Rhizosphere bacterial community composition was significantly affected by continuous cropping but not by sesame genotype

Abstract

Imbalanced soil bacterial community is thought to be a crucial factor for continuous cropping obstacle. Through analyzing bacterial community by Illumina MiSeq technology, this study bacterial community diversity and richness, like Sobs, Ace and PD decreased with duration of continuous cropping (CC). Alpha diversity and principal coordinate analysis (PCoA) revealed that soil bacterial diversity and community structure were significantly affected by CC but not by genotype. With increasing years of CC, rhizosphere bacterial community changed gradually, rather than skipping or irregular change. Almost all significantly changed genera under CC belong to Chloroflexi, Actinobacteria, Proteobacteria, Acidobacteria and Firmicutes, which indicated the vital roles of these five phyla in CC. With extension of CC, the abundance of Variibacter, Candidatus_Solibacter decreased, while Sinomonas and Burkholderia-Paraburkholderia increased in the genus level. Additionally, the transport and metabolism of amino acid and carbohydrate were increased or maintained under CC, but vesicular transport and cell motility reduced. These data provided novel insights into the changes of bacterial community under short duration of CC, and will contribute to understanding of continuous cropping.