First report of Polymyxa betae and Polymyxa graminis in Lebanon.
Field surveys on sugarbeet, wheat and barley crops were conducted between March and May 2007 in the Bekaa valley of Lebanon, to look for soilborne fungal vectors of viral diseases. A mixture of wheat (cv. Cham 4) and barley (cv. Black Arabic) seeds was sown in one of the pots while the other received sugarbeet (cv. Hilma) seeds, and both were grown for 8 weeks. The presence of resting spores (cystosori) of Polymyxa spp. was observed in the roots of plants grown in 20 soil samples, especially those from the central and west Bekaa. Pathogen identification was conducted by RT-PCR with primers specific for Polymyxa betae and Polymyxa graminis, using nucleic acids extracted from sugarbeet and wheat roots tissues as template. DNA fragments of 630 bp and 320 bp were amplified, as expected for P. betae and P. graminis, respectively. This is thought to be the first report of P. betae and P. graminis in Lebanon.