Biocontrol potential and antifungal mechanisms of Streptomyces misionensis TL-19 against Colletotrichum fioriniae causing kiwifruit anthracnose

Kiwifruit anthracnose caused by Colletotrichum fioriniae severely threatens global kiwifruit production and postharvest storage, while safe and efficient control strategies remain limited. Here, antagonistic actinomycete TL‑19 was isolated from kiwifruit rhizosphere soil and identified as Streptomyces misionensis using morphological, physiological-biochemical and phylogenetic analyses. Whole-genome sequencing revealed 33 secondary metabolite biosynthetic gene clusters (BGCs), supporting its antifungal capacity. The volatile organic compounds (VOCs) of TL-19 exerted strong antifungal activity against C. fioriniae . In vivo fumigation showed dose-dependent biocontrol efficacy on kiwifruit anthracnose, with optimal protection at 238.10 g/L. Microscopic observation indicated that TL-19 VOCs damaged pathogen hyphal morphology, cell wall and intracellular ultrastructure. Physiological assays demonstrated VOC fumigation increased membrane permeability and lipid peroxidation, and suppressed pathogen energy metabolism. GC‑MS analysis was conducted on VOCs from strain TL‑19 and several candidates were used for antifungal activity assessment; among these compounds, 1‑heptanol exhibited the strongest antifungal activity, with an EC₅₀ of 0.076 μL/mL. Transcriptomic analysis further validated that 1-heptanol interfered with lipid homeostasis and energy metabolic pathways of C. fioriniae . Collectively, S. misionensis TL-19 is a promising biocontrol candidate. Its multi-target antifungal mechanisms provide theoretical foundations for developing biofumigation-based green strategies for large-scale postharvest kiwifruit anthracnose management.