Plant, Cell & Environment最新文献

Global climate warming has significantly increased plant diseases prevalence. In subtropical regions, high temperature frequently co-occurs with bacterial wilt caused by Ralstonia solanacearum, creating compound stress conditions that severely compromise eggplant productivity. However, the molecular mechanisms governing eggplant's response to combined heat and pathogen stress remain poorly characterized. In this study, we conducted the temperature analyses of Guangzhou, China, and isolated a thermotolerant strain PSS219-GZ under high temperatures in eggplant. Phenotypic analysis of eggplants inoculated with PSS219-GZ at different temperature, indicated that PSS219-GZ have maximal pathogenicity at 37°C. SmWRKY6 is a WRKY transcription factor activated by both high temperatures and Ralstonia solanacearum infection. Genetic evidence from silencing of SmWRKY6 via VIGS in eggplants and overexpression of SmWRKY6 in tomato demonstrated that SmWRKY6 is essential for enhancing resistance to Ralstonia solanacearum under high-temperature stress. SmWRKY6 directly binds to and transcriptionally activates the SmPR1b promoter, forming a key regulatory node in bacterial wilt resistance pathways. This study provides novel insights into plant responses to combined heat and R. solanacearum stress and highlights potential resistance genes for mitigating compound stress effects.

Common mycorrhizal networks (CMN) formed by arbuscular mycorrhizal (AM) fungi are critical pathways for plant nutrition and interplant nutrient transfer. However, their role in mediating sexually asymmetric interactions in dioecious plants remains poorly understood, especially under nitrogen (N) deficiency. Using in vivo ¹⁵N leaf-labeling in Populus cathayana saplings, we quantified N transfer via CMN between sexes and linked them to root traits. We found that intersexual pairs facilitated CMN-mediated N transfer from male to female saplings; this transfer was markedly amplified under low N conditions. When N availability shifted from sufficient to deficient conditions, males shifted from a conservative strategy to an AM fungi-dependent 'outsourcing' strategy (characterized by higher mycorrhizal colonization rates), whereas females transitioned from a relatively weak root foraging strategy to an enhanced one (with greater specific root length and specific root area). This strategic divergence promoted sexually asymmetric N transfer via CMN, leading to optimized nutrient use efficiency at the population level. These results highlighted a previously unrecognized role of CMN in facilitating sexually asymmetric nutrient interactions, offering a mechanistic framework to improve both productivity and sustainability in dioecious plantations on nutrient-poor soils.

As the primary energy source for photosynthesis, light also serves as a critical environmental cue regulating developmental plasticity through photomorphogenesis. While extensive research has characterized light-mediated shoot development, including hypocotyl de-etiolation, cotyledon expansion and chloroplast biogenesis, emerging evidence demonstrates that light signals also profoundly influence the root. Phenotypic analyses of photoreceptor mutants have revealed that roots, like above-ground tissues, perceive and respond to light signals through sophisticated signalling networks. This review synthesizes current understanding of core light signalling cascades and the systemic mechanisms facilitating shoot-to-root signal transmission. We highlight recent advances in understanding how light quality and intensity modulate root development through hormonal crosstalk and transcriptional reprogramming. By integrating molecular mechanisms with agronomic applications, we further provide a detailed summary of the application of plant photobiology. It suggests practical strategies for optimizing root development through light-mediated control.

Plant uridine diphosphate-dependent glycosyltransferases (UGTs) play a key role in plant growth and defense mechanisms. Tung oil tree (Vernicia fordii), suffers from disease caused by Fusarium oxysporum f. sp. Fordiis (Fol). However, little is known about how to enhance the resistance mechanism. In this study, we observed significant enrichment of flavonoid biosynthesis pathway in V. fordii roots following Fol infection, including myricetin-glucoside and kaempferol-glucoside. Based on transcriptomic analysis, we screened 11VfUGTs showing elevated expression in response to Fol infection. Through correlation analysis (Pearson's r) between flavonoid metabolite level and 11VfUGTs transcription levels, we discovered that increased flavonol glycoside accumulation post-infection was associated with VfUGT87H9 activity. Furthermore, the VfUGT87H9 gene exhibited strong root-specific expression and rapid transcriptional induction upon Fol challenge. In vitro enzymatic assays confirmed VfUGT87H9's ability to catalyze myricetin glucosylation, producing myricetin-glucoside. Transgenic plants overexpressing VfUGT87H9 demonstrated enhanced pathogen resistance compared to control plants, with OE-VfUGT87H9 roots accumulating significantly higher myricetin-glucoside level. In vitro assays showed that myricetin-glu inhibits mycelial growth and host infection by Fol. Our findings established VfUGT87H9 as a flavonoid glucosyltransferase that positively regulates plant disease resistance by maintaining flavonol glycosides homeostasis. This study advances our understanding of flavonoid-mediated plant-pathogen interactions and metabolic defense strategies.

This study investigated the mechanisms of cadmium (Cd) tolerance and root exudate-mediated soil activation in mulberry (Morus alba L.), a promising species for phytoremediation. Hydroponic experiments with Cd-tolerant seedlings exposed to 5 and 50 mg/L Cd revealed a biphasic concentration-dependent response. Low Cd induced negligible biological effects, whereas high Cd triggered substantial disturbances across multiple biological levels, including morphological alterations, physiological dysregulation and disrupted elemental accumulation patterns. Metabolomic profiling indicated that Cd stress significantly altered the secretion patterns of 17 root exudate metabolites in mulberry, exemplified by the upregulation of sucrose, lactose and 4-acetylbutyric acid, and the downregulation of β-alanine and myo-inositol. Further pathway enrichment analysis linked these differential metabolites to 17 metabolic pathways, with carbohydrate and amino acid metabolism as the main Cd-responsive pathways, suggesting their core role in mediating mulberry's Cd resistance. Root exudates enhanced soil Cd mobilisation in a positive concentration-dependent yet negative time-dependent manner. Consequently, mulberry adapts to Cd stress via metabolic reprogramming of root exudates-a strategic trade-off that serves a dual role by enhancing plant tolerance while simultaneously increasing Cd bioavailability in the soil. This insight provides a foundational framework for phytoremediation, centred on exudate management and the selection of stress-tolerant varieties.

The mechanisms of selenium (Se) oxyanion transformation in endophytic bacteria remain poorly understood, which limits their application in biofortification and phytoremediation. Here, we investigated these mechanisms using the plant-growth-promoting (PGP) endophyte Erwinia sp. PSI-03. Under 2 mM selenite stress, the strain intracellularly and extracellularly produced spherical selenium nanoparticles (SeNPs; ab57 nm average diameter). Multi-omics analyses revealed that these SeNPs were formed through parallel enzymatic (mediated by sulfite reductase, cysI) and non-enzymatic (via glutathione and l-cysteine) reduction pathways. Additionally, γ-glutamyl-Se-methylselenocysteine was identified as a key organo-selenium metabolite. Selenite exposure induced extensive reprogramming of the metabolome and transcriptome, highlighting key roles for glutathione metabolism and stress response systems related to cell wall/membrane maintenance, oxidative phosphorylation, two-component signaling systems, and DNA repair. Intriguingly, selenite stress concurrently stimulated bacterial synthesis of PGP compounds, including the auxin precursor indole-3-pyruvate, the defense hormone salicylic acid, and acetate. Consistent with this, under selenite-free and high-selenite (12 mg kg^-1 Se) conditions, inoculation with Erwinia sp. PSI-03 significantly promoted tea plant growth. Compared to uninoculated controls, the leaf biomass increased by 52.8% and 51.7%, and the total biomass by 82.9% and 49.6%, respectively. These findings establish a paradigm where endophytic bacteria simultaneously detoxify Se and promote plant health, offering a robust strategy for agricultural and environmental Se management.

The direct response of stomata to temperature (DRST, the response with the leaf-to-air vapor gradient, Δw, held constant) is poorly studied due to the difficulty of keeping Δw constant while changing leaf temperature. Most published data suggest a positive response, though the mechanisms behind such a response are unknown. We propose that a hydraulic mechanism should contribute to the DRST, wherein temperature decreases the viscosity of water, increasing hydraulic conductance and thereby increasing leaf water potential, which in turn drives stomatal opening. Because the sensitivity of leaf water potential to changes in hydraulic conductance should be proportional to transpiration rate and hence to Δw, this mechanism predicts a stronger positive DRST at higher Δw than at lower Δw. We tested this prediction by measuring the DRST at two different values of Δw, in six diverse angiosperm species. Our results are consistent with the hypothesis that a hydraulic mechanism contributes to the DRST, though the response varies widely across species, and in three of six species the effect of Δw was far stronger than predicted from theory, suggesting a role for other mechanisms in enhancing the effect of Δw on the DRST.