First Report of Pepper vein yellows virus Infecting Hot Pepper in Pakistan

Abstract

During June 2014, approximately 65% of hot pepper (Capsicum annum) plants in a commercial field in Multan district of Pakistan showed symptoms of curling, deformation, and interveinal leaf yellowing. Such symptoms are usually produced by either nutritional disorders or polerovirus infection (Tomassoli et al. 2016). Twenty randomly collected symptomatic and two asymptomatic (control) leaf samples were tested by double antibody sandwich (DAS)-ELISA using antiserum of Cucurbit aphid-borne yellows virus (Sediag, Longvic, France), which is known to cross-react with Pepper vein yellows virus (PeVYV) (Afouda et al. 2017). Seven of the 20 symptomatic samples were positive in DAS-ELISA. Total RNA from all ELISA-positive samples isolated by TRIzol reagent (Life Technologies, Carlsbad, CA) was used in one-step RT-PCR using the generic primers targeting the RdRp coding conserved sequence of Polerovirus (Lotos et al. 2014). The resulting amplicons were purified using Amicon Ultra kit (EMD Millipore, Billerica, MA) and directly sequenced in both orientations (BioFab, Rome, Italy). The sequences were identified as 594 bp of the P2 protein gene of the PeVYV genome using BLASTn analysis. The sequences of four isolates were found to be identical, so the sequences of three isolates were submitted to GenBank under accession numbers KX121043–45. Pakistani isolates shared 98 to 99% nucleotide sequence identities with each other and 93 to 96% with previously reported PeVYV isolates. All isolates shared 96% identity with Japanese (LC126041–45) and Israeli (HM439608) isolates and 94% identity with isolates from Australia (KU999109) and Greece (LT559484). To our knowledge, this is the first report of PeVYV from Pakistan. As in other countries around the world, the presence of PeVYV in Pakistan is threatening hot pepper cultivation. The fact that poleroviruses are aphid transmitted (Dombrovsky et al. 2010) supports the hypothesis that this virus may be present in other crops in various parts of the country. Therefore, further studies regarding incidence and distribution of this virus are needed.