Microbial Diversity in Tobacco Rhizosphere Soil at Different Growth Stages

Rhizosphere microorganisms are the main participants of material transformation and energy cycle in soil. To further explore its composition and variation, the tobacco rhizosphere soil were sequenced by Illumina MiSeq, the microbial community at different growth stages were analyzed and compared. The analysis of Alpha diversity showed that, the Chao1 index, Shannon index of bacteria and Chao1 index of fungi in rhizosphere soil were the highest in tobacco budding stage, while the peak of Shannon index of fungi appeared in tobacco material stage. Principal component analysis (PCA) further showed that at different growth stages, Proteobacteria was the dominant, followed by Actinobacteria, Acidobacteria and Gemmatimonadetes for bacterials; Ascomycota was the dominant, followed by Zygomycota and Basidiomycota for fungi. Under field conditions, the microbial abundance changed with the growth of tobacco, and the microbial diversity reached the peak at budding stage. The bacterial community and abundance between budding and mature stages was highly similar, while the bacterial community in vigorous growth stage is quite different. The similarity of fungal community in budding stage was very low, compared with the other stages; while in other stages was high. This study provides a theoretical basis for further understanding the relationship between tobacco rhizosphere soil microbial diversity and variation, tobacco growth and soil diseases.