Abstract:
Potyvirus is an economically important virus genus which limits the production of cucurbit crops worldwide. Given their importance, considerable effort worldwide has focused on characterizing and understanding these potyviruses. Somewhat surprisingly, almost no work has focused on the Pacific. This project aimed to characterize the molecular variability of two important cucurbit potyviruses [Zucchini yellow mosaic virus (ZYMV) and Papaya ringspot virus (PRSV)] in ten Pacific Island Countries and Territories [PICT] through the molecular analysis of the coat protein. Their molecular variability was then contextualized through comparing and contrasting them with worldwide samples via phylogenetic analyses and adaptive selection tests. Both ZYMV and PRSV PICT sequences grouped according to geographic origin and had strong purifying selection that varied in its intensity along the codons of the coat protein with a number of codons having neutral selection. The ZYMV PICT sequences grouped into the three subgroups I, II and IV of group A. The Samoan and Tongan sequences grouped in A-IV with Japanese and New Zealand sequences which are cucurbit trade partners; Vanuatu and Nauru grouped in A-I; and New Caledonian and Federated States of Micronesia grouped in A-II. The PRSV sequences split into two groups; the Commonwealth of the Northern Marinara Islands with the Asia group, and all the remaining in the Americas group. This information may assist biosecurity agencies, growers and researchers in the selection of virus-resistant cucurbit crops within the Pacific.
