BIOLOGICAL CONTROL OF CORYNESPORA CASSIICOLA CAUSING CORYNESPORA LEAF FALL DISEASE (CLF) ON RUBBER TREE BY BACILLUS THURINGIENSIS (T3)
Bacillus thuringiensis (T3) isolated from foliage and sapwood of Hevea brasiliensis is demonstrated to have biological control potential against CLF disease caused by Corynespora cassiicola. Pathogenicity of C. cassiicola is caused by the toxin, cassiicolin. This toxin is encoded by cassiicolin gene (cas). Screening of cas genes was conducted with twenty C. cassiicola isolates from Vietnam e by using PCR method. Two isolates were classified as cas2 and the remaining as cas0. C. cassiicola isolate containing cas2 gene (CoryQN01) was inoculated on detached rubber leaves with and without the treatment of B. thuringiensis (T3) bacterial isolate at various time intervals. The results indicated that cassiicolin gene expression was down-regulated under treatment with B. thuringiensis (T3).
Keywords: antifungal ability, Corynespora cassiicola, cas gene, Bacillus thuringiensis