Impact of seed soaked by Bacillus on endophytic bacterial community structure of rice

Endophytic bacteria in plant are important components of plant micro-ecosystems. The endophytic bacterial community structure of rice is an important biological indicator for the plant to evaluate the internal environment being health and stabilization or not. Bacillus strains are important bio-control microorganisms. In order to reveal the impact of the endophytic bacterial community structure of rice because of seeds dipped in fermentation broth of 3 Bacillus strains, the illumina MiSeq technology was used to detect 16 S rRNA gene of rice endophytic bacteria. The micro-ecological regulating effect on endophytic bacterial community of rice seeds treated with Bacillus suspension was analyzed. The experimental results showed that the community richness index and evenness index of endophytic bacterial community structure of rice root and stem were promoted, the richness index and evenness index of rice leaf was reduced, and the community diversity of endophytic bacterial community structure of rice root was increased significantly after rice seeds dipped in Bacillus suspension. Among all experimental treatments, the same preponderant phylums of rice root and stem were Proteobacteria, Firmicutes and Bacteroidetes. In addition, Proteobacteria and Bacillus were the same preponderant phylum and genus of rice leaf, respectively. After the rice seeds dipped in fermentation broth of 3 Bacillus strains, the relative abundance of Proteobacteria and Bacillus of rice leaf were promoted obviously. In addition, the Operational Taxonomic Units(OTU) number of endophytic bacteria in rice root and stem tissue was increased evidently and the OTU number in rice leaf was not changed significantly compared to the water control. The endophytic bacterial abundance of rice root and stem involving in metabolic pathways was reduced and that the abundance of rice leaf was increased significantly. Therefore, the measure that rice seeds were dipped in fermentation broth of Bacillus strains could change evidently the endophytic bacterial community structure of rice root, stem and leaf, and improve the microecological environment of rice growth.