Sequence variation of the rDNA ITS regions within and between anastomosis groups in Rhizoctonia solani

Abstract

Sequence analysis of the rDNA region containing the internal transcribed spacer (ITS) regions and the 5.8s rDNA coding sequence was used to evaluate the genetic diversity of 45 isolates within and between anastomosis groups (AGs) in Rhizoctonia 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 subgroup, 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 and IC within AG-1 and subgroups HG-I and HG-II within AG-4 were placed on statistically significant branches as assessed by bootstrap analysis. These results suggest that sequence analysis of ITS rDNA regions of R. solani may be a valuable tool for identifying AG subgroups of biological significance.

Assessing genetic diversity in the web blight pathogen Thanatephorus cucumeris (anamorph = Rhizoctonia solani) subgroups AG-1-IE and AG-1-IF with molecular markers

“…The subgroup separation was congruent with the dendrograms generated by cluster analysis of combined marker data. The ITS rDNA region is considered appropriate for establishing phylogenetic relationships of Rhizoctonia AGs and subgroups within AGs (Cubeta and Vilgalys 1997;Kuninaga et al 1997), and PCR primers based on highly conserved regions of the rDNA unit have been designed for diagnostic purposes for many fungi (Klich and Mullaney 2004). However, assessing population diversity of closely related species through polymorphism at the ITS 5.8S rDNA level has its limitations.…”

“…The anastomosis subgroup results and isolate collection data are presented in Table 1. Isolate TC751 was assigned to subgroup AG-1-IA, and isolates TC754A, TC754B and TC755 were assigned to subgroup AG-4 on the basis of specific primer amplifications (Godoy-Lutz et al 2008;Kuninaga et al 1997).…”

“…As a species, R. solani is composed of a large complex assemblage of anastomosis groups (AGs) that are genetically distinct nonmating populations showing a wide diversity in morphology, pathogenicity and physiology (Kuninaga et al 1997;Ogoshi 1987;Sneh et al 1991). Isolates of R. solani can exist simultaneously as bi-or multinucleate homokaryons or heterokaryons possessing either homothallic (asexual), bipolar or heterothallic mating systems resulting in a variety of mechanisms for generating genetic diversity within AGs (Adams 1996;Cubeta and Vilgalys 1997).…”

New Anastomose Group of Binucleate Rhizoctonia Causing Leaf Wilt Disease of Erica sp

“…And some similar genetic sequences to those of Erica were downloaded from the NCBI (National Center of Biotechnology Information) web site, and then all the genetic sequences were put together so that phylogenetic tree were established by MEGA6 software [11].…”

RAPD e ITS Detectan Variación Molecular en Poblaciones Chilenea de Beauveria bassiana

“…Mayor variabilidad fue detectada en la región ITS 1, hecho que se ha detectado en otras especies de hongos (Becerra et al, 2006;Kuninaga et al, 1997;Zare et al, 1999). Al analizar ambas regiones ITS, se detectaron cinco haplotipos en los 36 aislamientos de B. bassiana, sólo los aislamientos Qu-B798c y Qu-B798b, ambos provenientes de Pencahue, VII Región, tienen un haplotipo único y distinto al de los otros aislamientos.…”