[Diversity of microbial community structure in the spermosphere of saline-alkali soil in shandong area].

Objective: Three soil types in different salt contents were taken as the experiment objectives. We evaluated the effect of various saline alkali soil types on diversity of bacterial community structure in spermosphere soil during water absorption and germination of peanut seeds.

Methods: The V3-V4 region of 16S ribosomal RNA genes was amplified using PCR, and the PCR products were then analyzed using Illumina high-throughput sequencing technology.

Results: (1) The diversity of soil bacterial community in saline alkali soil was higher than that in non-saline alkali soil. Especially, the highest diversity was in spermosphere soil from Qingtuo. (2) The microflora structures in different soils were distinct at the class level. Soil bacteria in four samples were classified into six classes, including Proteobacteria, Actinobacteria, Actinobacteria, Bacteroidetes, Acidobacteria and Firmicutes. Proteobacteria and Actinobacteria groups were dominant in colonies. The analysis of whole samples colony structure showed that the difference of type and abundance at phylum and genus level during different adsorption time was most significant (P<0.05). (3) The analysis of beta diversity and phylogenetic distances of constructed phylogenetic trees revealed that the sequenced clones fell into two major groups within the domain bacteria.

Conclusion: The diversity of bacteria community compositions in the high salt content soil was higher. There were obvious differences in microbial community structure of different soil types at class level, primarily in the Proteobacteria and Actinobacteria. The type and abundance of microbial colonies at both phylum and genus levels were affected by the seed germination time. However, there was no influence on the genetic distance between the samples from the same soil type.