Detection and Pathotype Identification of Pepper Mild Mottle Virus in Sweet Pepper Seeds from Taiwan

The seed-transmitted viruses were detected in sweet pepper(Capsicum annuum L.)seeds from Taiwan,using double antibody sandwich-enzyme linked immunosorbent assay(DAS-ELISA),reverse transcription-polymerase chain reaction(RT-PCR)and sequencing,and the sweet pepper cultivar L resistance gene was detected by PCR using sequence characterized amplified region(SCAR)marker primers.The results of DAS-ELISA and RT-PCR showed that Pepper mild mottle virus(PMMoV)were found in the seeds.Sequence determination results proved that the fragment was composed of coat protein of PMMoV,sharing identities of 92.4%~99.8% with other PMMoV isolates at nucleotide level.The amino acid sequence analysis showed that this isolate(disignate TW isolte)belonged to P1,2,3 pathotype of PMMoV.The detection result of L resistance gene showed that this sweet pepper cultivar possessed L3 resistance gene.The TW isolate was able to systemically infect this sweet pepper cultivar and suggested that it had overcome L3 gene-mediated resistance.This is the first report of P1,2,3 pathotype of PMMoV in China and it would have guiding significance in pepper resistance breeding.