Effects of Bacillus velezensis HN-Q-8 on the microbial community structure and physicochemical properties of potato rhizosphere soil

Abstract:

[Background] Bacillus velezensis can promote the growth of crops and inhibit the growth of a variety of pathogens. However, the knowledge is limited regarding the effects of B. velezensis on the rhizosphere microecology of crops. [Objective] The effects of B. velezensis HN-Q-8 on the microbial community structure and physical and chemical properties of potato rhizosphere soil were studied in order to provide a theoretical basis for the application of Bacillus in potato production. [Methods] Potato rhizosphere soil samples were inoculated with the fermentation liquid with bacterial cells (FLBS), fermentation liquid without bacterial cells (FL), and bacterial cell suspension (BCS) of strain HN-Q-8, respectively. The changes of microbial diversity and community structure of potato rhizosphere soil under different treatment conditions were determined by high-throughput sequencing. Furthermore, the changes in physicochemical properties of potato rhizosphere soil were determined. [Results] Strain HN-Q-8 had no significant effect on the microbial diversity but affected the microbial community structure in potato rhizosphere soil. Compared with the control, each treatment significantly increased the relative abundance of beneficial bacteria, such as Lysobacter, Bacillus, and Mortierella, in potato rhizosphere soil, which improved the microbial community structure of potato rhizosphere soil. In addition, strain HN-Q-8 enhanced the activities of urease, phosphatase, and catalase and significantly increased the content of available nitrogen, available phosphorus, and available potassium in potato rhizosphere soil. [Conclusion] B. velezensis HN-Q-8 regulates the microbial community structure and increases the relative abundance of beneficial microorganisms in potato rhizosphere soil. Furthermore, it enhances the enzyme activity and fertility of rhizosphere soil, shaping a favorable soil environment for potato growth and development of resistance against pathogen infection.