Detection of begomoviruses and associated satellites in viruliferous whiteflies for surveys of leaf curl disease in feral papaya and non-papaya hosts

Papaya is an important horticultural crop in the tropics. It is host to various debilitating plant viruses that cause reduced crop yields and economic loss to farmers. Papaya leaf curl disease in India is caused by whitefly-transmitted Begomoviruses belonging to the single-stranded DNA viruses of family Geminiviridae. Papaya leaf curl disease can also co-occur with Papaya ringspot disease caused by the positive stranded RNA potyvirus; Papaya ringspot virus (PRSV) transmitted by aphids. In a long-term survey of feral and cultivated papaya plants showing typical symptoms, a large diversity of Begomoviruses was detected (Singh-Pant et al., Arch. Virol., 2012). Continuation of the survey over a decade since of an area about 827 square kilometres revealed persistence and emergence of distinct monopartite Begomovirus complexes in symptomatic papaya and neighbouring, non-papaya plants. It can be assumed that the distribution and abundance of these Begomoviruses is related to viruliferous whiteflies in the region. In order to establish the role of the vector in disease transmission and prevalence, we report standardization of PCR-based methods to detect genomic components (viral DNA A, DNA B, and/or satellite molecules) in iso-female lines of Bemisia tabaci derived from natural populations sampled from several host plants. Virus sequences detected in these whiteflies, typed by their mitochondrial cytochrome oxidase gene sequences, are available as GenBank accessions OM365985, OM365983, OK236818, ON054966, OM365980, OP490299, OP514974, OP535158, OP535159, OP535160, OP535161.