Occurrence and Molecular Characterization of Three Pineapple Mealybug Wilt-Associated Viruses in Pineapple in Taiwan

Pineapple (Ananas comosus) is one of the major fruit crops in Taiwan, accounting for 275 million U.S. dollars in 2006, following betel nut and citrus production in crop value. Tainung No. 17 is the most important cultivar, accounting for more than 70% of pineapples planted. Mealybug wilt of pineapple (MWP) is one of the most destructive diseases of pineapple. Pineapple mealybug wilt-associated virus-1 (PMWaV-1), PMWaV-2, and PMWaV-3 were identified as three distinct species in Ampelovirus from diseased Hawaiian pineapple (1,2). In November of 2007, pineapples (cv. Tainung No. 17) planted in Pingtung County of southern Taiwan showed symptoms similar to MWP. Mealybugs (Dysmicoccus brevipes) were also found. Three primer pairs, 225/226, 223/224, and 263/264 described previously specific for the HSP70h genes of PMWaV-1 (1), -2, and -3 (2), respectively, were used to detect the presence of these three viruses by reverse transcription (RT)-PCR. Expected DNA fragments of 590, 610, and 499 nt were obtained from t...