Comparative Analysis of the Rhizospheric Bacterial Communities of Flue-Cured Tobacco Affected by Granville Wilt

Abstract

Ralstonia solanacearum is a yield-limiting disease in flue-cured tobacco production in the Southeast United States and other major producing countries worldwide. Studies determining the association between the rhizospheric bacterial community composition, R. solanacearum distribution in the field, and soil physicochemical properties have not been conducted. In this study, the 16S rRNA gene of 144 rhizosphere samples, collected from three different fields (A, B, and C) in North Carolina, were sequenced using Illumina MiSeq v3 chemistry to (i) compare the rhizospheric bacterial community of healthy and diseased plants inside and outside “hot-spots”; (ii) identify potential bacterial indicators for Granville wilt suppression; and (iii) examine edaphic factors associated with rhizospheric bacterial composition and disease distribution in flue-cured tobacco fields. The phylum Proteobacteria was the most abundant in all fields and sampled locations within fields. Eighteen genera, including Bacillus and Pantoea, which are known antagonists of R. solanacearum, were consistently found in the rhizosphere samples from healthy plants in only one of the fields. Organic matter, Mn, and Ca contents were descriptive of the rhizosphere community structure found in healthy samples. In conclusion, the results obtained from the present study suggest that disease outcome and distribution could be associated with variation on community composition driven by edaphic factors and the presence of an antagonist. This study provides evidence of naturally occurring antagonists that could be exploited in novel management strategies for R. solanacearum suppression in modern flue-cured production systems. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .