Screening of Actinomyces ssp. for Antagonistic Activity against Rice Sheath Blight, Rhizoctonia solani Kuhn

Abstract

     In this study, 10 isolates of the rice sheath blight fungus (KV1, KV6, KV8, KV10-KV16) were isolated from 20 different diseased samples collected in Ha Noi, Hai Duong, Thai Binh, Ha Nam and Hung Yen provinces. They were characterized based on cultural, morphological and physiological properties. In addition, PCR-RFLP and rDNA-ITS sequence analyses were also used to identify these isolates. Inoculation of 10 isolates on four non-glutinous cultivars Xi23, Q5, Khang dan and, BC15 and 2 glutinous rice cultivars, TK90 and 87 showed that 100% infection rate was achieved and the most virulent isolate was KV13. In vitro screening of 80 Actinomycetes isolates for antagonistic capability against the KV13 showed that 10 isolates of Actinomycetes had strong antagonistic activity. Of these, the Actinomyces isolate L2.5 showed the highest antagonistic activity against the isolate KV13. This isolate can be used for further study to develop products for sheath blight control in rice.