Analysis of genetc diversity of Xanthomonas citri subsp citri strains. Characterizaton of a new isolate which triggers a host-specifc response

SICILIANO M. F.; CHIESA M.A.; ORNELLA L.; PINO DELGADO N.; FAVARO M. A.; SENDÍN L.N.; ROESCHLIN R.A.; ORCE I.G.; PLOPER, D.; VOJNOV A. A; FILIPPONE M.P.; CASTAGNARO A. P.; MARANO M. R.

Congreso; XII International Citrus Congress; 2012

Citrus is an economically important fruit crop that is severely aficted by Asiatc Citrus Bacterial Canker (CBC), a disease caused by Xanthomonas citri subsp. citri (XC). Argentna is one of the world´s largest citrus producers, accountng for 17% of global lemon supply, with the majority of producton concentrated in the northwestern province of Tucuman. To gain insight into the genetc diversity of Xanthomonas causing CBC in Tucuman, a total of 42 Xanthomonas isolates were collected from diferent citrus species across seventeen diferent orchards and subjected to molecular, biochemical and pathogenical tests. Analysis of genome- specifc XC markers and DNA polymorphism based on rep-PCRs showed that all isolates belonged to XC. Thirty-eight haplotypes with relatvely high genomic inter-relatonship compared to XC reference strains were discriminated. Pathogenicity tests showed that one isolate, named XCT44, which shares 91% genetc similarity to the reference strain XCT, has specifc host range. XCT44, induces a hypersensitve-like response in Citrus limon and Citrus paradisi leaves and weak canker lesions in Citrus aurantfolia and Citrus clementna XII INTERNATIONAL CITRUS CONGRESS 2012 - 209 S12 leaves. Although XCT44 produces less exopolysaccharides than the reference strain XCT, this defciency is not involved in the phenotype observed in C. limon leaves. This study consttutes the frst report on the characterizaton of XC in the northwest of Argentna.