Identification And Analysis Of Complete Genomic Sequence Of Virus Isolates Infecting Luffa Cylindrica And Cucurbita Pepo L.

Luffa cylindrica is a Cucurbitaceae climbing herbaceous plant and growing in all parts of the country. It is one of the important melon vegetables in China. Cucurbita pepo L originating in South America, is an annual Cucurbitaceae herb attributes to Cucurbita and one of main vegetables too. With rising standards of living and rapid increasing of cultivated areas, virus infection in Cucurbitaceae have become increasingly serious. In this paper, we identified the pathogens in Luffa cylindrica and Cucurbita pepo L. with stunt virus symptoms in the farm of Pomology Institute, Shanxi Academy of Agricultural Sciences, and then we cloned and analyze the complete or partial sequences of the viruses isolate Luffa cylindrica and Cucurbita pepo L.(1) Identification the pathogens by Enzyme linked immunosorbent assay, the detection results showed that Luffa cylindrica was positive with Cucumber Mosaic virus (CMV).(2) dsRNAs were extracted from symptomatic leaf samples from different plants and used as temples in SIA, results of PCR and sequencing showed that the Luffa cylindrica virus diseases were caused by complex infection of Cucumber Mosaic virus (CMV) and Zucchini Yellow Mosaic virus (ZYMV). At the same time, there was Watermelon Mosaic virus (WMV) on Cucurbita pepo L. And the name of CMV-SX, ZYMV-SX and WMV-SX are proposed.(3) To further characterize the CMV-SX, ZYMV-SX and WMV-SX, the MP gene of CMV-SX and the complete sequence of ZYMV-SX and WMV-SX were cloned and determined. Nucleotide sequence similarity searches showed that CMV-SX shared the identities (79.3%-96.3%) with other CMV strains, and amino acid homology at movement protein (MP) gene was relatively low.ZYMV-SX comprised 9593 nucleotides and had an ORF which encode polyprotein of 3080 amino acids. Nucleotide sequence similarity searches showed that ZYMV-SX shared identities (82.8%-98.2%) with other ZYMV strains. Phylogenetic comparisons based on amino acid sequences of ZYMV-SX and other isolates showed that ZYMV-SX formed an independent branch with KR-PA and KR-PS. Therefore, ZYMV-SX was most closely related to KR-PA and KR-PS. The results of recombination showed recombination event occurred in 2623 nt-5956 nt. The major parent and minor parent is WM, KR-PA, respectively.WMV-SX comprised 10049 nucleotides and had a typical Potyvirus genome organization with 1 ORF. Nucleotide sequence similarity searches showed that WMV-SX, in nucleotide Similarity, were from 89.8%to 94.6%to that of other WMV strains. Phylogenetic comparisons based on amino acid sequences of WMV-SX and other Potyvirus isolates showed that WMV-SX formed an independent branch with Dendrobium, FBR04-37, CHI87-620, C06-188, FMF00-LL2, TURK91 and 1R02-54. Therefore, WMV-SX was most closely related to Dendrobium, FBR04-37, CHI87-620, C06-188, FMF00-LL2, TURK91 and IR02-54. The results of recombination showed recombination event occurred in 3206 nt-9840 nt. The major parent and minor parent is WMV-FMF00-LL2, WMV-FBR04-37, respectively.