Occurrence of a new orange variant of Curtobacterium flaccumfaciens pv. flaccumfaciens, causing common bean wilt in Iran.
A new orange variant of Curtobacterium flaccumfaciens pv. flaccumfaciens was isolated from seeds of common bean cv. Daneshkadeh and Dehghan stored in the seed banks in Khomein Bean Research Station, and field plants (cv. Local Khomein) in Arak, Iran. The pathogenicity of the isolates was confirmed on 5- to 7-day-old seedlings of cv. Daneshkadeh. Marginal necrosis and interveinal chlorosis on first trifoliate leaves were observed 10-15 days after inoculation. Amplification of 306 bp fragment of orange-pigmented strains using CffFOR2- and CffREV4-specific prime pair characterized them as C. flaccumfaciens pv. flaccumfaciens. Although the yellow-pigmented variant of the causal agent was previously reported on cowpea, this is the first report of orange variant of C. flaccumfaciens pv. flaccumfaciens causing bacterial wilt on common bean in Iran.