Streptomyces hanimojiang sp. nov. AMJ-169, a Novel Biocontrol Agent Producing Volatile (1S)-(-)-α-Pinene, Suppresses Strawberry Postharvest Rot Caused by Neopestalotiopsis rosae

Postharvest rot caused by Neopestalotiopsis rosae severely threatens strawberry production globally. Here, a novel species of Streptomyces was isolated and identified through polyphasic taxonomy, for which we propose the name Streptomyces hanimojiang sp. nov. AMJ-169. Its volatile organic compounds (VOCs) inhibited N. rosae hyphal growth by 70 ± 3.81%, with (1S)-(-)-α-pinene identified as the key antifungal component (EC50 = 0.018 mL·L−1). Fumigation with 6× EC50 α-pinene reduced fruit rot by 97.52% in a concentration-dependent manner. SEM observations showed that α-pinene caused severe hyphal damage and suppressed pathogen colonization on fruit surfaces. Transcriptomic analysis further indicated that α-pinene treatment was associated with redox regulation, glutathione metabolism, phenylpropanoid metabolism, and carbon-metabolism-related responses in strawberry fruit. These findings suggest that α-pinene controls postharvest anthracnose through direct antifungal activity on fungal hyphae together with host-associated physiological regulation, highlighting its potential as a sustainable postharvest biocontrol candidate.