Functional characterization and mechanistic basis of antifungal and plant growth-promoting traits of Streptomyces sp. LZZY-S40

, it increased root length by 88.3%, shoot length by 37.9%, and fresh weight by 32.1%. Consistent with these phenotypic effects, the strain tested positive for multiple well-established PGP traits-including indole-3-acetic acid (IAA) production, siderophore secretion, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, and nitrogenase-mediated nitrogen fixation-providing mechanistic support for its growth-enhancing capacity. Collectively, these findings demonstrate that strain LZZY-S40 exhibits robust antifungal activity against a broad spectrum of plant-pathogenic fungi and promotes plant growth significantly. Mechanistic investigations provided preliminary insights into the strain's antifungal and plant growth-promoting traits, contributing to a better understanding of its potential as a dual-action biocontrol agent.