Isolation, cloning, sequencing and bioinformatic study of a resistance gene analogue against tomato mosaic virus in tow native types of cantaloupe to Iran

Cucurbita genus belongs to Cucurbitaceae family. These plants are attacked with different pathogenic agents. Currently the effective strategy to control many disease of Cucurbitaceae is the usage of resistant plants. In this study, the NBS domain encoded by resistance genes was studied in Iranian native varieties of cantaloupe. For this purpose, the seeds of Iranian native cantaloupe cultivars were provided and cultivated in greenhouse. DNA was extracted from leaves of different cultivars using CTAB method. Degenerate primers were designed from conserved motives of resistance analogues genes and amplification of these genes was performed using PCR method. The results showed the isolation of an analogous for resistance gene to tomato mosaic virus (ToMV) in cantaloupe cultivars TN-92-99 and TN-92-80 that were cloned in pGEM-T plasmid and then sequenced. Blast analysis indicates that NBS sequence in Irnian cantaloupe share 92% similarity with ToMV resistance gene in watermelon. Phylogenetic tree drawing using resistance gene analogues from cantaloupe and watermelon existing in NCBI gene bank created tow main groups and seven subgroups.Bioinformatic analysis revealed that these genes sequences are conserved among some native cantaloupe caltivars of Iran. Second structure study of protein of ToMV resistance gene analogus using PSIpred software indicates that these proteins only have α helix structure. This protein is secreted in plasma membrane and its extracellular secretion is very little.