Grouping of isolates in AG 2 of Rhizoctonia solani by total cellular fatty acid analysis

Abstract

Total-cellular fatty acid compositions of 34 isolates of Rhizoctonia solani belonging to intraspecific groups (ISGs) of anastomosis group (AG) 2, i.e., AG 2-1, AG 2-2 IIIB (mat rush), AG 2-2 IV (sugar beet), AG 2-2 LP (turfgrass), and AG 2-3 (soybean), were compared. The major fatty acids identified were palm/tic, stearic, and oleic acids. Principal component analysis based on the percentage composition of total cellular fatty acids revealed consistently low variability among isolates of a single ISG of AG 2. Average linkage cluster analysis showed that isolates obtained from turfgrass representing a newly proposed group, AG 2-2 LP, were differentiated from other AG 2 ISGs. Isolates of another newly proposed group AG 2-3, from diseased soybean were also closely related to AG 2-1 and AG 2-2 IIIB but distinguishable from the AG 2-1 and AG 2-2 LP isolates by the average linkage cluster analysis. These results suggested that the percentage composition of total-cellular fatty acids is a distinct characteristic for the five ISGs belonging to AG 2, and fatty acid analysis is useful for the differentiation and characterization of these ISGs of AG 2 in R. solani.

Grouping of Binucleate Rhizoctonia Anastomosis Group D (AG‐D) Isolates into Subgroups I and II Based on Whole‐Cell Fatty Acid Compositions

“…In addition, dierences of two to three times in percentage composition of the three major fatty acids: palmitic, oleic and linoleic acids were detected between the two subgroups (Table 2). Similar dierences were detected in the percentage composition of oleic acid between the closely related morphological types of R. solani AG-2±2 IV and AG-2±2 LP (Stevens-Johnk and Jones, 1993; Matsumoto and Matsuyama, 1999). They reported that the percentage composition of oleic acid of R. solani AG-2±2 IV were approximately two times lower than that of AG-2±2 LP.…”

The advancing identification and classification of Rhizoctonia spp. using molecular and biotechnological methods compared with the classical anastomosis grouping

“…A slightly modified MIDI method was successfully used to characterize MNR AGs (Johnk and Jones 1992). Subgroups of the following MNR AGs were differentiated with this method: AG 2 Matsumoto and Matsuyama 1999), AG 3 , and AG 4 (Johnk and Jones 2001). However, AG 1-IA could not be differentiated from AG 1-IB, although AG 1-IC isolates were distinct (Johnk and Jones 1994;Priyatmojo et al 2001).…”

A survey on basal resistance and riboflavin-induced defense responses of sugar beet against Rhizoctonia solani

“…Rhizoctonia solani anastomosis group (AG) 2-2 IV, the causal agent of root rot and foliar blight diseases (Matsumoto and Matsuyama, 1999) is one of the most destructive pathogens of sugar beet with high yield losses worldwide. Because of the high variability in the Rhizoctonia populations, its wide host range and long-term survival in soil, management of diseases caused by this necrotrophic fungus is difficult (Taheri et al, 2007).…”