Further genomic characterization of pineapple mealybug wilt-associated viruses using high-throughput sequencing

Abstract

In this study, we describe the further genomic characterization of several pineapple mealybug wilt-associated virus (PMWaV) members of the genus Ampelovirus, family Closteroviridae, using high-throughput sequencing (HTS). PMWaV-2 is a necessary factor in the complex etiology of mealybug wilt disease of pineapple (MWP). The complete PMWaV-1 genome was described previously, but the genomes of PMWaV-2, PMWaV-3, and putative PMWaV-4 and PMWaV-5 species lack complete characterization. To further study MWP etiology through genomic characterization of PMWaVs, a cDNA library from total RNA of pineapple plants was generated and underwent HTS. A PMWaV-4 genome of 12,932 nucleotides was assembled from the HTS data. Proteins from the PMWaV-4 genome shared high amino acid similarity to those of PMWaV-1. The RNA-dependent RNA polymerase (RdRp), heat shock protein 70 homolog (HSP70h), and coat protein (CP) proteins of PMWaV-4 shared 88, 87, and 85% amino acid identity, respectively, to those of PMWaV-1 (AF414119) indicating PMWaV-4 is a distinct strain of PMWaV-1 but not a distinct ampelovirus species. Therefore, we suggest that PMWaV-4 be designated PMWaV-1 strain 4 (MN539275). Further, we used HTS to obtain a new isolate of PMWaV-1 (MN539276) and supplemented the available sequences of the genomes of PMWaV-2 (MN539272 and MN539273) and PMWaV-3 (MN539274) in their 5′-terminal regions.