Plant, Cell & Environment最新文献

In rice, some varieties exhibit high resistance to planthoppers. However, the mechanisms underlying this superior resistance remain largely unknown. Here, we found that compared to the variety Yuefeng (YF), brown planthopper (BPH, Nilaparvata lugens) exhibited significantly less feeding and weight gain, slower development, and lower survival rate and fecundity on the variety JN08. JN08 plants had higher phosphorylation levels of constitutive and BPH-induced mitogen-activated protein kinase (MPK) 4 and 6 than YF plants. They also showed quicker and stronger jasmonic acid (JA) and jasmonoyl-isoleucine response to BPH at early stages of infestation as well as higher constitutive and/or BPH-elicited levels of H₂O₂, most tested phenolamides and some tested flavonoids than YF plants. Bioassays showed that four of phenylamides, N-cinnamoylputrescine, N-p-coumaroylagmatine, N-p-coumaroyl-N'-feruloylputrescine and N-feruloyltyramine, all of which had higher levels in JN08 plant than YF plants, had a significant effect on the survival and/or growth of BPH nymphs. Moreover, overexpressing OsPAL1 (phenylalanine ammonia-lyase1), a gene encoding a rate-limiting enzyme in the phenylpropanoid biosynthesis pathway, in rice significantly reduced BPH performance. These results demonstrate that phenylpropanoid-associated metabolites, such as phenylamides and flavonoids, probably regulated by OsMPK4/6-mediated JA and H₂O₂ signalling pathways, play an important role in regulating rice resistance to BPH.

Copper is essential yet phytotoxic when excessive, and polypropylene microplastics (PP-MPs) are increasingly co-occurring with Cu in soils, but their mechanistic impact on woody ornamentals remains unclear. Jasminum sambac in Cu spiked soil across a PP-MPs gradient and found a dose-dependent, non-monotonic modulation of Cu toxicity. PP-MPs accumulated on root surfaces, shifting Cu partitioning along the soil-root-shoot axis: an intermediate load reduced shoot Cu and translocation, lowered membrane lipid peroxidation, and was accompanied by coordinated adjustment of glutathione redox metabolism (GSR, G6PD, PGD) and GSH turnover (GGT, GGCT). Transcriptomics indicated that moderate PP-MPs partially restored genes for chlorophyll biosynthesis (CHLI/CHLH/CHLM) and light-harvesting (Lhcb1/2), aligning with improved photosynthesis and chlorophyll a/b balance. However, high dose PP-MPs weakened this protection: root Cu rebounded, antioxidant enzymes (SOD/POD) dropped below control levels, PetC expression remained low, and chlorophyll a/b imbalance reoccurred. At a higher load, protection weakened root Cu rebounded, SOD and POD fell below control levels, PetC associated electron transport remained constrained, and Chl a/b imbalance re-emerged. The data suggest that PP-MPs act as both an interfacial sorptive buffer and a regulator of redox photosynthetic networks, informing risk assessment of metal-microplastic co‑contamination in soils.

Soybean is a globally important economic and food crop, whose production is often constrained by drought stress, posing a serious threat to yield and quality. Genomic selection (GS) has become a core technology in modern breeding, effectively enhancing breeding efficiency. However, conventional prediction models mainly rely on additive genetic effects and fail to adequately incorporate non-additive factors such as epistasis, limiting further improvements in prediction accuracy. In this study, a genome-wide epistatic analysis of soybean drought tolerance identified 3594 protective interaction pairs. Incorporating significant epistatic SNP pairs into six genomic prediction models resulted in comparable and substantial improvements in prediction accuracy across all models (by 24%). Furthermore, integration of AlphaFold2-based protein structure prediction and transcriptional regulatory analyses validated the biological reliability of protective epistatic pairs, effectively reducing the risk of false positives. Network construction and functional enrichment analyses further revealed that these epistatic pairs participate in coordinated protein structural interactions and are enriched in key biological pathways. Haplotype analysis confirmed the critical regulatory role of non-additive effects in soybean drought tolerance. Collectively, this study establishes a comprehensive evidence chain from molecular mechanisms to breeding applications, demonstrating that integrating epistasis into GS can effectively enhance prediction performance for drought tolerance in soybean. These findings provide novel research strategies for the genetic analysis of complex traits and efficient breeding.

Hydroxycinnamoyl tyramine conjugates are phenolamides produced by plants in response to pathogen attack and biotic stresses. Their proposed mechanisms of action include cytotoxicity towards pathogens, cell wall reinforcement to restrict pathogen proliferation, and signaling activity to trigger general stress responses. Here, we engineered the production of the tyramine conjugates p-coumaroyltyramine (CT) and feruloyltyramine (FT) in Arabidopsis to gain insight into their mode of action. Co-expression of feedback-insensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase and tyrosine decarboxylase increased tyramine content. Additional expression of tyramine hydroxycinnamoyltransferase led to de-novo production of CT and FT, which were found as soluble and cell-wall-bound forms. FT was associated with lignin in stems. The growth of pathogenic Pseudomonas syringae was reduced in rosettes of the Arabidopsis CT- and FT-producing lines compared to wild type. These lines also exhibited increased transpirational water loss in excised rosettes. Transcriptomic analysis of transgenic lines grown under normal conditions revealed alterations in the expression of genes associated with the biological circadian clock. These changes led to a reduction in flavonoids and an early flowering phenotype. Important changes in the expression of genes related to abiotic stress such as drought, cold, heat, and hypoxia potentially contribute to reduced growth of P. syringae in engineered Arabidopsis.

Upon attack by insect herbivores, plants can perceive herbivore-derived physical and chemical cues and rapidly reallocate their resources for growth and defense. Insect herbivory specifically induces rapid systemic down-regulation of plant photosynthesis, characterized by whole-plant systemic stomatal closure. However, its underlying mechanism is not fully understood. Here, we found that the simulated herbivory (wounding + oral secretion, WOS) in tomato local (treated) leaflets triggered a decrease of more than 45.0% in stomatal conductance (g_s) in the systemic (adjacent and distal) uninjured leaflets 3 h after the treatment. Local WOS treatment also induced local upregulation of jasmonic acid (JA) biosynthesis genes and systemic JA accumulation in wild-type tomato. Consistently, the systemic stomatal closure response was severely compromised in JA synthesis-deficient mutants (spr2 and spr8). Grafting experiments with wild-type and spr8 mutant proved that the local JA biosynthesis triggered by WOS is essential for systemic stomatal closure. In addition, JA-mediated H₂O₂ bursts in the systemic guard cells is vital for systemic stomatal closure triggered by local WOS treatment. Our findings reveal a crucial role of local JA biosynthesis and systemic JA-mediated H₂O₂ bursts in systemic stomatal responses triggered by insect herbivory in tomato.

Developing drought-resilient crops requires a precise understanding of molecular signalling in the root, the primary organ encountering drought. This study unravelled novel genetic loci regulating drought tolerance by exploiting the natural variation in seedling root growth of Arabidopsis thaliana under PEG-induced drought stress. Through a genome-wide association study of 207 worldwide A. thaliana ecotypes from regions with varied rainfall, 68 protein-coding genes were identified with the top 50 SNPs. Functional enrichment and network analyses demarcated key processes involved in stress tolerance, including DNA repair, tRNA editing, protein folding, cell cycle regulation, stress granule assembly and the pyridoxal 5'-phosphate (PLP) salvage pathway. Expression level polymorphisms, promoter cis-element variations and amino acid substitutions associated with phenotype and climate were identified. Reverse genetic evaluation using T-DNA insertion knockout/knockdown mutants confirmed the involvement of candidate genes: AT1G06690 (PLP pathway), AT4G26990, RBP45C (stress granules), ACD55.5 (protein folding), PCMP-A4 (AT1G14470; RNA editing), SKS6, ANAC094 (cell wall remodelling) and INCENP (cell cycle), with seedling drought tolerance. Specifically, knockdown of AT1G06690 resulted in higher root hydrogen peroxide accumulation, highlighting the importance of the PLP pathway in mitigating oxidative stress. These molecular insights offer new biotechnological and breeding tools to enhance crop drought tolerance by modulating root traits.

Lipid remodelling is a fundamental component of plant responses to environmental stress and development, yet its regulation in fast-growing aquatic plants remains poorly understood. Here, we investigated how abscisic acid (ABA) regulates triacylglycerol (TAG) accumulation and fatty acid (FA) composition in the duckweed Lemna minor. A 3-day treatment with 1 µM ABA induced a 2.9-fold increase in TAG content, accompanied by extensive remodelling of plastidial and extraplastidial membrane lipids. Reduced monogalactosyldiacylglycerol (MGDG) likely served as a FA source for TAG synthesis. Transcript analyses revealed strong induction of diacylglycerol acyltransferase (DGAT) genes, catalysing the final step of TAG formation, and repression of fatty acid desaturase (FAD) genes, resulting in a marked reduction in polyunsaturated FA levels. Confocal imaging confirmed substantial lipid droplet accumulation in both fronds and chloroplast-containing roots. Notably, this sustained ABA-induced TAG accumulation was unique to L. minor, with no comparable response observed in other duckweed species or in Arabidopsis under identical treatment. These findings reveal a species-specific ABA-driven lipid remodelling pathway in duckweed, linking phytohormone signalling to carbon storage in aquatic plants.

The phyllosphere, the aboveground interface between plant leaves and their microbial residents, plays a vital yet underappreciated role in crop productivity. While root- and soil-associated microbiomes are well-studied, the ecological assembly and yield-related effects of host-mediated phyllosphere microbial communities remain largely understudied, particularly under field conditions. This study investigates the phyllosphere microbiomes of sorghum cultivars resistant and susceptible to nutrient deficiency, focusing on how host genotype mediates microbial community assembly, keystone enrichment, and yield outcomes. The β-diversity of phyllosphere microbiomes differs significantly between resistant and susceptible cultivars, with resistant lines also showing more modular co-occurrence networks enriched in keystone taxa. These cultivars supported a higher abundance of keystone beneficial specialists (KBS), predominantly affiliated with Bacteroidia and Bacilli, and their abundance was positively correlated with yield. In contrast, susceptible cultivars exhibited lower and more taxonomically dispersed KBS, with a negative correlation between KBS and yield. Structural equation modeling suggested that while soil properties consistently promoted yield across cultivars, the impact of KBS on yield was genotype-dependent. These findings reveal a host-driven microbial mechanism linking phyllosphere composition to yield performance and highlight KBS as potential targets for microbiome-informed breeding or foliar microbial applications to improve crop productivity in sustainable systems.

Pennycress (Thlaspi arvense) is an intermediate oilseed bioenergy crop under development for growth over winter in the Midwest. Crucial work remains to domesticate and optimize pennycress for incorporation into cropping systems and to increase its resilience to stresses. We found that increased planting density reduces biomass and hastens time to flowering and maturity in field-grown pennycress, both of which are associated with plant shade avoidance responses (SAR). We confirmed that pennycress elongates when exposed to foliar shade and elevated ambient temperatures (28°C), physiological responses controlled by the red-light photoreceptor PHYTOCHROME B. We applied knowledge of the PHYTOCHROME B signalling pathway from Arabidopsis thaliana to identify target genes to mutate to suppress shade-avoidance responses during interseeding and to alter tissue responses to elevated temperatures. Mutating PHYTOCHROME INTERACTING FACTOR 7 reduced organ elongation to competition and heat cues and retained a compact rosette when exposed to shade and/or elevated temperature. Crucially, yield and oil content were unaltered in pif7. Furthermore, indicators of plant health, including hue, chlorophyll indices, and root system architecture, were improved in the pif7 mutant compared with the wild type. This showed that plant architecture and physiological health can be uncoupled under competition and heat stress, supporting our efforts to attenuate morphological responses to environmental cues. We propose that mutating PIF7 is a strategy to reduce SAR, improve pennycress performance at high densities during interseeding establishment in standing crops, and address the impacts of a warming climate on plant architecture.