Genetic diversity among Xanthomonas citri subsp. citri strains in Iran

Abstract

Citrus bacterial canker (CBC) is one of the most important diseases of citrus. It is caused by Xanthomonas citri subsp. citri (Xcc). To investigate the variability of Xcc, a collection of twenty-five strains were isolated from the Fars, Hormozgan, Kerman and Sistan-va-Baluchestan provinces of Iran. The twenty-five strains were assessed phenotypically and genetically. These strains had similar biochemical properties. Based on host range determination, the strains were divided into two groups; the first group was pathogenic on Mexican lime (Citrus aurantifolia), citrumelo (Poncirus trifoliata x C. paradisi), citrange (C. sinensis x P. trifoliata) and sour orange (C. aurantium) varieties. The second group was pathogenic on Mexican lime only. Profile of cellular soluble proteins analyzed by sodium dodecyl sulphate-polyacryamid gel electrophoresis (SDS-PAGE) did not reveal any considerable differences among strains. Genetic diversity analyses were performed using two marker systems; repetitive polymerase chain reaction (rep-PCR) and random amplified polymorphic DNA (RAPD). The results of this research showed that two primers, ERIC 1R and 232, with the highest marker index, resulted in the most genetic variability among strains. Cluster analysis by band patterns showed that strains from the Sistan-va-Baluchestan province were a different group, so it was concluded that geographical origin of strains from the Sistan-va-Baluchestan province is different than the geographical origin of strains isolated from other provinces