Spinosyn α4, a potential insecticide against Plutella xylostella from Saccharopolyspora sp. AN150100

Chinese cabbage (Brassica rapa subsp. pekinensis) and cabbage (Brassica oleracea var. alba) are global staples. The diamondback moth (Plutella xylostella), a serious pest that causes billions of dollars in economic loss globally. Climate change has increased its survival and reproductive potential, boosting its range and population density. The development of resistance to commercial insecticides, such as spinetoram and spinosad, make pest management more difficult. Biopesticides are promising alternatives owing to their environmental compatibility and target specificity. This study aimed to identify novel bio-insecticidal agents from microbial sources against diamondback moth (DBM). In total, 500 actinomyces were isolated from soil samples collected in South Korea. Among them, Saccharopolyspora sp. AN150100 showed 80-90 % insecticidal activity against P. xylostella larvae, even when the culture broth was diluted 20-fold. Notably, spinosyn α4, a compound produced by this strain, exhibited 70 % larvicidal activity at a concentration of 0.025 mg/L, which was comparable to the efficacy of spinetoram and spinosad. Spinosyn biosynthesis gene clusters (PKS: spnA,- E and other additional spnF - M) were compared from the genomes of all Saccharopolyspora genus belonging members through antiSMASH. It is the first time to report insecticidal activity of spinosyn α4 against DBM. These findings suggest that spinosyn α4 from Saccharopolyspora sp. AN150100 could serve as an effective and eco-friendly alternative for controlling P. xylostella.