[In vitro screening and identification of plant growth-promoting rhizobacteria against pathogen causing Astragalus root rot].

The antagonistic effect of Bacillus spp. against Fusarium solani was evaluated by living body dual culture and Oxford cup method. The plant growth promoting properties of those strains that had obvious and stable antifungal activity were then tested. The results showed that the living body and bacteria-free fermentation filtrate of strain G10 both had obvious and stable antifungal effect to F. solani. Besides, the strain possessed such growth promoting properties as phosphate solubilization, nitrogen fixation, and production of IAA, amylase and HCN. Strain G10 was classified and identified as B. subtilis by a combination of morphological, physiological and biochemical tests, 16 SrDNA gene sequence analysis and the BBL CrystalTM bacteria identification. In conclusion, B. subtilis G10 has the basic characteristics of multifunctional strains and could be one of the microbiological resources for developing special bio-control agent against Astragalus root rot.