Genotypic characteristics of Xanthomonas arbaricola pv. juglandis, causal agent of walnut bacterial blight, based on Rep-PCR in Kohgiluye and Buyer- ahmad province

Walnut bacterial blight, caused by Xanthomonas arboricola pv. juglandis (Xaj) is one of the most important diseases, causing severe damage at the presence of moisture and the optimal temperature for the development of the disease. The aim of this study was walnut bacterial blight detection, in Kohgiluye and Boyer- Ahmad province and evaluation of genetic diversity of Xaj strains using rep-PCR.
During 2011-1012, several samples of walnut′s leaf and fruit, showed bacterial blight symptoms, were collected from Kohgiluyeh and Boyer- Ahmad province of Iran. Bacterial isolates were studied with bacteriological standard methods. Moreover, genetic fingerprint of Xaj strains were evaluated and phylogenetic tree of them was drawn.
Twenty five isolates of Xaj were showed small, relatively prominent with yellow colony. All isolates were oxidative, Gram and oxidase negative but catalase positive. They hydrolyzed starch and able to produce H2S from cystein ​​and formed yellow colonies on YDC medium.
On the basis of biochemical, phenotypical and virulence test, presence of Xaj in Kohgiluyeh and Boyer- Ahmad province, was revealed. This is the first report of walnut bacterial blight disease in Kohgiluyeh and Boyer-Ahmad province. Genotypic characterization of isolates also was assayed with rep-PCR. All isolates were similar at 73% similarity level, but any relationship among clusters and geographic area were not observed