Genetic Characterization of Rhizoctonia solani AG-2-3 by Analyzing Restriction Fragment Length Polymorphisms of Nuclear Ribosomal DNA Internal Transcribed Spacers.

This report describes Rhizoctonia solani anastomosis group (AG)-2-3, a newly recognized pathogen of foliar blight of soybean. This group was separated from other subgroups of AG-2 analyzing the internal transcribed spacers (ITS) of nuclear ribosomal DNA repetitive units. The ITS regions of 35 isolates of AG-2, containing 17 isolates of AG-2-3, were amplified by the polymerase chain reaction and analyzed by digestion with 4 restriction enzymes (EcoRI, HaeIII, MspI and TagI). Clear restriction fragment length polymorphisms were found among AG-2 subgroups. The polymorphisms suggest that the group AG-2-3 is a genetically distinct subgroup of AG-2.