Evaluation of antibacterial activity of actinomyces isolates on Colletotrichum sp. causing anthracnose disease on welsh onion (Allium fistulosum L.)

Abstract

The objective of this research was to examinate the actinomycetes able to antagonize with Colletotrichum sp. fungus causing anthracnose disease on Welsh onion. The antagonistic ability against Colletotrichum sp. fungus of 20 actinomycetes isolates were determined with 5 replications. The results found that 5 isolates MX12-ST, BT42-VL, MX5-ST, TM4-ĐT and CL3-TG could reduce mycelia growth of fungus with radiuses of inhibition zones reaches 10.75 mm, 7.75 mm, 5.75 mm, 5.50 mm, 5.25 mm respectively and antagonistic efficacy 80.20%, 64.07%, 56.95%, 59.20%, 54.85% respectively at 9 days after inoculation. The β-glucan degradation potential of 5 actinomycetes (MX12-ST, BT42-VL, MX5-ST, TM4-ĐT, CL3-TG) were examined with 5 replications. The results showed that 2 isolates MX12-ST and BT42-VL have expressed the β-glucanlytic activity, with the β-glucan lyses halo radius of 11.1 mm và 11.7 mm at 14 days after testing. Beside, chitinase activity of these actinomycetes isolates was performed on chitin medium with 5 replications. The result indicated that, 2 isolates MX12-ST and BT42-VL showed the highest chitinolytic activity with the chitin lyse halo radius of 19.9 mm and 18.7 mm at 7 days after examination.