Characterizing Rhizoctonia oryzae Isolates from Diseased Rice Sheath and Paddy Soils in Vietnam and Japan based on Fatty Acid Analysis

Abstract

New isolates of Rhizoctonia oryzae were obtained from contaminated paddy soils in northern Vietnam. These isolates showed different culture types compared to standard isolates from diseased rice sheath. Fatty acid composition of two culture types of Rhizoctonia oryzae, i. e., new and standard isolates from diseased rice sheath and contaminated paddy soils, was analyzed by gas-liquid chromatography. The major fatty acids identified were palmitic, palmitoleic, oleic and linoleic acids, which constituted 96-97% of all cellular fatty acids identified and each fatty acid composition showed differences in quantity. Principal component analysis and cluster analysis revealed that these two isolates were able to divide into different types based on fatty acids composition. ‘The results suggest that our new isolates could indicate one of the mutations of R. oryzae isolates.