Biological and Molecular Variability of Zucchini yellow mosaic virus in Iran

Zucchini yellow mosaic virus (ZYMV; family Potyviridae, genus Potyvirus) causes high yield losses to cucurbits in many parts of the world. The virus was detected for the first time in Iran in 1988, but the isolates have not been characterized. To study the genetic and biological diversity among Iranian ZYMV isolates, a set of twelve isolates, obtained during an extensive survey conducted from 2003 to 2006 in the major cucurbit-growing areas, were characterized. An experimental host range study of these isolates (referred as Iran-1 to Iran-12) revealed some variation in their biological properties. The nucleotide sequences of the genomic portion spanning the C-terminal part of NIb and N-terminal part of coat protein (CP) coding region were determined and compared with other available sequences. The identity among Iranian ZYMV isolates at the amino acid level reached 95.6-100%. The Iranian ZYMV isolates did not form a compact cluster in the phylogenetic tree, and the phylogenetic analyses and the estimation of genetic distance indicate that the Iranian ZYMV group consists of several independent introductions that evolved separately.