Isolation and Identification of Bacillus altitudinis ZJ 186 from Marine Soil Samples and its Antifungal Activity Against Magnaporthe oryzae

A strain Bacillus altitudinis ZJ 186 capable of producing antifungal compounds to inhibit the growth of seven tested physiological races of Magnaporthe oryzae was isolated from marine soil samples and characterized by biochemical and physiological identification as well as 16S rDNA sequence analysis. The filtrate from the culture broth of strain ZJ 186 showed strong growth inhibition against all tested physiological races of Magnaporthe oryzae indicating that suppression of the growth of the fungi was due to the presence of antifungal compounds in the ferment broth. Results showed that the filtrate exhibited antifungal activity at 20 h after inoculation and became significant correlated with the cell growth over 96 h cell growth period (p<0.01). Antifungal activity was relatively stable when the filtrate was exposed to conditions in the pH range 1-8, but was sensitive to alkalinity conditions. Moreover, the antifungal components lost partial activity when the temperature increased, but kept a quite thermally stable with approximately 40% of the activity of the culture filtrate being held at 60, 80 and 100°C for 30 min, respectively. It’s the first report of bacterium Bacillus altitudinis showing antifungal capability against Magnaporthe oryzae.