Diversity of rDNA-ITS sequences of <Emphasis Type="Italic">Polymyxa graminis</Emphasis> from wheat and barley in Japan

Polymyxa graminis is a soil-borne obligate organism that transmits bymoviruses and furoviruses to barley and wheat. We analyzed rDNA-ITS sequences of P. graminis from roots of wheat and barley in fields in Japan and obtained five kinds of sequences; two sequences were almost the same as known ribotype Ia and IIa, respectively, and three were close to ribotype Ib. When infection of P. graminis was examined using PCR, ribotype Ia was detected only in barley, but ribotypes Ib and IIa were detected in both wheat and barley. Our analysis suggested that Japanese ribotype Ib transmits furoviruses and bymoviruses.