생물방제균 Bfacillus subtilis YB-70의 외부 Urease 유전자 도입과 길항력 증강

To genetically breed powerful multifunctional antagonistic bacteria, the urease gene of alkalophilic Bacillus pasteurii was transferred into Bacillus subtilis YB-70 which had been selected as a powerful biocontrol agent against root-rotting fungus Fusarium solani. Urease gene was inserted into the HindIII site of pGB215-110 and designated pGU266. The plasmid pGU266 containing urease gene was introduced into the B. subtilis YB-70 by alkali cation transformation system and the urease gene was very stably expressed in the transformant of B. subtilis YB-70(pGU266). The optimal conditions for the transfomation were also evaluated. From the in vitro antibiosis tests against F. solani, the antifungal activity of B. subtilis YB-70 containing urease gene was much efficient than that of the non-transformed strain. Genetic improvement of B. subtilis YB-70 by transfer of urease gene for the efficient control seemed to be responsible for enhanced plant growth and biocontrol efficacy by combining its astibiotic action and ammonia producing ability.