Abstract:

Bacillus altitudinis LZP02 is a rice rhizosphere growth-promoting bacterium, which can colonize rice rhizosphere to form biofilm. In order to study the formation of B. altitudinis LZP02 biofilm under different culture conditions, the formation of B. altitudinis LZP02 biofilm was observed by 96-well microplate method, and it was quantified by crystal violet staining. The results showed that B. altitudinis LZP02 formed a stable biofilm structure on surface of the culture medium and had good biofilm formation ability.The optimum temperature of B. altitudinis LZP02 for biofilm formation was 30 ℃, but only a few biofilms were formed at 25 ℃, which indicated that low temperature reduced the biofilm formation ability of B. altitudinis LZP02.Biofilm could be formed at pH 4-10, and the ability of biofilm formation was strongest at pH 7.0. Ca²⁺ had no obvious effect on the formation of B. altitudinis LZP02 biofilm. Fe²⁺, Fe³⁺, Mg²⁺, K⁺, Na⁺, Zn²⁺ and Cu²⁺ inhibited the formation of B. altitudinis LZP02 biofilm, while Mn²⁺ promoted the formation of B. altitudinis LZP02 biofilm.The research results provided an important reference for the further development and utilization of B. altitudinis LZP02, and also provided a realistic basis for further exploring the biofilm formation mechanism of B. altitudinis LZP02.

Key words: Bacillus altitudinis LZP02, biofilm, metal ions, rhizosphere growth-promoting bacterium of rice