Isolation, Identification And Application Of Bacteria For Biocontrol Of Sheath Blight

Banded leaf and sheath blight(BLSB) reduced the yield of maize greatly every year,which was the major disease of maize. In our study,we focused on defending BLSB using biocontrol bacteria. Thus, 277 respective strains of bacteria were isolated from different issues and rhizosphere soil of corn, wheat, canola and other plant, and 73 of 277 strains were resistant to Rhizoctonia solani by dilution culturing method, so the proportion of resistant strains was 26.35%. 56 strains which had better resistance to BLSB were selected for identification by 16 s r DNA gene, and 54 of the 56 strains were belong to Bacillus genus.Comprehensive antibacterial substances inhibitory effect and thermal stability of bacterial fermentation liquid, canola endogenous 330-2 was chosen for depth study. After the 16 s r DNA molecular identification and biolog detection, the strain 330-2 was identified as Bacillus subtilis. Bacillus subtilis 330-2 had a good resistance to BLSB and Botrytis cinerea. Even though the culture filtrate of 330-2 were treated at different temperatures, high temperature treatment had no significant effect on antimicrobial substance, and the antimicrobial substance had high thermal stability. After protease treatment, the inhibitory effect of 330-2 fermentation filtrate had no significant effect on Rhizoctonia solani and mycelial growth rat, indicating that the antimicrobial substance is not, or not entirely protein.Bacillus subtilis 330-2 had growth-promoting effect on corn and tobacco. After the strain 330-2 became resistant to Rifampin, we detected the colonization of Rifampin marked strain 330-2-Rif in maize. The strain 330-2-Rif had a good colonization ability in the leaf of maize. we found some references to improve fermentation condition in order to increase the number of strain 330-2, finally we successfully produced biological seed coating agent and some important indicator of 330-2 seed coating agent were tested.