Bacterial Diversity among Halophytes: Diversity of Bacterial Microbiome in Rhizosphere and Root Endosphere of Two Halophytes: Glaux maritima and Salicornia europaea

Root-associated microbial community structures are very important in the adaptation of halophytes in coastal ecosystems. However, few reports have described bacterial communities related to halophytes, and the distribution patterns of these bacteria in different plants have been rarely compared. In this report, we mainly studied the diversity and community structure of rhizosphere (Rh) and root endosphere (En) bacteria related to two kinds of halophytes, Glaux maritima and Salicornia europaea. We collected Rh, root (R), and bulk (Bl) control soil samples, and sequenced the V3-V4 region of the bacterial 16S rRNA gene using the Illumina MiSeq platform to identify bacterial communities originating from different plant species. Among samples related to G. maritima, the bacterial richness and diversity in Rh were higher than those in R, but lower than those of the Bl. Meanwhile Bl, Rh and R from S. europaea had similar bacterial richness and diversity. The numbers of operational taxonomic units exclusive to the R, Rh and Bl were 181, 366, and 924 in G. maritima and 126, 416, and 596 in S. europaea, respectively, implying habitat-specific patterns in each halophyte. In total, 35 phyla and 566 genera were identified. The dominant phyla across all samples were Proteobacteria and Bacteroidetes. Actinobacteria in the R from G. maritima have extremely high abundance. The beneficial genera of bacteria were enriched in R and Rh from two halophytes. Rhizobium, Actinoplanes, and Marinomonas significantly enriched in G. maritima, while Sulfurimonas and Coleofasciculus exhibited relatively higher abundances in S. europaea. Principal coordinate analysis demonstrated significant differences in microbiota composition associated with plant species and sample types. These results strongly indicate that there were clear differences in bacterial community diversity and structure between G. maritima and S. europaea. This is the first report to characterize root microbiome of G. maritima and compare diversity and community structure of Rh and root En bacteria in between G. maritima and S. europaea.