Abstract:[Background] Land salinization is serious in inland and plain areas of north China,and the role of microorganisms in the vegetation succession of extreme saline-alkali land has been seldom reported.[Objective] To study the relationship between soil conditions and microbial community in the salt marshes with five types of vegetation (S1:bare;S2:succulent;S3:carex;S4:grass;S5:weeds) on the Ordos plateau,and screen out salt-tolerant bacteria and the soil factors affecting salt-tolerant bacteria.[Methods] Illumina MiSeq high-throughput sequencing was performed to analyze the microbial community composition.[Results] The soil bacterial abundance and diversity in the Ordos salt marshes with 5 different types of vegetation ranked in the order of S3>S5>S4>S2>S1 and S3>S5>S2>S4>S1,respectively.Proteobacteria was the most abundant phylum in the soil bacteria of the 5 vegetation types,and its relative abundance first increased and then decreased with the succession of the 4 salt marshes,which was contrary to the trend of Deinococcus-Thermus.Soil clay particle had a significantly positive correlation with Gemmatimonadetes,and its correlation with Firmicutes increased gradually with the increase in soil particle size.The soil chemical properties showing high correlations with bacterial community were in the order of AK>TP>SOC>TN>AN>AP>pH.[Conclusion] Proteobacteria was the most abundant bacterial phylum in Ordos salt marshes experiencing vegetation succession,and Actinomycetes,Alphaproteobacteria,and Blastomonas were the classes with stronger salt tolerance.The diversity and abundance of bacteria in S3 were the highest,and the adaptability of bacterial community varied regarding the soil particle size in salt-alkali areas.AK was the most significant soil factor affecting the bacterial community structure in the salt marshes of Ordos platform.
