Bacterial community structure and diversity of rhizosphere soil and stem of healthy and bacterial wilt tobacco plants

Abstract:

[Objective] To understand the bacterial community structure and diversity of healthy and bacterial wilt tobacco plants in rhizosphere soil, diseased stem tissue, symptomatic-asymptomatic junction stem tissue, and non-infected stem tissue. [Methods] The V3-V4 region of the bacterial 16S rRNA gene in soil and stem tissue was amplified, and the amplified fragments were sequenced using Illumina MiSeq high-throughput sequencing technology. [Results] Proteobacteria were the dominant phylum in all samples. Bacteroidetes and Acidobacteria were the dominant phyla in all rhizosphere soil. Cyanobacteria was the dominant phylum in non-infected stem tissue; and Cyanobacteria and Firmicutes were dominant in diseased stem tissue and symptomatic-asymptomatic junction stemtissue. The dominant genera in all rhizosphere soil were Ralstonia, Pseudomonas and Sphingomonas. The dominant genera of tobacco stem were Ralstonia and Pseudomonas. [Conclusion] Compared with non-infected tobacco plants, the richness and diversity of bacterial community in rhizosphere soil and stem tissue of bacterial wilt tobacco plants were generally greater. Bacterial wilt is a typical soil-borne disease, although the pathogen Ralstonia solanacearum can spread and expand in the vascular bundles, it mainly distributes in the soil. Therefore, the control of bacterial wilt should not be limited to the tobacco plant itself, but targeting the pathogen in field soil may strengthen the control efforts.