Composition and functional comparison of vetiver root endophytic microbiota originating from different geographic locations that show antagonistic activity towards Fusarium graminearum

Given the current trend towards reducing the use of chemical controls in agriculture, microbial resources such as plant endophytes are being intensively investigated for traits that are conducive to plant protection. Among the various important target pathogens, Fusarium graminearum is a fungal pathogen of cereal crops that is responsible for severe yield losses and mycotoxin contamination in grains. In the present study, we investigated the bacterial endophytic communities from vetiver (Chrysopogon zizanioides (L.) Roberty) roots originating from 5 different geographic locations across Europe and Africa. This study relies on a global 16S metabarcoding approach and the isolation/functional characterization of bacterial isolates. The results we obtained showed that geographical location is a factor that influences the composition and relative abundance of root endophyte communities in vetiver. Three hundred eighty-one bacterial endophytes were isolated and assessed for their in vitro antagonistic activities towards F. graminearum mycelium growth. In total, 46 % of the isolates showed at least 50 % inhibitory activity against F. graminearum. The taxonomic identification of the bioactive isolates revealed that the composition of these functional culturable endophytic communities was influenced by the geographic origins of the roots. The selected communities consisted of 15 genera. Some endophytes in Bacillus, Janthinobacterium, Kosakonia, Microbacterium, Pseudomonas, and Serratia showed strong growth inhibition activity (≥70 %) against F. graminearum and could be candidates for further development as biocontrol agents.