Analysis of whole cellular fatty acids and anastomosis relationships of binucleate Rhizoctonia spp. associated with Ceratobasidium cornigerum

Abstract  Previous research has demonstrated that whole cellular fatty acids analysis is a useful tool for identifying and establishing taxonomic relationships between anastomosis groups (AGs) and related Rhizoctonia isolates. In this experiment, the composition of fatty acid of 28 isolates of teleomorph genus Ceratobasidium cornigerum, consisting of binucleate Rhizoctonia, AG-A, AG-B(o), AG-C, AG-P, and AG-Q, was evaluated using gas chromatography. Eleven fatty acids identified, i.e., myristic, pentadecanoic, palmitic, 2-hydroxypalmitic, palmitoleic, heptadecanoic, 9-heptadecenoic, stearic, oleic, linoleic, and linolenic acids, were present in isolates of AG-A, AG-B(o), AG-C, AG-P, and AG-Q. The major fatty acids, palmitic, oleic, and linoleic acids, were common in all isolates, constituting 87.1% to 94.7% of the whole cellular fatty acids identified. Isolates within the same AG were closely clustered, whereas isolates from different AGs were clearly and distinctly clustered based on average linkage cluster analysis of whole cellular fatty acids. Principal-component analysis generated from all fatty acids also confirmed the divergent separation of the 5 AGs of binucleate Rhizoctonia.