مجله بیوتکنولوژی کشاورزی (May 2023)
Genetic Diversity and Pathogenicity of Xanthomonas translucens Strains Causing Bacterial Leaf Streak on Wheat in Khorasan Provinces
Abstract
Objective Bacterial leaf streak (BLS) caused by of Xanthomonas translucens, is a serious bacterial seed-borne disease of wheat (Triticum aestivum L.) worldwide. This research was planned to study pathogenicity of the isolates obtained from bacterial leaf streak on wheat plants. Resistance of different wheat cultivars against the isolate with the highest pathogenicity was investigated. Molecular tools were used to identify bacterial isolates and their genetic diversity. Materials and methods Bacterial strains with yellow and soft colonies were isolated and their pathogenicity indicated that all selected isolates are pathogen. Aggressiveness of the isolates was differing among isolates. Wheats cultivars showed different responses to selected isolate, but all cultivars were susceptible to the pathogen. Result of molecular analysis with DNA fingerprinting techniques showed genetic diversity among the bacterial isolates obtained from different wheat growing regions. In the cluster analysis of the banding pattern obtained with ERIC and BOX primers, the isolates were divided into 5 main groups at 33% similarity. The results showed significant genetic diversity among isolates causing bacterial leaf streak disease in these provinces. Sequences comparison of gyrB and dnaK genes with similar sequences in the gene bank showed high homology with sequences from Xanthomonas translucens pv. undulosa. Results Bacterial strains with yellow and soft colonies were isolated and their pathogenicity indicated that all selected isolates are pathogen. Aggressiveness of the isolates was differing among isolates. Wheats cultivars showed different responses to selected isolate, but all cultivars were susceptible to the pathogen. Result of molecular analysis with DNA fingerprinting techniques showed genetic diversity among the bacterial isolates obtained from different wheat growing regions. In the cluster analysis of the banding pattern obtained with ERIC and BOX primers, the isolates were divided into 5 main groups at 33% similarity. The results showed significant genetic diversity among isolates causing bacterial leaf streak disease in these provinces. Sequences comparison of gyrB and dnaK genes with similar sequences in the gene bank showed high homology with sequences from Xanthomonas translucens pv. undulosa. Conclusions The rep-PCR techniques are suitable for studying genetic diversity of the obtained isolates. In this study, geographical location had no effect on the grouping of the isolates. Bacterial leaf streak disease is found in almost every wheat growing area and better understanding of the Xanthomonas translucens-wheat interactions are necessary to find and develop wheat cultivars with resistance to the disease.
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