Plant, Cell & Environment最新文献

Increasing evidences show plant growth-promoting rhizobacteria (PGPR) benefit legume-rhizobium symbiosis, and iron-based nanoparticles (FeNPs) act as rhizobia microenvironment stabilizers. However, few studies explored if their combination exerts synergistic effects on the symbiosis in legume. Here, we compared the effects of FeNPs, Pseudomonas rhizovicinus M30-35, and their co-application (Fe + M) on alfalfa growth, nitrogen fixation, root metabolites, and rhizosphere microbiome. Compared with FeNPs and M30-35, Fe + M increased shoot height, root length, root activity, chlorophyll content, and net photosynthetic rate (Pn) by 63.2% and 45.4%, 61.1% and 70.6%, 56.2% and 47.1%, 20.1% and 18.6%, and 41.1% and 30.6%, respectively; the nodule number, nitrogenase activity, ureide content, and leghemoglobin content rose by 29.6% and 31.4%, 58.5% and 78.7%, 20.4% and 15.1%, and 9.7% and 12.4%, respectively. Metabolomic analysis showed that Fe + M enhanced the accumulation of benzenoid compounds in roots, while microbial co-occurrence network analysis indicated reduced complexity and connectivity of rhizosphere bacterial and fungal communities. Importantly, core microbes, such as Hydrogenophaga, Nocardioides, unidentified_Mitochondria, and Scedosporium, were positively associated with benzenoid compounds, which contribute to nutrient cycling in the rhizosphere. Our findings demonstrate that FeNPs and PGPR strain together achieve synergistic effects on the nitrogen fixation in alfalfa.

Orchids rely on symbiotic microorganisms for nutrient acquisition throughout their life cycle, from seed germination to plant maturity. In the terrestrial orchid Gymnadenia conopsea, beneficial Pseudomonas species have been previously identified as associated with seed germination and enriched in protocorms. Yet, the specific metabolites that mediate this microbial recruitment remain unknown. In this study, integrated transcriptomic and metabolomic analyses revealed that seed imbibition activates the phenylpropanoid biosynthesis along with starch and sucrose metabolism pathways, resulting in increased secretion of trehalose and sinapyl alcohol. These metabolites were found to attract Pseudomonas sp. and facilitate their colonisation. We further assessed the effects of these metabolites in the presence of the germination-promoting fungus Ceratobasidium sp. GS2, with or without Pseudomonas. Our results indicated that trehalose enhanced protocorm development when combined with the fungus, and this effect was significantly strengthened by the addition of Pseudomonas. In contrast, sinapyl alcohol promoted protocorm development only when both the fungus and Pseudomonas were present. These findings uncover a metabolite-mediated synergy that coordinates beneficial microbes to orchestrate early development in G. conopsea, advancing our understanding of metabolite-fungus-bacteria interactions and benefiting cultivation practices.

Phytophthora nicotianae is a plant-pathogenic oomycete, posing a serious threat to global agriculture due to its highly destructive infections and challenges in management. To explore a biologically based disease management strategy, we investigated Streptomyces ardesiacus HL-06, which produces phenazine-1-carboxamide (PCN), a potent anti-oomycete metabolite that effectively suppresses the growth of P. nicotianae in vitro and reduces tobacco black shank severity by over 80% under field conditions, surpassing the efficacy of commercial fungicides. Mechanistically, we identified CDC48, a AAA+ ATPase essential for mitochondrial homeostasis, as the direct molecular target of PCN. Drug affinity responsive target stability (DARTS), molecular docking, and isothermal titration calorimetry revealed that PCN binds to CDC48's ATPase domain, thereby disrupting mitochondrial protein quality control. This interaction leads to mitochondrial cristae loss, ATP synthase inhibition, and reactive oxygen species (ROS) accumulation, ultimately triggering oomycete apoptosis. This is the first report of a phenazine compound targeting a eukaryotic AAA+ ATPase, revealing a novel mode of action against oomycete pathogens. Our findings integrate microbial ecology with chemical biology, positioning PCN as a promising eco-friendly candidate for sustainable plant disease management.

Pyrabactin resistance1-like (PYL) receptors are essential for activating abscisic acid (ABA) signalling and play critical roles in plant growth and development. Melon (Cucumis melo) is a horticultural crop cultivated worldwide, yet the molecular functions of CmPYL in melon remain largely unexplored. We performed in situ hybridisation and transcriptomic analysis to investigate the expression patterns of the CmPYL gene in melon. CmPYL5 exhibits specifically high expression levels during the development of melon ovules and fruits. Overexpression of CmPYL5 in melon significantly promotes fruit ripening, advancing 3-5 days compared to WT. Transcriptomic analysis showed that fruit ripening-related genes are significantly altered in the CmPYL5-Oe melon. Silencing of CmPYL5 and overexpression of a Protein Phosphatase-type 2C A6 (CmPP2CA6) gene, which is a negative regulatory component in the ABA signal pathway, both delayed the fruit ripening and affected the accumulation of ethylene, ABA, carotenoids and chlorophyll in melon. Protein interaction assays showed that CmPYL5 and CmPP2CA6 directly interacts in the cell membrane, leading to the inhibition of CmPP2CA6 phosphatase activity. The transcription factors CmABF2 and CmABF4 directly bind to CmPP2CA6 promoter and then activate its transcription. These findings illustrate a novel CmPYL5-CmPP2CA6 gene regulation pathway modulating melon fruit ripening.

Meconopsis integrifolia is a famous alpine flower widely admired for its striking yellow flowers, yet the molecular mechanisms underlying this unique pigmentation remain poorly understood. Through integrated metabolomic and transcriptomic analyses across three key floral developmental stages, we identified 87 flavonoids, with flavonols constituting the major differential metabolites. Kaempferol 3-β-D-glucopyranoside, quercetin 3-O-sophoroside and quercetin 3-O-galactoside were the predominant flavonols, exhibiting a progressive decrease during petal development. We further cloned two pivotal biosynthetic genes, MiFLS2 and MiDFR6, and western blot analysis and subcellular localisation revealed that both proteins are distributed in the cytoplasm and nucleus. Functional verification in transgenic tobacco revealed that MiFLS2 overexpression increased flavonol accumulation while suppressing anthocyanin biosynthesis, leading to lighter-coloured flowers. In contrast, MiDFR6 overexpression coordinately up-regulated both flavonol and anthocyanin pathways but ultimately promoted redder pigmentation, indicating distinct regulatory roles. Critically, we uncovered a possible multilayer regulatory mechanism: The expression of MiFLS2 is negatively correlated with that of upstream flavonoid genes and MiDFR6, hinting at a possible feedback inhibitory role. Conversely, MiDFR6 overexpression is associated with the coordinated upregulation of multiple structural genes in the flavonoid biosynthesis pathway, implying a putative positive regulatory function. Metabolite analysis confirmed that pelargonidin-3-O-rutinoside, cyanidin-3-O-rutinoside, and kaempferol 3-β-D-glucopyranoside are key contributors to flower colour variation. Ultimately, the high MiFLS2/MiDFR6 expression ratio in M. integrifolia suggests a key factor in controlling the biochemical fate of dihydroflavonols, conferring yellow coloration. Our findings provide novel insights into the competitive and regulatory mechanisms controlling flower colour in alpine plants.

Aquaporins (AQPs), key members of the major intrinsic protein (MIP) superfamily, have emerged as pivotal regulators of plant responses to diverse abiotic stresses. Beyond their natural role as water channels, AQPs function as integrators of transport, signaling, and acclimation. This review synthesizes current knowledge on their structural diversity, stress-specific isoform expression, and multilayered regulation by transcription factors, phytohormones, and signaling molecules. We highlight the modulation of AQP activity through post-translational mechanisms such as phosphorylation, gating, and trafficking, and emphasize the central role of plasma membrane intrinsic proteins (PIPs) in hydraulic adjustment under drought, salinity, and temperature stress. By linking AQPs with antioxidant systems, ion channels, and stress signaling pathways, we underscore their function as natural hubs of adaptation. We further evaluate their potential in crop improvement through genetic manipulation, including CRISPR-based strategies, while identifying key knowledge gaps in isoform-specific functions, subcellular dynamics, and interactions with soil microbiota. Taken together, AQPs represent promising targets for enhancing crop resilience in the face of climate change.

Small signaling peptides have emerged as central mediators of biological communication within and between species. In this review, we propose and define the concept of trans-kingdom peptides (TKPs) as short, bioactive peptides produced by one organism that exert specific physiological effects in another, often across taxonomic kingdoms. We summarize recent progress in identifying plant- and microbe-derived TKPs that function in symbiosis, parasitism, plant-microbe interactions, herbivory, and host-virus dynamics. TKPs modulate host defense, developmental programs, microbial community structure, and abiotic stress responses through highly specific interactions with conserved receptor systems. We highlight known peptide families mediating legume-rhizobia nodulation, nematode parasitism, and microbial immune suppression, as well as newly discovered viral- and insect-derived peptides that manipulate plant immunity. We discuss how they shape coevolutionary dynamics between hosts and interacting organisms. Finally, we outline current challenges and potential applications of TKPs in agriculture, biomedicine, synthetic biology, and environmental sustainability. Altogether, by framing their emerging properties and biological significance, we aim to provide a conceptual foundation and encourage interdisciplinary research into this expanding frontier of plant biology and inter-organismal communication.