Diversity analysis of Fusarium oxysporum f. sp. gladioli isolates using fatty acid methyl ester (FAME) profiling

Two geographically different isolates of Fusarium oxysporum f. sp. gladioli, namely Isolate-1 collected as infected gladiolus corms from research farm of IARI, New Delhi, and Isolate-2 from infected corms at research farm of GBPUA&T, Pantnagar, Uttarakhand were selected for the experiment. The fatty acid methyl ester profile was determined by initially converting the cellular lipids to their corresponding Fatty Acid Methyl Esters (FAMEs). Both the Fog isolates were quite distinct with respect to the fatty acids profiles and also percentage compositions of different fractions, which ranged from less than 1 to over 46% of the total identified fatty acids content. The most common and abundant fatty acids in the two Fusarium isolates were palmitic acid (C16: 0), margaric acid (C17: 0), stearic acid (C18: 0), and arachidic acid (C20: 0) as unsaturated and palmitoleic acid (C16: 1 n_7), cis-10heptadecenoic acid (C17: 1 n_8), oleic acid (C18: 1 n_9) and linoleic acid (C18: 2 n_6), which accounted for 94.45 and 98.35% of the fatty acid profiles in IARI and Pantnagar F. oxysporum f. sp. gladioli isolates, respectively suggesting that they are distinct and also differ in pathogenecity. This is the first ever attempt to characterize Fusarium oxysporum f. sp. gladioli isolates using FAME in the country.