Seagrass-microbial interactions in the rhizosphere

Abstract:

[Objective] This research aims to investigate the response of rhizosphere microbial community after seagrass transplantation to high temperature treated seagrass sediment in Sanya Bay.[Methods] The environmental parameters including pH, dissolved oxygen, phosphate, nitrate, nitrite and ammonium were measured. High-throughput sequencing and real-time quantitative PCR of the 16S rRNA gene were used to analyze the diversity, structure and abundance of microbial communities in the rhizosphere of seagrass Thalassia hemperichii.[Results] The concentration of seawater nutrients (phosphate, nitrate, nitrite, ammonium) and pH were significantly higher in high temperature treatment group after 35 days. The abundance of 16S rRNA gene increased firstly and then reduced with the time. In addition, Firmutes (32.4%), Fusobacteria (27.21%) and Proteobacteria (22.92%) were the dominant phyla in rhizosphere in high temperature treatment group at the beginning of incubation period. But Firmutes and Fusobacteria were then decreased and replaced by Cyanobacteria and Actinobacteria over time. Proteobacteria (51.1%) dominated the rhizosphere microbial communities in the final phase. Moreover, Desulfobacteraceae belonging to sulfate-reducing bacteria and Helicobacteraceae affiliated with sulfate-oxidizing bacteria increased over time.[Conclusion] Colonization of seagrass would improve the microbial diversity of high temperature treated sediment, shape and change the microbial communities in rhizosphere.