| description |
The crown gall disease in grapevine is mediated by Agrobacterium vitis and results in tumorous growth. The tumor offers an ecological niche for the pathogen and eventually for other bacteria as well. We wanted to know if the crown gall disease affects the bacterial community of the grapevine plant. Using next generation sequencing of the V4 region of 16S rDNA amplicons we recorded the microbiota from galled and non-galled grapevine plants as well as of the soil at three seasons of the year. The root, trunk, one-year-old cane and the soil hosted distinct microbiota, which differed according to spring, summer, and autumn. However, the crown gall disease influenced the structure of the microbiota only in grapevine trunks. There the bacterial richness was higher and comprised for example exclusively the plant pathogens Xanthomonas sp., Sodalis sp., and an unknown Gammaproteobacterium. The seasons additionally affected the microbiota in the trunks with and without a crown gall differently. A. vitis, Pseudomonas sp. and Enterobacteriaceae sp. were the most abundant sequences in crown galls at each season. In contrast, in healthy trunks (=non-galled) the microbial composition changed from season to season. Altogether, twenty-two operational taxonomic units, representing bacterial species, were significantly enriched in crown galls and only three in healthy trunks. Our results support the idea that other bacteria than the pathogen A. vitis can adapt to the crown gall environment. How these profit from the new environment and if they influence crown gall development will be the subject of future work. |