The antibacterial T6SS of Agrobacterium tumefacien promotes disease occurrence and influences crown gall microbiota composition

A. tumefaciens T6SS is not essential for pathogenesis under direct inoculation but it remains unknown whether T6SS influences natural disease incidence and microbial community of crown galls. To address these two key questions, we established a soil inoculation method on wounded tomato seedlings that mimics natural infections and performed 16S rRNA gene amplicon sequencing. By comparing the A. tumefaciens C58 wild-type strain with two T6SS mutants, we demonstrated that the T6SS influences disease occurrence and microbiota composition within crown galls.