Diversity of isolates of Rhizoctonia solani AG-1 1A and their relationship to other anastomosis groups based on pectic zymograms and molecular analysis

Reference strains of Rhizoctonia solani from AG-1 1A, -1-1B, 1-1C, 2-1, 2-2, and 3 to 9, isolates of AG-1 1A from various rice growing countries and field isolates from a paddy rice field experiment in Cote d'Ivoire were analysed by pectin enzyme analysis. A subset of these isolates was also analysed by A+T-rich DNA (AT-DNA) RFLPs, both with the objectives to study the diversity at various taxonomic levels and to obtain a clearer picture of the relationships between these isolates. Field isolates were submitted to simple sequence repeat PCR (SSR-PCR). Pectin enzyme analysis as well as AT-DNA RFLP showed that isolates of different anastomosis groups generated very distinct patterns. Isolates of AG-1 1A from various countries had a lower degree of variability in zymogram patterns and AT-DNA RFLPS, while zymograms and AT-DNA RFLPs of field isolates obtained from one field experiment consisted of one identical pattern. However, these isolates showed variation in RFLPs obtained through SSR-PCR, indicating that they were not clones sensu stricto.