Isolation and
selection of Actinomycetes strains against Phytophthora palmivora from Durian soil
in Dak Lak, Vietnam
Nha Nguyen Thi Minh, Ngo Le Van and Anh Đinh Thi Lan
Res. J. Biotech.; Vol. 20(5); 168-174;
doi: https://doi.org/10.25303/205rjbt1680174; (2025)
Abstract
The present study focuses on selecting actinomycetes strains from Durian garden
soil in Dak Lak province with strong antagonistic activity against the fungus Phytophthora
palmivora (P. palmivora), which causes leaf blight and fruit rot disease in durian
trees. A total of 117 actinomycetes strains were isolated from 15 soil samples,
among which strain NMN64 exhibiting strong antifungal activity, was further investigated
under suitable fermentation conditions. After 10 days of fermentation in PM43 medium
(15 liters) at 35°C and pH 6.3, NMN64 showed strong antagonistic activity with 68%
efficiency.
Initial isolation of the antifungal compound using Sephadex LH-20 gel filtration
chromatography and HPLC analysis revealed that sub-fraction 3.2 was the most active
one, achieving an efficiency of 63%. This result suggests that potential antifungal
compound(s) against P. palmivora could be produced from strain NMN64, which could
be used for controlling leaf blight and fruit rot in durian trees.
