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چکیده
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The causal agent of Asiatic citrus bacterial canker, Xanthomonas citri subsp. citri (Xcc), has three pathotypes: A, A* and Aw. A*-type strains have a restricted host range to Mexican lime and are classified into four subgroups, among which strains isolated from the Sistan-Baluchistan province in Iran have not been defined and reported anywhere else in the world. For comparative analysis, we determined the genome sequence of strain NIGEB-386 from this new A* subgroup. We also select complete genome sequences of XccA306 (type A strain), Xcaw12879 (type Aw strain) and draft genome sequences of two A* strains, XccA* LG115 (isolated from India) and XccA* JS581 (Iranian strain from other subgroups), from GenBank sequence databases. Approximately 98% of coding DNA sequences (CDSs) are shared by the three pathotype genomes and there are about 2% unique CDSs for each pathotype. XccA* NIGEB-386 and XccA* JS581 contain 28 putative Type III secretion system effectors; Xcaw12879 and XccA* LG115 contain 29; and XccA306 contains 27. Despite previous data on the presence of the AvrGf1 effector and its contribution to the host range limitation in Xcaw12879, the only effector gene is in XccA* LG115 and was not detected in two narrow host range Iranian strains. Additionally, the Lipopolysaccharide gene cluster of XccA* NIGEB-386 showed a high similarity to other host-limited strains, and significant differences with the broad host range strain, XccA306. Generally, Iranian A* strains show a close relationship together, while XccA* LG115 shares a close relationship with Xcaw12879.
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