芽胞杆菌浸种对水稻内生细菌群落结构的影响

水稻内生细菌群落是反映植株内环境是否健康稳定的重要生物学指标,芽胞杆菌是防治水稻病害的重要生防微生物。为揭示芽胞杆菌浸种处理对水稻内生细菌群落结构的影响,采用Illumina MiSeq测序的方法对水稻内生细菌的16S rRNA基因进行测序,剖析了芽胞杆菌浸种处理对不同水稻组织内生细菌的微生态调控作用。结果表明,3种芽胞杆菌浸种处理可以提高水稻根和茎部内生细菌群落的丰富度和均匀度,降低叶部内生细菌群落的丰富度和均匀度,显著增加根部内生细菌群落多样性。变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)是水稻根部和茎部共有优势菌门,厚壁菌门和芽胞杆菌属(Bacillus)是叶部共有优势菌门和属。芽胞杆菌浸种处理显著提高了叶部内生厚壁菌门和芽胞杆菌属的相对丰度,增加了根系和茎部组织内生细菌的分类单元OTU(Operational Taxonomic Units)数量,对叶部组织影响不明显;降低了茎部和叶部中参与各种代谢通路的内生细菌丰度,显著增加了根部参与代谢通路的内生细菌丰度。因此,3种芽胞杆菌浸种处理可以显著改变水稻根部、茎部和叶部内生细菌群落结构,改善水稻生长的微生态环境。

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 16S 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.