Plant, Cell & Environment最新文献

Wheat is a staple crop crucial for global food security, but its production is significantly affected by salt stress. Exploring natural genetic diversity in wheat can identify ways to improve salt tolerance. We subjected five wheat genotypes: Mocho de Espiga Branca (enhanced tissue tolerance), Fretes (tissue tolerance), Wyalkatchem and Westonia (salt exclusion) and Westonia Nax1 (enhanced salt exclusion), to 150 mM NaCl for 8 days. We measured changes in biomass, photosynthesis, chlorophyll content, Na⁺/K⁺ ratios and protein abundance. Mocho maintained growth despite high tissue Na⁺, showing physiological tolerance supported by differential regulation of mitochondrial proteins, central carbon metabolism, the GABA shunt and compatible solutes. Mitochondrial complexome profiling revealed salt-induced instability of 2-oxoglutarate dehydrogenase complex (OGDC) and a hydroxyglutarate synthase orthologue (HglS). In vitro assays confirmed subtle but significant OGDC activity and stability differences in Mocho, which also retained higher TCA cycle enzyme levels in vivo. Whole-plant treatment with the OGDC inhibitor succinyl phosphonate reproduced salt-like reductions in chlorophyll and biomass, particularly in Mocho. These findings highlight distinct strategies of tissue tolerance and salt exclusion in wheat, emphasising OGDC's role in Mocho's salt tolerance and pointing to metabolic pathways that could improve tissue tolerance traits and support sustainable agriculture.

Gene pyramiding in crop varieties offers a promising strategy to achieve sustainable production and reduce reliance on pesticides. However, stacking resistance genes without understanding their biological functions may result in transient protection. Although numerous studies have mapped loci associated with resistance to biotic stresses, the underlying molecular mechanisms remain poorly characterised. Resistance genes are often involved in pest/pathogen recognition, whereas quantitative trait loci (QTLs) may act in other steps of plant immunity such as signalling and defence pathways. In parallel, specialised metabolites have attracted growing attention as key defence components, acting as antimicrobial or repellent agents. While both fields encounter challenges to precisely decipher plant defence mechanisms, making use of metabolomics on segregating populations could bypass some of these limitations. In this review, we introduce an approach based on the identification of metabolic QTLs within populations where resistance QTLs segregate, enabling the detection of genomic co-localisations between both types of QTLs. This integrative framework can reveal specific metabolic signatures associated with resistance, thus refining hypotheses on the mode of action of resistance QTLs. Ultimately, elucidating the genetic architecture of specialised metabolism in relation to quantitative resistance will inform on more effective combinations of defence mechanisms for breeding resistant varieties.

Soft rot is a major disease restricting the production of colored calla lily, with severe impacts on their ornamental, commercial, and market value, caused by infection with Pectobacterium carotovorum. This study investigated the involvement of long noncoding RNAs (lncRNAs) in the soft rot response of colored calla lily leaves. Transcriptome sequencing of infected leaves identified 35,175 potential lncRNAs. Differential expression analysis revealed significant upregulation or downregulation of numerous lncRNAs following infection, indicating their potential involvement in the plant's immune response to P. carotovorum. Among these, LNC86472 was identified as a differentially expressed lncRNA that functions as a potential endogenous target mimic (eTM) for miR166a. Meanwhile, miR166a directly targets homeodomain-leucine zipper 15 (HB15) transcripts, which activates immune responses and restricts pathogen invasion. Functional studies involving the transient expression and silencing of LNC86472 and HB15 in colored calla lily leaves demonstrated that overexpression resulted in enlarged lesion sizes and compromised plant immune responses, while silencing them led to the opposite effect. Notably, infection-induced increases in jasmonic acid levels were associated with the downregulation of LNC86472. Further analysis showed that MYC2 directly binds to the LNC86472 promoter to repress its expression. These results suggest that jasmonic acid (JA)-mediated downregulation of LNC86472 releases miR166a, thereby facilitating miR166a-mediated cleavage of HB15 transcripts. This study provides new insights into the role of lncRNAs in the soft rot infection process of colored calla lily.

The accumulation of nano/microplastics (N/MPs) in wetlands has significant physiological effects on plants, which often simultaneously suffer herbivore attacks. However, how N/MPs interfere with interspecific interactions between wetland plants and herbivores remains poorly understood. Here, we pre-exposed Phragmites australis to N/MPs (100 nm/2 μm; 10, 50 and 100 mg/L) for 1 week, followed by co-exposure to N/MPs and Thrips sp., to determine the effect of N/MPs on the plant's insect resistance. NP exposure significantly increased P. australis biomass upon thrips attacks, while MPs exhibited no effects on reed growth. The exposure of 100 mg/L NPs alleviated root oxidative stress, feeding damage and photodamage caused by thrips and triggered stronger hormone signal transduction than MPs. In particular, 100 mg/L NPs upregulated transcription factors and DNA methylation to activate defence priming in roots, as well as histone modification in leaves. Metabolomics verified that P. australis accumulated more jasmonic acid, insect-resistant metabolites, indole-3-acetic acid, auxin and central metabolism-related metabolites, which help plants to defend against herbivores and facilitate growth. These results elucidate the molecular mechanism by which NPs mediated plant defence priming against herbivores, contributing to a better understanding of the ecological impacts of emerging contaminants and providing new insights into wetland conservation and ecological management.

The Na⁺/H⁺ antiporter SALT OVERLY SENSITIVE 1 (SOS1) is a key component of Na⁺ exclusion and plant salt tolerance. Although previous studies have suggested that SOS1 functions in both the root apex and mature root zone, their contributions remain unclear due to limited methodological resolution and originated mostly from transcriptional analysis. Here, we performed isotopic tracing techniques to visualize and quantify Na⁺ exclusion. Real-time imaging of shoot-applied ²²Na⁺ showed that ²²Na⁺ gradually disappeared from roots in wild-type (WT) plants, whereas it did not in sos1 mutants. To confirm that this reduction reflected active Na⁺ exclusion to the rhizosphere, we used the Microelectrode Ion Flux Estimation, which revealed significant Na⁺ efflux at the mature root zone of WT plants following shoot Na⁺ application, while no such efflux was observed at the root apex or in either root zone of sos1 mutants. Further quantification using a radioisotope-based method showed that approximately 90%-95% of Na⁺ derived from both the phloem and xylem was excluded from WT roots, primarily via SOS1, with the mature root zone identified as the major contributor. This study provides visual and quantitative evidence for the crucial contribution of SOS1 to Na⁺ exclusion in the mature root.

The white-backed planthopper (WBPH; Sogatella furcifera) is a destructive phloem-feeding hemipteran that significantly limits rice productivity by depleting assimilates and transmitting viral pathogens. Although melatonin is recognised as a multifunctional plant-signalling molecule, its defensive role against WBPH remains inadequately characterised. In this study, we demonstrate that exogenous melatonin application markedly enhances rice resilience to WBPH through coordinated regulation of growth, defence signalling, antioxidant activity and ionic homoeostasis. Melatonin increased seedling survival by up to 384% and reduced early WBPH colonisation by 93%, while delaying symptom onset under sustained pest pressure. Oxidative damage was mitigated by decreasing H₂O₂ and O₂•- accumulation by 54% and 23%, respectively, elevating relative water content by 38%, and reducing electrolyte leakage by 44%. Melatonin also stimulated anthocyanin biosynthesis via transcriptional activation of PAL, CHS, F3H, DFR and ANS, and promoted endogenous melatonin synthesis by upregulating TDC, T5H, ASMT and SNAT. Phytohormonal profiling revealed increased levels of abscisic acid (82%) and salicylic acid (SA, 29%), alongside activation of jasmonic acid and SA pathways through induction of LOX, AOS, AOC, PR1, PR2 and NPR1. Antioxidant capacity was enhanced via elevated activities of APX, CAT, POD, SOD, ABTS and DPPH. Furthermore, melatonin restored Ca²⁺ homoeostasis and stimulated GABA shunt metabolism, resulting in a 97% increase in succinate accumulation. These findings highlight melatonin's multifaceted role in conferring protection against WBPH by integrating physiological, biochemical and molecular defences, underscoring its potential as a bio-regulatory agent to enhance rice resistance against phloem-feeding insects.

Ammonium (NH₄ ⁺) is a crucial nitrogen (N) form for plant growth. The functions of ammonium transporters (AMTs) in mycorrhizal plants and their role in mediating ammonium uptake and regulating N metabolism in blueberry are not fully understood. In this study, 19 VcAMT genes were identified in blueberry. Tissue-specific expression analysis revealed that nine VcAMT members exhibited root-predominant expression patterns, with significant upregulation following inoculation with the O. maius BL01. Notably, VcAMT14 was specifically upregulated during mycorrhizal symbiosis and under N regulation, and subcellular localisation analysis confirmed its protein is located at the plasma membrane. Functional analysis in yeast demonstrated that VcAMT14 mediates NH₄⁺ transport activity. Furthermore, inoculation with O. maius BL01 enhanced rhizosphere soil sucrase activity, soil urease activity, soil phosphatase activity, N content, GS/GOGAT enzyme activity, and the expression levels of related genes in blueberry plants, while simultaneously reducing soil pH. Conversely, VcAMT14 silencing resulted in significantly reduced NH₄⁺ content, GS/GOGAT enzyme activities, and the expression of related genes, along with an increase in the pH of the hydroponic nutrient solution. These findings suggest that VcAMT14 plays a crucial role in regulating N response in blueberry under ERMF symbiosis, providing important insights into the mycorrhiza-mediated N uptake mechanism.

Phosphate (Pi) is an essential macronutrient for plant development that is often limited in soil. Plants have evolved dynamic biochemical, physiological and morphological adaptations to cope with Pi deficiency, known as the Pi starvation response (PSR). While many components of the PSR have been well-characterised, less is known about how metabolic homoeostasis is re-established upon Pi resupply, particularly tissue- and time-specific adaptations. Here, we applied label-free quantitative proteomics to quantify protein-level changes in Arabidopsis thaliana shoots and roots following Pi resupply after prolonged Pi deprivation. Sampling at 1 h and 48 h time-points, we captured immediate signalling and metabolic responses, along with longer-term recovery processes. Early responses prioritised metabolic adjustments restoring Pi pools via enhanced glycolysis and energy production, followed by later shifts toward anabolism. Several key enzymes, including ALTERNATIVE OXIDASE 1 A, FRUCTOSE-BISPHOSPHATE ALDOLASE 5 and subunits of PHOTOSYSTEM I exhibited tissue-specific and time-dependent regulation. Our findings reveal dynamic phases of metabolic reprogramming during recovery from Pi starvation, and identify candidate proteins as potential targets for enhancing Pi uptake- and use-efficiency in crops. While hydroponic liquid culture enabled precise control of Pi availability, soil responses may be further influenced by heterogeneity and other root interactions.

Leaf variegation represents a striking natural phenomenon where distinct pigmentation patterns develop within individual leaves, yet the underlying molecular mechanisms remain poorly understood. Here, we investigated yellow stripe formation in the ornamental bamboo Sasaella kogasensis 'Aureostriatus' using integrated physiological, cellular, and multi-omics approaches. Yellow stripe development followed a 240-day progression of spatially restricted senescence, with yellow zones showing accelerated chloroplast degradation and reduced chlorophyll content. Ultrastructural analysis revealed progressive chloroplast shrinkage, thylakoid swelling, and osmiophilic granule accumulation in yellow zones. Multi-omics profiling identified flavonoids as predominant differentially accumulated metabolites (16.79% of 1227 detected), with 177-fold upregulation of chrysoeriol O-malonylhexoside, alongside 6951 differentially expressed genes showing coordinated downregulation of photosynthesis and upregulation of chlorophyll degradation pathways. We identified three key regulatory genes (SkSGR, SkNAC021, and SkNAC29) whose roles were validated through transgenic Arabidopsis experiments demonstrating premature senescence and chlorophyll degradation. Hormone profiling revealed zone-specific accumulation of abscisic acid, salicylic acid, and jasmonic acid precursors. Our findings demonstrate that yellow stripe formation involves coordinated regulation of chloroplast degradation, flavonoid biosynthesis, and senescence-associated networks, providing molecular insights into natural leaf variegation patterns.

Macrophomina phaseolina (Tassi) Goid. is a fungal pathogen that causes charcoal rot (CR) disease in various legumes, including soybean. To date, no reliable resistance gene sources have been identified in soybean or other legumes to combat M. phaseolina. The apoplast is a critical region where intense molecular cross-talk occurs between plants and pathogens, and the outcome of their interactions is determined in this compartment. Here, we employed label-free quantitative (LFQ) proteomics to investigate the changes in soybean root apoplast during M. phaseolina infection. We have detected several secreted proteins of M. phaseolina and differential accumulation of soybean-secreted proteins during infections. Glycome analysis and callose deposition assays have revealed changes in soybean root cell wall compositions during M. phaseolina infection. AlphaFold 2 (AF2) analysis was instrumental in revealing several sequence-unrelated structurally similar (SUSS) effectors and effectors with novel structural folds secreted by M. phaseolina. AlphaFold multimer (AFM) analysis of candidate-secreted proteins from soybean and M. phaseolina has predicted cysteine and serine protease-inhibitor complexes. We have validated these interactions using molecular dynamics (MD), inhibition assays and competitive activity-based protein profiling (ABPP) approaches. Therefore, our work provides insights into Soybean-M. phaseolina interactions in the root apoplast and potential candidates for engineering resistance.