Antimicrobial activity and comparative metabolomic analysis of Priestia megaterium strains derived from potato and dendrobium

Abstract

AbstractThe growth of endophytic bacteria is influenced by the host plants and their secondary metabolites and activities. In this study,P. megateriumP-NA14 andP. megateriumD-HT207 were isolated from potato tuber and dendrobium stem respectively. They were both identified asPriestia megaterium. The antimicrobial activities and metabolites of both strains were explored. For antimicrobial activities, results showed thatP. megateriumP-NA14 exhibited a stronger inhibition effect on the pathogen of dendrobium, whileP. megateriumD-HT207 exhibited a stronger inhibition effect on the pathogen of potato. The supernatant ofP. megateriumP-NA14 showed an inhibition effect only onStaphylococcus aureus, while the sediment ofP. megateriumD-HT207 showed an inhibition effect only onEscherichia coli. For metabolomic analysis, the content ofL-phenylalanine inP. megateriumP-NA14 was higher than that ofP. megateriumD-HT207, and several key downstream metabolites ofL-phenylalanine were associated with inhibition ofS. aureusincluding tyrosine, capsaicin, etc. Therefore, we speculated that the different antimicrobial activities betweenP. megateriumP-NA14 andP. megateriumD-HT207 were possibly related to the content ofL-phenylalanine and its metabolites. This study preliminarily explored why the same strains isolated from different hosts exhibit different activities from the perspective of metabolomics.