Complete genomic sequence of a Papaya ringspot virus isolate from Hainan Island, China

Abstract

Papaya ringspot virus (PRSV, genus Potyvirus, family Potyviridae) causes significant yield losses in papaya and in some cucurbits throughout tropical and subtropical regions [7]. Based on its host specificity, PRSV is classified into two biotypes. Type W is known to infect only cucurbits, whereas type P infects both papaya and cucurbits. The first PRSV genome completely sequenced and characterized was the Hawaiian isolate, PRSV-H [11]. The complete sequences of a number of PRSV isolates have since been determined [2, 3, 5, 6, 10]. Hainan Island, having 1,300 ha of papaya plantation and an annual output of 70,000 tons, is the most important papaya-producing region in China. The papaya ringspot disease has been and will remain a major challenge in papaya production in Hainan. The disease in Hainan displayed typical symptoms of PRSV infection [11]. However, the causative virus and its relationship with other PRSV isolates have not been characterized. Understanding the exact nature of the PRSV in Hainan is important for the management of the disease. This importance is apparent in light of recent reports that described different specificities of PRSV resistance displayed by transgenic papaya lines expressing different PRSV CP genes toward PRSV isolates from different geographic origins [8, 9]. In this paper, we report the complete genomic sequence of PRSV (PRSVHN) from the Hainan Island, China, and present evidence that PRSV-HN represents a unique and novel PRSV isolate.