First report of citrus bacterial canker caused by Xanthomonas axonopodis pv. citri in iraq

Abstract

      Collected citrus leaves, with erumpent, callus – like lesions with a water-soaked margin of Tangerine (Citrus reticulate Blance), Mexican lemon (Citrus limon), and Sweet orang (Citrus sinensis Osbec) from different orchards in Diyala, Baghdad and Babylon Governorate of Iraq. Pathogenicity of different isolates was confirmed along with symptoms under laboratory condition on detached leaf using pin prick method, observed that 21 (60 %) isolate Xac. was highly virulent to initiate water soaked lesion and fully developed symptoms within 10 to15 days, 14 (40 %) isolate Xac. were less virulent. The results of morphological (shape, colony and color) and biochemical characteristic (gram reaction, starch hydrolysis, gelatein liquefaction, KOH test, Indole production, oxidase reaction, acid and gas production, catalase reaction, fluorescent pigmentation test and NaCl tolerant). Molecular identification was performed by PCR using specific primer J-pth1̸ J-pth2 amplicon 198 bp indicated the occurrence of CBC in Iraq.  All isolates 35(100%) were harbor  pthA gene. These represent the first report of CBC in Iraq.