Metabarcoding reveals response of rice rhizosphere bacterial community to rice bacterial leaf blight.

ABSTRACT

Rice bacterial leaf blight (BLB) is a major disease affecting cultivated rice and caused by the bacterium Xanthomonas oryzae pv. oryzae (Xoo). It is well established that rhizosphere microorganisms could help improve the adaptability of plants to biotic stresses. However, it is still unclear about the response mechanism of rice rhizosphere microbial community to BLB infection. Here, we used 16S rRNA gene amplicon sequencing to explore the effect of BLB on the rice rhizosphere microbial community. The results show that the alpha diversity index of the rice rhizosphere microbial community decreased significantly at the onset of BLB and then gradually recovered to normal levels. Beta diversity analysis indicated that BLB significantly affected community composition. In addition, there were significant differences in the taxonomic composition between healthy and diseased groups. For example, ceretain genera were more abundant in diseased rhizospheres, namely Streptomyces, Sphingomonas, and Flavobacterium, among others. In addition, the size and complexity of the rhizosphere co-occurrence network increased after disease onset compared to healthy groups. Also, hub microbe Rhizobiaceae and Gemmatimonadaceae were identified in the diseased rhizosphere co-occurrence network, and these hub microbes played an important role in maintaining network stability. In conclusion, our results provide important insights into the rhizosphere microbial community response to BLB and also provide important data and ideas in using rhizosphere microbes to control BLB.