF/EPFL) peptides as cognate ligands, studies on the ERECTA family have transformed our understanding of peptide-receptor signaling in plants. In this review, we first describe the developmental processes regulated by the EPF/EPFL-ERECTA family ligand-receptor module, including shoot apical meristem homeostasis, inflorescence stem growth, leaf serration, reproductive development, stomatal development, and vascular patterning. We then synthesize the signaling logic of the ERECTA family, with specific focus on the autocrine versus juxtacrine and paracrine modes of signaling as well as the mechanisms ensuring signal specificity. We further discuss the mechanisms of ERECTA-family receptor signaling, from ligand perception, receptor activation and attenuation, signal transduction, to subcellular trafficking. Lastly, we highlight emerging non-canonical functions of ERECTA-family receptors beyond the plasma membrane. Our review provides comprehensive and updated knowledge of ERECTA-family receptor kinases as versatile regulators of plant development, and highlights mechanistic insights to be leveraged for improving plant growth and resilience.

Plants face constant environmental changes and must integrate external and internal cues to coordinate growth, development, reproduction, and stress responses. A major strategy is perception at the cell surface via a large, diverse network of receptors. Here, we outline how these receptors recognise extracellular signals and assemble active complexes with appropriate co-receptors. Diverse ectodomain structures enable the recognition of peptides and proteins, glycans, lipids, phytohormones, and other small molecules, as well as changes in cell wall status. We then summarise the downstream pathways, highlighting how cytosolic kinase domains couple to receptor-like cytoplasmic kinases, MAPK modules and other signalling components, and how timing, partner choice, and cellular context confer specificity to produce distinct physiological outputs across diverse processes. Finally, we discuss the origin and evolution of cell surface receptors. Receptor-like kinases share a single origin and significantly diversified around the emergence of land plants to support new functions. Together, this perception system repeatedly adapted to new roles and point to opportunities to reprogramme cell surface receptors for resilience and crop improvement.

Specialized metabolites are central to plant defense, signaling and ecological interactions, yet we still lack a macroevolutionary framework explaining how this diversity is structured across angiosperms. Here, we integrate the open LOTUS chemical repository with standardized taxonomy to map a curated 'chemical core' comprising 77 404 family-supported occurrences across 12 representative families spanning Magnoliids, Monocots, and Eudicots. Chemical composition shows strong higher-level structure, delineating major lineages while revealing a striking evolutionary topology: inter-lineage divergence is dominated by metabolite replacement rather than accumulation. Across family pairs, β-diversity is overwhelmingly explained by turnover, indicating that chemical disparity rarely arises from one lineage retaining subsets of another's repertoire. Despite this universal turnover regime, lineages occupy distinct physicochemical and elemental neighborhoods, consistent with divergent evolutionary strategies under shared allocation constraints. Magnoliids define a lipophilic boundary characterized by greater investment in nitrogen-bearing and aromatic-rich defenses; Monocots occupy a more hydrophilic, high-molecular-weight and structurally saturated niche; and Eudicots expand oxygen-rich carbon scaffolds with reduced nitrogen dependence. Together, our results indicate that angiosperm chemical evolution is highly dynamic at the compositional level, yet constrained at the architectural level, with persistent turnover generating lineage-specific chemical identities within inherited physicochemical corridors. This work provides a reproducible open data foundation for testing mechanistic links between biosynthetic organization, ecological antagonists, and evolutionary diversification of plant chemistry.

Heat stress is a major environmental factor that limits plant growth, yield, and quality, and can even cause plant death. Although the homeodomain-leucine zipper transcription factor family plays broad roles in regulating plant stress responses, their underlying mechanisms in apple heat stress remain unclear. Here, we show that MdHB7 positively regulates basal thermotolerance in apple by promoting reactive oxygen species (ROS) scavenging and lignin accumulation. Transcriptome sequencing and functional annotation identified two differentially expressed genes, MdPRX66 (Peroxidase) and MdLac17 (Laccase), as potential MdHB7 targets involved in heat tolerance. Transcriptional analyses revealed that MdHB7 directly binds to the promoters of MdPRX66 and MdLac17 to activate their expression. Functional assays and physiological measurements further indicated two regulatory mechanisms of MdHB7-mediated thermotolerance: MdHB7 enhances peroxidase (POD) activity by activating MdPRX66, thereby promoting ROS scavenging; and it increases laccase activity by activating MdLac17, thereby facilitating lignin accumulation. Together, these findings demonstrate that MdHB7 mediates apple heat stress responses by regulating ROS scavenging and lignin accumulation, providing new insights into the molecular mechanisms of plant thermotolerance.

Soil salinity severely constrains agricultural production. Elucidating the salt-tolerance mechanisms of halophytes can provide innovative approaches for improving the salt tolerance of crop plants. In this study, we performed genome-wide identification and analysis of 36 LbHDZ genes encoding homeodomain-leucine zipper (HD-ZIP) transcription factors in Limonium bicolor, a typical recretohalophyte that excretes excess salt ions through specialized salt glands. Expression profiling across different stages of salt gland development, as well as in various tissues under salt stress, indicated that multiple LbHDZ genes are involved in regulating salt gland development and salt tolerance. Among these genes, LbHDZ14 (a member of the HD-ZIP II subfamily) exhibited sustained high expression during the critical period of salt gland formation, while its transcript levels were significantly downregulated in leaves and roots under salt stress. Subsequent experiments demonstrated that LbHDZ14 is localized in the nucleus and negatively regulates salt gland density and salt tolerance by directly binding to the promoter of LbGDSL, a positive regulator of salt gland development. In conclusion, this study reveals the expression patterns of LbHDZ genes in L. bicolor, characterizes the functional mechanism of LbHDZ14, further elucidates the regulatory network underlying salt gland development, and provides candidate genes for enhancing crop salt tolerance.

Tissue-specific anthocyanin pigmentation is observed in rapeseed (Brassica napus L. AACC, 2n = 38) as well as in its ancestral diploids Brassica rapa (AA, 2n = 20) and Brassica oleracea (CC, 2n = 18). We previously identified the MYB genes BnaPAP2.A7b and BnaPAP2.C6a as key regulators of anthocyanin biosynthesis. Here we uncover an antagonistic regulatory mechanism in leaves involving their paralog BnaPAP2.C2. Unlike the pigmentation-associated genes, BnaPAP2.C2 is constitutively expressed in both green and purple leaves, regardless of anthocyanin levels. Its promoter contains two enhancers (463 and 486 bp) that synergistically regulate transcription. Competitive binding studies reveal that BnaPAP2.C2, although lacking activation capacity, sequesters BnaTT8 and outcompetes BnaPAP2.A7b, thereby suppressing anthocyanin biosynthesis. Under environmental stress, elevated expression of BnaPAP2.A7b promotes anthocyanin biosynthesis, whereas BnaPAP2.C2 is downregulated. This paralog-specific molecular antagonism provides new insight into the evolution of MYB-bHLH interaction specificity. Together, these findings uncover a novel inhibitory mechanism within the anthocyanin regulatory hierarchy of polyploid rapeseed, highlighting competitive binding as an evolutionary innovation driving functional diversification of duplicated MYB regulators.

Steroidal glycoalkaloids (SGAs) are a class of important secondary metabolites in tomato fruit development and ripening, which enhance fruit disease resistance but also act as antinutritional factors for human health. Although previous studies have reported that SGAs metabolism is influenced by light, the specific regulatory mechanisms remain insufficiently explored. This study demonstrates that light enhances the expression of the light-responsive transcription factor ELONGATED HYPOCOTYL 5 (HY5) and promotes the accumulation of bitter glycoalkaloids, whereas HY5 mutation suppresses this pathway and increases the synthesis of the non-bitter compound esculeoside A during fruit ripening. Further investigation reveals that HY5 directly binds to light-responsive elements in the promoters of glycoalkaloid biosynthesis genes, coordinating the metabolic shift from glycoalkaloid biosynthesis to detoxification metabolism. This provides a molecular basis for balancing tomato defense capability and fruit palatability.

In plants, C2 domain-containing proteins (C2DPs) constitute a large Ca²⁺-binding family involved in development and abiotic stress response. However, how it regulates the abscisic acid (ABA) signaling under chilling in rice is largely unknown. Here, we identified OsERG1, encoding a small C2 domain protein with binding Ca²⁺ in vitro, was induced obviously by cold stress and negatively regulated chilling tolerance in rice seedlings. An ABA receptor OsPYL10 was screened out from a yeast two-hybrid (Y2H) cDNA library using OsERG1 as bait. Furthermore, OsERG1 specifically interacted with OsPYL10 in both Ca²⁺- and ABA-dependent manners in vitro and in vivo. Moreover, both OsERG1 and OsPP2C09 interacted with the CL2 loop of OsPYL10 in the Y2H assay; OsERG1 was able to compete with OsPP2C09 for the interaction with OsPYL10 in the competitive in vitro pull-down assay. In addition, overexpression of OsERG1 and ospyl10 mutation showed a similar hyposensitive response of shoot growth to ABA application during the germination stage, suggesting the interrupting role of OsERG1 in the OsPYL10-OsPP2C09 module in rice. RNA-seq analysis confirmed that OsERG1 and OsPYL10 differentially regulated the expression of candidate genes in the ABA biosynthesis and ABA signaling, including OsNAC5, OsbZIP62, and OsbZIP46 under chilling. These findings provide the regulatory role of OsERG1 to the OsPYL10-OsPP2C09 module, and reveal new insight into the mechanism of chilling stress signaling and response in rice seedlings.