Plant, Cell & Environment最新文献

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.

Rice blast, caused by the fungus Magnaporthe oryzae, severely impacts rice yield and quality. Plants possess intricate molecular mechanisms to recognize and respond to pathogen infections. In this study, we demonstrated that the infection of M. oryzae induces the expression of prePSK, the precursor of the endogenous small peptide, phytosulfokine, in rice. The exogenous application of active PSKα significantly enhances rice resistance to rice blast. Conversely, the PSK septuple mutant exhibits reduced resistance against M. oryzae, indicating the involvement of PSK in the defense response against rice blast. Through genetic and biochemical evidence, we identified OsPSKR2 as a functional PSK receptor that is essential for PSK-mediated rice blast resistance. Intriguingly, the overexpression of OsPSKR2 promotes the expression of pathogenesis-related (PR) genes and increases reactive oxygen species (ROS) production, thus strengthening rice blast resistance without negatively affecting plant growth or yield. Moreover, we established that the OsPSK-PSKR2 signaling cascade, whose activity depends on OsTPST-mediated PSK tyrosine sulfation, is necessary for immunity against both rice blast and leaf blight. Thus, our study elucidates the role of PSK-PSKR module in broad-spectrum disease resistance in rice.

Lysine deficiency in staple crops like maize, rice, and wheat remains a major cause for global protein malnutrition, underscoring the urgent need for effective biofortification strategies. This review critically examines recent advances in enhancing lysine content, spanning conventional breeding and metabolic engineering to cutting-edge precision genome editing. While conventional breeding, exemplified by Quality Protein Maize, has improved lysine levels, it is often constrained by yield and quality trade-offs. Metabolic engineering strategies, including overexpression of lysine biosynthetic genes, suppression of catabolic genes, and modification of storage proteins, have achieved substantial lysine enrichment but face regulatory and consumer acceptance challenges due to their transgenic nature. The advent of CRISPR/Cas technology now enables precise, transgene-free editing of key enzymes such as DHDPS, AK, and LKR/SDH offering a powerful alternative, though concerns regarding off-target effects and pleiotropy remain. While integrating multi-omics with AI-driven predictive modelling can optimise metabolic flux for higher lysine yield, coupling next-generation genome editing with speed breeding offers a transformative route to develop high-lysine, high-yielding crops for sustainable nutritional security.