ISOLATION AND SELECTION OF ENDOGENOUS BACTERIA THAT ARE ANTAGONISTIC TO THE FUNGUS EXOBASIDIUM VEXANS CAUSING TEA LEAF BLISTER DISEASE

Abstract

Tea leaf blister disease caused by the fungus Exobasidium vexans damages young leaves and young buds on tea plants. The disease has a rapid spread, seriously affecting the yield and quality of tea buds. The objective of the study was to selectively isolate endogenous bacteria that are antagonistic to the pathogenic fungus Exobasidium vexans as a biological control agent. From 14 isolates of endophytic bacteria in samples of shoots, stems and roots of tea plants, 3 strains of endophytic bacteria Y2.2, Y2.5 and Y2.7 were selected with high antagonistic activity against the pathogenic fungus Exobasidium vexans. (optimal ring diameter from 0.7 to 1.9 cm) under invitro conditions. After 3 days of co-culture of these strains with Exobasidium, the mycelium was broken and gradually failed to grow. The results of sequencing 16S rDNA fragments of two strains of bacteria Y2.2 and Y2.5 showed that strain Y2.2 had 100% similarity with Bacillus subtilis SMY, NCIB 3610 was 100% and strain Y2.5 had a similarity rate. 100% similarity to Burkholderia cepacia.