Abstract:

【Objective】To clarify the differences in bacterial community structure and diversity in rhizosphere soil planted with Elymus sibiricus Linn.，Elymus canadensis L. and the first hybrid generation on sandy dark chestnut soil in Inner Mongolia. Also clarify the mechanisms of interaction between environmental factors and the bacterial community.【Methods】The Illumina MiSeq sequencing platform was used to perform high-throughput sequencing of the bacterial community 16S rRNA gene in rhizosphere soil planted with Elymus sibiricus Linn.，Elymus canadensis L.，and the first hybrid generation（Elymus sibiricus Linn. as male parent and Elymus canadensis L. as female parent）. Bioinformatics analysis was used to compare the structure and diversity of the bacterial community in the rhizosphere soil of the three plant species，as well as the correlation between bacterial composition and soil chemical indicators.【Results】Shannon-Wiener index，ACE index and Chao1 index of Elymus sibiricus Linn. rhizosphere soil bacterial community were the highest，while Simpson index of Elymus canadensis L. rhizosphere soil bacterial community was the highest. The common dominant phyla of the rhizosphere soil bacterial communities of the three plant species were Actinobacteria，Proteobacteria，Chloroflexi and Acidobacteria. The dominant phyla of the rhizosphere soil bacterial communities of Elymus sibiricus Linn. and the first hybrid generation was Bacteroidete. The common dominant genus of rhizosphere soil bacterial communities of the three plant species was Arthrobacter. The dominant genera of rhizosphere soil bacterial communities of Elymus sibiricus Linn.，Elymus canadensis L. and the first hybrid generation were Shewanella，Nocardioides and norank-f-JG30-KF-CM45，respectively. In the rhizosphere soil of the three plant species，the pH value of Elymus canadensis L. rhizosphere soil was the lowest，and the contents of available nitrogen，available phosphorus and organic matter in Elymus sibiricus Linn. rhizosphere soil were the highest. Soil organic matter with Pseudomonas，norank-f-norank-o-Subgroup-7 and Subgroup-10，available nitrogen with Mycobacterium，available phosphorus with norank-f-norank-o-SBR1031，norank-f-norank-o-Subgroup-7，Subgroup-10，norank-f-A4b were all significant positively correlated. Soil organic matter with norank-f-norank-o-Gaiellales，Gaiella and norank-f-Gemmatimonadacea，available phosphorus with norank-f-norank-o-Gaiellales，Gaiella and norank-f-Ilumatobacteraceae were both significantly negatively correlated.【Conclusion】The rhizosphere soil bacterial community structure of the first hybrid generation were similar with Elymus canadensis L.，but quite different with Elymus sibiricus Linn.. The diversity of soil bacterial community structure were affected by soil chemical indicators and plant species.

Key words: Elymus sibiricus Linn., Elymus canadensis L., First hybrid generation, Rhizosphere soil, Bacterial community structure, Diversity