Plant, Cell & Environment最新文献

Anthocyanin is an antioxidant that enhances plant resilience against diverse biotic and abiotic stresses. Although high light intensity is known to enhance anthocyanin production, the underlying regulatory mechanisms are poorly understood. In this study, we identified an R2R3 MYB transcription factor MsMYB17 in alfalfa that promotes anthocyanin biosynthesis under both normal and high light conditions. Overexpression of MsMYB17 in alfalfa reduces plant height, internode length, and stem diameter without affecting plant internode number. Genetic and biochemical experiments demonstrate that MsMYB17 directly binds to and activates the promoters of MsDFR and MsANS, thereby promoting anthocyanin accumulation, which in turn reduces lignin content and inhibits plant growth under normal light conditions. Furthermore, high light enhances MsMYB17 expression and stabilises MsMYB17 protein by attenuating MsCOP1-mediated MsMYB17 degradation via the 26S proteasome pathway, thereby promoting anthocyanin production through the MsMYB17-MsDFR/MsANS module. Collectively, our findings reveal a light adaptation mechanism in alfalfa that integrates transcriptional and post-translational regulation of MsMYB17 to modulate anthocyanin biosynthesis. This study provides novel insights into the molecular mechanisms by which plants fine-tune specialised metabolism under fluctuating light conditions, and positions MsMYB17 as a potential target for enhancing stress resilience and forage quality in alfalfa.

Nitrogen (N) and phosphate (P) are essential macronutrients, yet their combined regulatory dynamics in rapeseed (Brassica napus) remain elusive. This study integrated transcriptomics, metabolomics, lipidomics and physiological phenotyping to dissect responses to N-P co-deficiency (-N-P), single deficiencies (-P, -N) and sufficiency (+N+P). Under -N-P, rapeseed exhibited severe growth inhibition (44.8% reduction in shoot biomass) and prioritised nutrient acquisition via transcriptional upregulation of root NRTs/AMTs (N uptake) and PHTs/PAPs (P scavenging) genes, sustaining higher N/P utilisation efficiency by root plasticity than single deficiencies. Photosynthesis was suppressed during deficiencies, with starch accumulation and TCA cycle perturbation indicating energy and carbon repartitioning. N-P imbalance (-P or -N) induced more severe carbon-metabolic dysregulation than dual deficiency. Crucially, lipid remodelling emerged as a central adaptive strategy: -P triggered phospholipid-to-galactolipid/sulfolipid conversion to conserve P, while -N diverted carbon toward signalling/storage lipids. -N-P attenuated these shifts but induced unique lipid species adjustments to maintain membrane stability. We propose an 'N-P Tumbler' model wherein balanced N-P supply stabilises metabolic homoeostasis and optimises carbon allocation. Our work uncovers transcriptionally orchestrated lipid metabolic trade-offs as key to N-P interplay, providing a framework for breeding nutrient-efficient crops and precision fertilisation strategies for sustainable agriculture.

Heat stress is a major abiotic stress that limits alfalfa (Medicago sativa L.) productivity. To test whether cytokinin-overexpressing engineered rhizobia could enhance heat tolerance, we inoculated alfalfa with modified rhizobia and evaluated their physiological and molecular responses. We found that inoculation with engineered rhizobia significantly increased trans-Zeatin content in alfalfa. Compared with control rhizobia-inoculated plants, engineered rhizobia-inoculated plants exhibited increased plant height, fresh/dry weight, relative water content, and photosynthetic efficiency (total chlorophyll and carotenoids), alongside reduced hydrogen peroxide (H₂O₂) and superoxide (O₂.^-) levels under heat stress. RNA-seq analysis revealed that engineered rhizobia upregulated heat stress-responsive genes in alfalfa, which was further verified by qRT-PCR. Metabolomics analyses showed significant alterations in phenylpropanoid, flavonoid, phenolic acid, and salicylic acid metabolic pathways in engineered rhizobia-inoculated plants under heat stress. Contrary to conventional approaches, our results demonstrate that cytokinin-overexpressing rhizobia not only enhance alfalfa heat tolerance but also activate multi-pathway stress responses. Collectively, these findings propose a novel strategy for developing heat-tolerant alfalfa through engineered rhizobia-mediated cytokinin biosynthesis, which helps to promote the development of sustainable alfalfa breeding for heat-tolerant varieties.

In response to pine wood nematode (PWN) invasion, pine trees can activate immune responses involving effector-triggered signalling, leading to redox imbalance and programmed cell death. However, such hypersensitive responses are also implicated in disrupting water conduction and accelerating wilting. Despite the identification of several PWN effectors, their roles in modulating host immunity remain unclear. Using integrated transcriptomic and metabolomic analyses across PWN infection timepoints, we revealed that the jasmonate (JA) pathway played a central role in the induction of defence responses; the expression levels of genes involved in JA biosynthesis and signal transduction changed markedly at different stages of PWN invasion. Through yeast two-hybrid screening, we revealed that the PWN effector BxCDP1 interacts with PmTIFY8, a key transcriptional regulator of the Jasmonate ZIM-domain (JAZ) family in the JA signalling pathway. We further demonstrated that this interaction occurs in the nucleus, attenuates reactive oxygen species (ROS)-mediated cell death, and modulates the expression of JA-responsive genes. Our results indicate that the interaction of BxCDP1 with JAZ proteins can impede the JA-mediated immune responses, which is a key link of PWN pathogenicity and provides information for genetic improvement to enhance resistance in pine trees.

In the Anthropocene era, climate change is increasingly subjecting the crops to overlapping abiotic stressors such as drought, elevated temperatures, and air pollution, thereby disrupting their physiological integrity and functional performance. This review synthesises current knowledge on responses of N₂-fixing plants to such stressors, focusing on core physiological processes and symbiotic nitrogen fixation via nodulation. The intricate interdependence between these traits is explored through the lens of altered source-sink relationships, which are highly sensitive to multifactorial environmental perturbations. A key emphasis is placed on the emerging concept of multi-stress interactions, where the convergence of abiotic stressors leads to nonlinear, often compounding effects on plant metabolism, growth, and resource allocation. The modulatory role of elevated atmospheric CO₂ (carbon fertilisation effect) is also examined, particularly in enhancing photosynthetic assimilation, and sustaining nitrogen-fixing potential under stress. By identifying critical knowledge gaps and integrating physiological, biochemical, and ecological insights, this review provides a holistic framework to understand legume function under compounded climate threats. Such understanding is pivotal for breeding climate-resilient legumes that not only withstand abiotic stresses but also sustain yield and soil health. This discourse directly contributes to Sustainable Development Goals (SDGs), notably SDG 2 (Zero Hunger) and SDG 13 (Climate Action), by highlighting the role of legumes in securing global food systems and ecological resilience in the face of climate uncertainty.

Pine wilt disease (PWD), caused by pine wood nematode (PWN, Bursaphelenchus xylophilus), severely threatens global pine forests. The Catharanthus roseus receptor-like kinase 1 L (CrRLK1L) family plays a critical role in plant defense against pathogen invasion. While recent studies have begun to elucidate the molecular mechanism of interaction between host trees and PWN, the function of CrRLK1L family members in gymnosperms remain poorly understood. Here, we analyzed the transcriptomic response of Pinus tabulaeformis to PWN infection and identified 58 CrRLK1L genes. Among them, PtTHESEUS1 (PtTHE1), a homolog of Arabidopsis THESEUS1, exhibited sustained transcriptional induction during PWN infection, as validated by RT-qPCR. Functional analyses showed that Arabidopsis theseus1 mutant was more susceptible to PWN, suggesting the involvement of PtTHE1 in host defense. The extracellular domain of PtTHE1 interact with BxEF1, a PWN secreted protein. BxEF1 was strongly expressed during early infection stage and predominantly localized in the dorsal gland of the PWN. Silencing of BxEF1 significantly impaired PWN feeding speed and reduced pathogenicity. In summary, BxEF1, a parasitism-promoting protein secreted by PWN, is perceived by PtTHE1, ultimately triggering host immunity. Our findings reveal a novel molecular mechanism of pine resistance to PWN and provide functional insights into CrRLK1L-mediated immunity in gymnosperms.

Brassica napus (rapeseed) is the world's most important oilseed crop, and its flowering time is a key determinant of regional adaptation and yield optimization. Nevertheless, the molecular links between specific MYB transcription factors, gibberellin (GA) biosynthesis, and flowering control in rapeseed have not been fully deciphered. Here, we identify BnaC04.MYB100 as a novel positive regulator of flowering time. Overexpression of BnaC04.MYB100 accelerated flowering, whereas CRISPR/Cas9-mediated knockout (bnac04.myb100) delayed it. Transcriptome and hormone analyses reveal that BnaC04.MYB100 activates key flowering-network genes and the GA biosynthesis pathway, elevating endogenous GA levels. The late-flowering phenotype of the Arabidopsis atmyb100 mutant is rescued by exogenous GA. Using dual-luciferase reporter, yeast one-hybrid, ChIP-qPCR, and EMSA assays, we demonstrate that BnaC04.MYB100 directly binds to the AACTACT motif in the promoter of BnaGA20ox3, a rate-limiting GA biosynthetic gene. Natural variation in the BnaC04.MYB100 locus is strongly associated with flowering time diversity in a rapeseed natural germplasm panel and shows evidence of artificial selection during modern breeding. Our findings establish BnaC04.MYB100 as a central integrator linking GA biosynthesis to flowering time, providing a valuable genetic target for optimizing reproductive development and yield potential in rapeseed breeding.

The cover image is based on the article Chemical Communication Between Plant and Microbe in the Phyllosphere by Xuanxuan Ma et al., https://doi.org/10.1111/pce.70314.