Abstract:The rhizosphere soil bacterial diversity and community structures of two halophytes, Lycium ruthenicum and Kalidium caspicum, typically distributed in the arid land of Northwest China, were studied using the high-throughput sequencing technique. The aim of this study was to reveal the rhizosphere soil bacterial community structures and the differences between rhizosphere and bulk soil bacterial communities, to provide the basis for further investigation of the relationship between rhizosphere soil microbes and salt tolerance of halophytes. The results show that, the rhizosphere soil bacterial diversity was higher than that of bulk soil, and the rhizosphere soil bacterial diversity of L. ruthenicum was higher than that of K. caspicum. The bacterial community was different in composition and abundance between the rhizosphere and bulk soils. A total of 21 phyla and 289 genera, and 22 phyla and 304 genera were detected in the rhizosphere soil of L. ruthenicum and K. caspicum, respectively. The bulk soils of L. ruthenicum and K. caspicum included 28 phyla and 285 genera, and 24 phyla and 336 genera, respectively. Proteobacteria and Firmicutes were the most abundant phyla in both rhizosphere and bulk soil bacterial communities. The abundance of Bacteroidetes, Actinobacteria, Cyanobacteria, and Planctomycetes in rhizosphere soil was significantly higher than in bulk soil, while the abundance of Firmicutes was lower than in bulk soil. The number of dominant genera in the rhizosphere soils was higher than that in the bulk soils. There were 10 and 9 dominant genera in the rhizosphere soils of L. ruthenicum and K. caspicum respectively, but only 4 genera in bulk soils. Pseudomonas was the only dominant genus in both rhizosphere and bulk soils. Pseudomonas and Halomonas were the common dominant genera of the two plants' rhizosphere soil bacterial communities. Unifrac and cluster analysis showed that the similarity between rhizosphere soil bacterial communities of the two plants was greater than that between the rhizosphere and bulk soil bacterial communities. There was a positive correlation between rhizosphere soil bacterial diversity and soil total organic carbon (TOC), soil organic matter (SOM), and total nitrogen (TON) contents, and a negative relationship with pH and EC. EC, pH, TOC, and TON were the main influencing factors of both bulk and rhizosphere soil bacterial communities.