Plant, Cell & Environment最新文献

Chilling is an important abiotic stressor that significantly affects cucumber production. Melatonin (MT) modulates chilling responses by interacting with multiple signalling molecules; however, the molecular link between MT and nitric oxide (NO) in cucumbers under chilling stress remains elusive. Herein, we found prolonged chilling stress induced the accumulation of endogenous NO, whereas overexpression of MT biosynthesis gene N-acetylserotonin methyltransferase (CsASMT), with higher endogenous MT content, significantly increased chilling tolerance of cucumbers with decreased accumulation of NO via upregulation of the relative expression of S-nitrosoglutathione reductase gene (CsGSNOR), accompanied by decreased membrane lipid peroxidation and reactive oxygen species (ROS) accumulation. Moreover, we identified a transcription factor zinc finger of Cucumis sativus 10 (CsZAT10), and found CsZAT10 could directly bind to the promoter of CsGSNOR. Furthermore, we found CsZAT10 overexpression enhanced cucumber chilling resistance by directly activating CsGSNOR expression to mediate NO homoeostasis, whereas the suppression of CsZAT10 obviously decreased the chilling tolerance and CsGSNOR expression in cucumber induced by MT. Overall, our results demonstrate that MT enhances chilling tolerance in cucumber by regulating the CsZAT10-CsGSNOR-NO module.

Cadmium (Cd) is a toxic metal that accumulates in plants to inhibit growth and enters the food chain to harm human health. Although Cd accumulation and tolerance in plants have been extensively analysed, their regulation is less understood. Here, we identify a stress-responsive receptor-like kinase (OsSRK) involved in rice Cd accumulation and tolerance. Our results show that OsSRK expression was strongly induced by Cd treatment. OsSRK overexpression decreased while its silencing or mutations increased both Cd accumulation and Cd-induced leaf chlorosis in rice. OsSRK is a close homologue of MULTIPLE SPOROCYTE 1 (MSP1), which controls sporogenic development with its TAPETUM DETERMINANT1 (TPD1)-LIKE 1 A (OsTDL1A) ligand. OsSRK interacts with OsTDL1B, an OsTDL1A homologue, in both yeast and plant cells. Like OsSRK, expression of OsTDL1B was induced by Cd treatment, and mutations of OsTDL1B enhanced both Cd accumulation and Cd-induced symptoms in rice. These results strongly support that OsTDL1B acts as a ligand for the OsSRK receptor kinase in Cd stress signalling. Comparative transcriptome and proteome profiling support that OsSRK plays a critical role in rice Cd accumulation and tolerance through the regulation of genes in Cd accumulation and oxidative stress responses.

As plants grow taller, increasing conductive pathlength imposes hydraulic resistance, challenging the maintenance of water transport to leaves. While tip-to-base conduit widening along the stem helps mitigate this resistance, theoretical models and empirical data suggest that stem widening alone is insufficient to fully compensate. Here, we explore whether leaf length could contribute to maintaining hydraulic conductance by influencing vessel diameters in the stem. Across a diverse set of angiosperm species, we found that leaf length strongly predicts vessel diameter at the petiole base, and that petiole vessel diameter, in turn, scales positively with vessel diameter at the twig tip. These relationships imply that longer leaves are associated with wider conduits in the stem, potentially boosting stem-wide permeability. Simple fluid dynamic models show that the steep rate of conduit widening in angiosperm leaves plausibly buffers the resistance costs of increased leaf length. Because vessel diameter scales with the fourth power of conductance, modest increases in leaf length, and thus stem conduits, could lower the resistance not buffered by conduit widening in the stem. Leaf length during height growth may serve as a key mechanism in maintaining hydraulic supply, complementing conduit widening in the stem.

Flowering is essential for plants to reach the survival of species and flowering is influenced by many environmental factors. However, trithorax group (TrxG) mediated epigenetic modification mechanisms of Physalis grisea under low temperature on flowering remain largely unknown. Here, we report that TrxG core member ULTRAPETALA1 (PgULT1) inhibits flowering in P. grisea by interacting with Polycomb Group (PcG) member LIKE-HETEROCHROMATIN-PROTEIN 1 (PgLHP1) and transcription factor DNA-BINDING-ONE-FINGER 3.4 (PgDOF3.4) to regulate H3K4me3 and H3K27me3. PgULT1 overexpression delayed flowering, yet flowering was relatively promoted under low temperatures. Similarly, PgDOF3.4 confers delayed flowering by transcribing PgULT1, PgLHP1, and FLOWERING LOCUS C (PgFLC). Protein interaction assays indicated that PgULT1, PgDOF3.4 and PgLHP1 can interact with each other, enhance PgFLC transcription and suppress FLOWERING LOCUS T (PgFT) transcription. Genetic evidence demonstrated that PgULT1 and PgLHP1 inhibit flowering by depositing H3K4me3 and H3K27me3 at the PgFLC and PgFT transcription start sites, respectively. PgULT1, PgDOF3.4 and PgLHP1 expression are suppressed under low temperatures, leading to reduced H3K4me3 and H3K27me3 modifications on PgFLC and PgFT promoters, thereby promoting flowering. Collectively, the functional interactions between epigenetic modifiers and transcription factors reveal a cooperative mechanism between TrxG and PcG to respond to low temperatures and promote flowering in P. grisea.

Plants produce a wide array of secondary metabolites, also known as natural products (NPs), with diverse chemical properties. These compounds play crucial roles in plant development and defence against environmental stress. DNA methylation has emerged as a key regulator of secondary metabolism by modulating gene expression at the transcriptional level. By providing a new source of variation, DNA methylation holds great potential for enhancing NP accumulation, offering valuable insights for scientists and breeders alike. However, our understanding of current research trends in this area is limited. In this respect, we summarise the most recent findings on the roles of DNA methylation in the biosynthesis of three major classes of important NPs-pigments, flavour compounds and medicinal substances, including methylating and demethylating enzymes, the global methylation dynamics and the dual regulation of DNA methylation in different genomic regions or sequence contexts on gene expression. We also discuss alternative splicing regulated by DNA methylation in plants. Finally, we highlight key unanswered questions and propose potential future research directions to further unravel the regulatory mechanisms of DNA methylation in NP biosynthesis. This knowledge will facilitate the development of innovative strategies for improving plant quality and increasing NP production.

Soil salinity largely impacts plant growth and development worldwide. Uncovering important regulators involved in plant salt tolerance is crucial for helping plants survive in saline land through genetic engineering. Nonetheless, potential key genes directly related to tolerance to soil salinity have not been fully identified. Through a soil-based genetic screen, we obtained the salinity-tolerant mutant tos1 (tolerance of salt 1), which exhibited glossier and greener leaf morphology under salt stress. tos1 mutation localized at the functionally uncharacterized gene BOUNDARY OF ROP DOMAIN3 (BDR3). A defect in BDR3 results in enhanced resistance to salt stress, accompanied by lower Na⁺ accumulation and water deprivation mediated by a decreased transpiration rate, due to the increased accumulation of cuticular wax, especially VLCFAs and alkanes. BDR3 has no lipase activity, but the fatty acid metabolic process was strongly affected, and glycerolipid hydrolysis was enhanced in tos1; more fatty acids were consumed for wax synthesis, strengthening the cuticular wax maintenance. Our results demonstrate that BDR3 is a novel and negative regulator involved in plant salt tolerance, controlling cuticular transpiration and ion balance depending on its biofunctions in wax synthesis through fatty acid metabolic reprogramming. The study could provide a new molecular basis for the improvement of the regulatory network of wax biosynthesis and plant salt tolerance.

Photoperiod regulates flowering time and maturity in soybean, thereby determining yield performance and latitudinal adaptation. However, the molecular network through which photoperiod regulates flowering remains incompletely elucidated. Here, we identify two BBX family transcription factors, BBX32a and BBX32b, that act as positively regulators flowering under long-day (LD) conditions in soybean. We demonstrate that BBX32a and BBX32b can form both homologous and heterologous dimers. The bbx32a and bbx32b mutants exhibit significantly delayed flowering compared to wild-type W82. However, the bbx32a bbx32b double mutants flower at a similar time to the single mutants, suggesting that the BBX32a-BBX32b heterodimer plays a central role in regulating soybean flowering. E3 and E4 upregulate the transcription of BBX32a and BBX32b, which repress E1 transcription to promote flowering under LD conditions. Genetic evidence demonstrates that BBX32a and BBX32b regulate flowering time, completely dependent on functional E3, E4 and E1 family genes. Four haplotypes of BBX32a were identified in 1295 soybean accessions; BBX32a^Hap3 exhibits significantly reduced nuclear accumulation relative to BBX32a^Hap1. The BBX32a^Hap1 allele is predominantly fixed in cultivated soybeans, whereas BBX32a^Hap2 and BBX32a^Hap3 alleles remain largely unexploited. Collectively, our findings identify novel genetic targets for developing novel soybean cultivars adapted to high-latitude regions, thereby maximising yield potential.

The plant circadian clock synchronizes endogenous rhythms with environmental cues, ensuring optimal growth and development. While the transcription-translation feedback loops (TTFLs) model provides a foundational framework for circadian system, the mechanisms that precisely control the diel and circadian oscillation of key clock genes remain incompletely understood. In particular, the expression of PSEUDO-RESPONSE REGULATOR 9 (PRR9), a dawn-phased core oscillator, needs to be rigorously regulated for proper clock function and environmental responsiveness. Here, we systematically dissected the cis-regulatory architecture of PRR9 promoter using LUC reporter transgenic lines with large-fragment deletions and site-directed mutagenesis. We identified distinct cis-elements that govern PRR9 transcript abundance, rhythmicity and environmental responsiveness. Notably, we discovered a previously uncharacterized 27-bp sequence without any known circadian motifs, which is essential for PRR9 transcriptional rhythmicity, challenging the common view that clock-controlled cis-elements alone determine clock gene expression. These findings refine the TTFLs model and strengthen the link between PRR9 promoter architecture and its role in responding to light and temperature signals to achieve growth advantage.