Isolation, Identification and Antifungal Activities of Streptomyces aureoverticillatus HN6

Abstract

Banana Fusarium wilt caused by Fusarium oxysporum f. sp. cubense race 4 (FOC4) is destroying numerous banana plantations in southern China. In order to select an effective biocontrol agent for this devastating disease, eighty nine actinomycete isolates were collected from soil samples in the Botanical Garden of Chinese Academy of Tropical Agricultural Sciences in the tropical Hainan Province, China. These isolates were evaluated for their antagonistic activity against FOC4. Our results showed that eight isolates exhibited strong anti-FOC4 activity. One of the isolates, HN6, resulted in an inhibition zone of 35 mm in diameter in the antagonistic test. The mycelia of HN6 were extracted with methanol, and the extract was tested against eight indicator pathogens by the mycelium growth rate method. The HN6 extract demonstrated broad-spectrum antifungal activity, with an EC50 less than 0.08 mg/ml. Based on the morphological, biochemical, physiological and cultural characteristics and the 16S rRNA gene sequence, the HN6 isolate was identified as Streptomyces aureoverticillatus. HN6 isolate can be potentially developed into a biocontrol agent for banana Fusarium wilt and other plant diseases.