Endophytic <i>Streptomyces griseorubens</i> MEPSL1 from sweetpotato promotes plant growth and enhances γ-tocopherol accumulation

Streptomyces species are widely distributed in soils and plant tissues and are valued for their ecological safety and diverse biological functions. Here, we describe a multifunctional endophytic actinomycete, <i>Streptomyces griseorubens</i> MEPSL1, isolated from sweetpotato. This strain exhibits multiple growth-promoting traits and significantly increases γ-tocopherol accumulation in sweetpotato leaves, accompanied by the induction of key biosynthetic genes. Our findings highlight the role of endophytic actinomycetes in improving both crop performance and nutritional quality and point to their potential use in sustainable biofortification strategies.