Plant, Cell & Environment最新文献

Insect-derived molecular cues can prime plant defences against herbivore attack. The genes that are sensitive to priming, and how their expression changes on the scale of days, have not been fully resolved. Moreover, priming may affect interactions with insects that are not the source of the priming cue. We primed tall goldenrod (Solidago altissima) plants by exposure to the volatile emission of a specialist herbivore, the goldenrod gall fly (Eurosta solidaginis) then subjected the plants to 48 h of herbivory from an unrelated generalist, corn earworm (Helicoverpa zea). Using RNA sequencing, we identified transcriptome-wide gene expression patterns between exposed and unexposed plants. We identified biotic stress-associated genes that were more abundant during herbivory in primed plants, including defence-related transcription factors, thaumatin-like receptors and chitinases. We observed a surprising rise and fall in expression of hundreds of defence-related genes in a 48-h phase in primed damaged plants only. Our results support the hypothesis that primed defences are stronger than typical induced defences and suggest that primed defences target herbivores in the short term. We show that the threat cue from a specialist can affect plant defences against an unrelated herbivore.

Tartary buckwheat, valued for its nutritious and medicinal quercetin. Following two independent domestication events, distinct quercetin accumulation patterns have emerged between the southwestern (SL) and northern (NL) landrace populations. However, the genetic mechanisms underlying these metabolic divergences remain elusive. Here, we identified the transcription factor FtNAC2 through genome-wide association study (GWAS) of quercetin content in 480 accessions of Tartary buckwheat. Haplotype analysis identified two single nucleotide polymorphisms (SNPs) in the FtNAC2 promoter that defined three major haplotypes, with higher promoter activity and gene expression observed in Hap2. Functional characterization revealed that FtNAC2 promotes quercetin accumulation in Tartary buckwheat hairy roots and potentially serves as a multifunctional regulator influencing both drought tolerance in buckwheat and seed size in Arabidopsis. Transcriptome co-clustering and pull-down mass spectrometry (MS) indicated FtNAC52 as a potential regulatory partner of FtNAC2. DNA affinity purification sequencing (DAP-seq) and quantitative reverse transcription PCR (qRT-PCR) analyses demonstrated that FtNAC2 promoted quercetin biosynthesis by upregulating FtF3'H and FtF3'5'H genes. Collectively, our results elucidated how FtNAC2 influences quercetin content variation in Tartary buckwheat, providing molecular insights into the differential quercetin accumulation between cultivated populations.

OsAAI1 belongs to the HPS_like subfamily of the AAI_LTSS superfamily, yet the molecular mechanism by which it regulates root development under osmotic stress remains unclear. In this study, we found that overexpressing OsAAI1 significantly promoted rice root system growth. Specifically, the primary root length, lateral root number, lateral root density and adventitious root count in the overexpression line (OE19) markedly exceeded those in the wild type (ZH11) and the osaai1 mutant. Consistent with this phenotypic enhancement, the root IAA content in OE19 was substantially higher than in ZH11 and osaai1. We further demonstrated that exogenous IAA application compensated for the root growth defects in the osaai1 mutant. Under PEG-induced osmotic stress, OE19 exhibited the most extensive and densely distributed root system, and exogenous IAA also rescued the inhibited growth of the osaai1 mutant. Mechanistically, we identified an interaction between OsAAI1 and the MADS-box transcription factor OsMADS25. This interaction enhanced the transcriptional expression of two key osmotic stress tolerance genes, LAX1 and OsBAG4. Furthermore, it upregulated the auxin biosynthesis gene OsYUC4 while suppressing the auxin inhibitory factor OsIAA14. This coordinated gene regulation promotes the auxin signalling pathway, thereby stimulating root growth and enhancing osmotic stress tolerance. Collectively, our findings indicate that OsAAI1 and OsMADS25 fulfil critical functions in rice osmotic acclimation by orchestrating downstream gene expression and modulating the auxin pathway.

Leaf spot disease, caused by the fungal pathogen Alternaria alternata f. sp. mali, poses a severe threat to apple production. Pathogenesis-related (PR) genes are crucial for plant immunity, yet their regulatory networks remain poorly understood. Here, we report that MdDREB2A, a transcription factor known for its role in abiotic stress, negatively regulates apple resistance to A. alternata by suppressing the expression of MdPR10 genes. We demonstrated that MdDREB2A overexpression plants exhibited increased susceptibility to A. alternata infection, whereas its knockdown conferred enhanced resistance. Based on DAP-seq analysis, we identified three MdPR10 genes as direct targets of MdDREB2A. This direct repression was confirmed by ChIP-qPCR, EMSA, and dual-luciferase assays, which showed that MdDREB2A binds to the promoters of MdPR10s to inhibit their transcription upon pathogen infection. Furthermore, functional studies revealed that MdPR10 proteins possess antifungal activity, and their overexpression enhanced resistance in apple leaves. Consequently, in MdDREB2A overexpression plants, the suppression of MdPR10s leads to diminished antifungal resistance. This study establishes MdDREB2A as a negative regulator of defense against A. alternata in apple, which operates by repressing the expression of three pathogenesis-related genes, thereby proposing a new strategic direction for developing resistant apple cultivars.

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.