Plant, Cell & Environment最新文献

Retrograde transport from endosomes to the trans-Golgi network (TGN) is essential for intracellular trafficking, yet its molecular mechanism remains poorly understood. In Fusarium graminearum, 10 Rab GTPases associated with the Golgi-associated retrograde protein (GARP) complex were identified through immunoprecipitation followed by mass spectrometry (IP-MS). Among these, only the deletion of FgRAB6 disrupted the proper localisation of the GARP complex to the TGN. FgRab6 directly interacts with the GARP subunit FgVps52 via a conserved Q73 residue, which is critical for fungal growth and pathogenicity. Notably, this Q73-dependent interaction is evolutionarily conserved across eukaryotic species. Upon GTP activation, FgRab6 recruits FgVps52 to the TGN, thereby facilitating the assembly of the GARP complex through the sequential recruitment of additional subunits, including FgVps51, FgVps53 and FgVps54. The fully assembled GARP complex subsequently recruits the retromer complex and ensures the precise localisation of the SNARE proteins FgSnc1, FgTlg1 and FgTlg2 at the endosomes and the TGN. Disruption of this pathway severely compromises fungal development and virulence. Collectively, these findings identify a FgRab6-GARP-retromer-coordinated vesicle trafficking pathway that mediates the retrograde transport of SNARE proteins, which is critical for the pathogenicity of F. graminearum. This work provides new mechanistic insights into vesicular transport and highlights potential targets for antifungal intervention.

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.

Symbiotic interactions between legumes and rhizobia enable nitrogen fixation under low nutrient conditions. The establishment and function of symbiotic interactions require coordinated changes in gene expression in both the host and the microbe. Circular RNAs (circRNAs) are endogenous gene-specific molecules that can regulate transcription and translation in response to biotic and abiotic stress through various mechanisms. Our objective was to identify circRNAs specifically generated in response to nutrient supply and rhizobial symbiosis. We sequenced nodulated and non-inoculated roots from Lotus japonicus and identified a total of 11,923 putative circRNAs originating from 5,290 nuclear-encoded transcripts in Lotus roots under low or high nutrient supply and nodulated roots. Of those, 58 circRNAs were specific and present in most nodulated root samples. We identified circRNAs for more than half of the known symbiosis-associated genes, including SymRK, CCamK, and Cyclops, and showed that several of those genes also generated circRNAs in Phaseolus vulgaris nodules. We validated select circRNAs potentially involved in regulating symbiosis and predicted miRNA recognition elements (MREs) created only by the backsplice junctions of circRNAs. These putative backsplice-generated MREs could represent an additional mechanism by which circRNAs may modulate the abundance and translation of mRNAs in competing endogenous RNA-regulatory networks.

Climate change represents a major global challenge, intensifying abiotic stresses such as drought, salinity and temperature extremes, that severely constrain productivity and threaten food security. To survive under such fluctuating and adverse environments, plants depend on intricate hormonal signalling networks that coordinate growth regulation, resource allocation and stress adaptation. Among these, strigolactones (SLs) have emerged as integrative regulators that bridge developmental control with environmental responsiveness, thereby enhancing plant resilience to climate-induced stresses. Initially discovered as rhizospheric signals influencing parasitic weed germination and symbiotic associations, SLs are now recognized as multifunctional phytohormones regulating shoot branching, root system architecture, senescence and reproductive growth. SLs encounter in extensive crosstalk with other hormones notably abscisic acid, auxins and cytokinins to modulate physiological and molecular responses under stress. This review consolidates recent advances in understanding the role of SLs as central mediators of plant adaptation to climate-induced abiotic stresses, emphasizing their integrative signalling roles and interactions with other phytohormones. It also explores emerging molecular, genetic and biotechnological strategies targeting SL pathways for enhancing stress resilience. Unravelling the complex SL signalling network delivers key conceptual inputs for providing climate-smart crops capable of sustaining productivity and stability under the increasing pressures of global climate change.

Arbuscular mycorrhizal (AM) fungi are common root-associated endophytic fungi that enhance host plant growth and induce resistance against various stresses. However, their role in mediating insect resistance in vegetable crops remains poorly understood. In this study, the effects of AM fungi inoculation on growth and insect resistance against Spodoptera litura in four representative vegetable species (tomato, pepper, cucumber, and lettuce) were investigated. Lettuce (Lactuca sativa), which exhibited the strongest mycorrhiza-induced resistance, was subsequently selected for detailed mechanistic investigation through physiological and biochemical measurements, phytohormone profiling, gene expression analysis, and targeted metabolomics. AM fungi-inoculated lettuce exhibits both elevated growth and pronounced insect resistance. During the early stages of herbivory, AM fungi rapidly activates the jasmonic acid (JA) signaling pathway, leading to increased levels of 12-oxo-phytodienoic acid (OPDA), JA, and bioactive jasmonyl-isoleucine (JA-Ile), as well as the upregulation of key JA biosynthetic gene LsOPR3 and the defense-related gene LsPI. Mycorrhizal inoculation also mitigates lipid peroxidation induced by insect feeding and enhances the activities of antioxidant enzymes (superoxide dismutase and catalase) in leaves. Targeted metabolomic analysis reveales that AM fungi significantly altered secondary metabolism in lettuce, particularly promoting the accumulation of L-tryptophan (L-Trp) and its derivatives (such as methyl indole-3-acetate and indole-3-carboxaldehyde) under insect stress, alongside notable increases in phenylpropanoid and flavonoid pathway metabolites. Exogenous application assays further confirmed that JA treatment strongly induced the expression of insect defense-related polyphenol oxidase genes (LsPPO3, LsPPO4) and enhanced resistance but suppressed plant growth. In contrast, L-Trp treatment elevated LsPPO3 and LsPPO4 expression while maintaining biomass accumulation. These results show that AM fungi inoculation promotes lettuce growth and insect resistance through elevating JA signaling and L-tryptophan accumulation. Moreover, this study emphasizes the potential role of L-Trp in improving vegetable crops biomass and insect defense.