Bioinformatics study on the role of homolog heat shock protein 70 gene of Iranian isolates of Cucurbit chlorotic yellows virus in increasing genetic variation

Heat shock proteins in Closteroviruses play many roles, especially moving from cell to cell to create systemic contamination. In the present study, the genetic differences of the heat shock protein gene of Iranian isolates of Cucurbit chlorotic yellows virus. Also, the selection pressure imposed on selected isolates was estimated and the. For this purpose, 195 samples with symptoms such as yellowing, stunting and leaf deformations were collected. From the cucurbits field of Sistan and Baluchestan province and for 15 samples a 462 bp fragment using specific primers for the heat shock protein genetic region of the CCYV was amplified by RT-PCR and 7 isolates were phylogenetically analyzed. The results showed that 7% of the samples were infected with Cucurbit chlorotic yellows virus in surveyed areas. Phylogenetic analysis of nucleotide and amino acid sequences showed that CCYV isolates were divided into two Iranian groups and East Asia, and isolates of Sistan and Baluchestan were divided into two separate branches. The putative amino acid sequence of heat shock protein alignment and Selection pressure studies on 7 isolates in the study with 3 Iranian isolates and isolates from other countries of this virus showed: the HSP70h gene in Iranian isolates and other isolates of this virus is under positive selection pressure at codon 82 leading to change of nucleic acid sequences (CTC to TTC) for isolates from the central regions of the province and isolates from Zabol, Hirmand and Nimroz at position 244, respectively, And the leucine amino acid has changed to phenylalanine in the heat shock protein. The results indicate that there are various CCYV isolates in the country, and the difference in nucleotide and amino acid sequences may reflect the differences in the host origin. Therefore, selection pressure has been implicated in the genetic diversity of the isolates.