Botrytis cinerea poses severe postharvest losses in horticultural products, while synthetic fungicides raise food safety concerns. This study developed a GRAS-compliant antifungal strategy using vapor-phase Cymbopogon citratus essential oil (EO). GC-MS revealed citronellal (17.06%) as the dominant bioactive compound. The EO exhibited superior vapor-phase activity against B. cinerea, with EC₅₀ of 14.69 µg/mL (mycelial growth) and MIC of 7.81 µg/mL (spore germination), significantly lower than direct-contact efficacy (p < 0.05). Mechanistic analysis revealed a tripartite mode of action—rapid membrane disintegration (48% electrolyte leakage within 4 h), suppression of ROS defense enzymes (SOD/CAT/POD inhibition > 50%), and disruption of mitochondrial energetics (SDH activity reduced by 58.1%)—which induced irreversible cellular collapse. This multi-target strategy mitigates resistance development, a key limitation of single-mode fungicides. In commercial-scale trials, EO fumigation (125 µg/mL) reduced cherry tomato decay by 81.9–92.6% during 28-day storage, while maintaining firmness (15.9% higher than control) and nutritional quality (titratable acidity (TA) and total sugar content (TSC)). Notably, the vapor-phase EO also exhibited potent inhibitory activity against the spore germination of rubber tree powdery mildew (EC₅₀: 3.19 µg/mL), demonstrating its broad-spectrum antifungal potential. This finding significantly expands the application scope of C. citratus EO from postharvest preservation to preharvest crop protection. This work provides a scalable, residue-free alternative to synthetic fungicides for industrial postharvest applications.

Gray mold, caused by the necrotrophic fungus Botrytis cinerea, is a devastating disease responsible for substantial global crop losses. The escalating threat of fungicide resistance and environmental concerns necessitates the development of eco-compatible control alternatives. In this study, we investigated the antifungal efficacy of methyl 2-methylbutyrate (M2M), a microbial volatile organic compound (mVOC), against B. cinerea, and elucidated the underlying physiological, transcriptomic, and metabolomic responses. Our results demonstrated that M2M significantly inhibited mycelial growth in a dose-dependent manner, with an EC₅₀ value of 3.49 μL/plate. Scanning electron microscopy revealed severe ultrastructural damage in M2M-treated hyphae, characterized by localized swelling, shriveling, and irregular bending. Physiological assays indicated that M2M significantly upregulated the activities of antioxidant enzymes, including catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), while significantly reducing malondialdehyde (MDA) content, suggesting that M2M triggers an oxidative challenge to which B. cinerea responds by activating its antioxidant defense system, thereby suppressing lipid peroxidation and the activities of key metabolic enzymes, such as succinate dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G6PDH), and lactate dehydrogenase (LDH). These findings suggest that M2M treatment is associated with perturbations in cellular redox homeostasis and central carbon metabolism in B. cinerea. Transcriptomic profiling identified 3664 differentially expressed genes (DEGs), predominantly enriched in carbon metabolism, glyoxylate and dicarboxylate metabolism, redox pathways, and ribosomal biogenesis. Notably, M2M exposure significantly perturbed the transcriptional levels of ROS-scavenging genes (e.g., CAT, POD, GPX, PRX, and GST) and various transcription factors. Untargeted metabolomics revealed 1041 differentially accumulated metabolites (DAMs), with lipids and lipid-like molecules representing the most significantly altered class. Integrated multi-omics analysis revealed that M2M treatment was associated with coordinated changes in lipid metabolism, central carbon metabolism, and redox balance. This study provides mechanistic insights into the antifungal action of M2M and suggests that M2M warrants further investigation as a potential candidate for postharvest gray mold management.

Rubber tree (Hevea brasiliensis) anthracnose, caused by multiple species within the genus Colletotrichum, is a globally significant disease that seriously threatens the sustainable development of the natural rubber industry in China. Characteristic symptoms, including foliar necrosis, defoliation, and shoot blight, culminate in significant economic losses for producers. This review systematically summarizes the epidemiological patterns and damage, pathogen genetic diversity, the molecular pathological mechanisms underlying Colletotrichum–rubber tree interactions, and chemical and biological control strategies. Furthermore, an integrated disease management (IDM) framework is proposed, and key directions for future research are outlined to provide a theoretical foundation for the scientific prevention and control of rubber tree anthracnose in China.

TasA gene, encoding a functional amyloid protein critical for biofilm formation and antimicrobial activity, was cloned from the endophytic strain Bacillus amyloliquefaciens BS-3, isolated from rubber tree roots. This study identified the shortest functional TasA variant (483 bp, 160 aa) reported to date, featuring unique amino acid substitutions in conserved domains. Bioinformatics analysis predicted a signal peptide (1–27 aa) and transmembrane domain (7–29 aa), which were truncated to optimize heterologous expression. Two prokaryotic vectors (pET28a and pCZN1) were constructed, with pCZN1-TasA expressed solubly in Escherichia coli Arctic Express at 15 °C, while pET28a-TasA formed inclusion bodies at 37 °C. Purified recombinant TasA exhibited potent antifungal activity, achieving 98.6% ± 1.09 inhibition against Colletotrichum acutatum, 64.77% ± 1.34 against Alternaria heveae. Notably, TasA completely suppressed spore germination in C. acutatum and Oidium heveae Steinmannat 60 μg/mL. Structural analysis via AlphaFold3 revealed that truncation enhanced protein stability. These findings highlight BS-3-derived TasA as a promising biocontrol agent, providing molecular insights for developing protein-based biopesticides against rubber tree pathogens.