S. Kuninaga et al., SEQUENCE VARIATION OF THE RDNA ITS REGIONS WITHIN AND BETWEEN ANASTOMOSIS GROUPS IN RHIZOCTONIA-SOLANI, Current genetics, 32(3), 1997, pp. 237-243
Sequence analysis of the rDNA region containing the internal transcrib
ed spacer (ITS) regions and the 5.8s rDNA coding sequence was used to
evaluate the genetic diversity of 45 isolates within and between anast
omosis groups (AGs) in Rhizoctonin solani. The 5.8s rDNA sequence was
completely conserved across all the AGs examined, whereas the ITS rDNA
sequence was found to be highly variable among isolates. The sequence
homology in the ITS regions was above 96% for isolates of the same su
bgroup, 66-100% for isolates of different subgroups within an AG, and
55-96% for isolates of different AGs. In neighbor-joining trees based
on distances derived from ITS-5.8s rDNA sequences, subgroups IA, IB an
d IC within AG-1 and subgroups HG-I and HG-II within AG-4 were placed
on statistically significant branches as assessed by bootstrap analysi
s. These results suggest that sequence analysis of ITS rDNA regions of
R. solani may be a valuable tool for identifying AG subgroups of biol
ogical significance.