A New Geminivirus Associated with a Yellow Leaf Curl Disease of Pepper in Thailand

Pepper (Capsicum anuum) plants affected with yellow leaf curl disease were observed at Kanchanaburi in central Thailand in 1995. Three naturally infected pepper plants showing yellow leaf curl were collected and virus cultures maintained in pepper plants. Transmission experiments were carried out with the whitefly vector (Bemisia tabaci Genn.). Acquisition and inoculation threshold periods were 1 h and 30 min, respectively. The latent period was 10 h. Symptoms in cultured plants were the same as those observed in field plants. DNA was extracted from these cultured plants and amplified using polymerase chain reaction (PCR) with geminivirus-specific degenerate primers (1). A PCR product of 2.7 kbp was amplified and cloned. Three independent clones were sequenced and analyzed, and an identical 32-base stem loop region and the unique sequence (TGGGGTC) of putative Rep binding site were found in the intergenic region (IR). The B component could not be detected. The nucleotide sequence of the coat protein gene was compared with 28 well-studied whitefly-transmitted geminiviruses. Our geminivirus showed the highest sequence similarity (85%) with Tomato leaf curl virus from Taiwan (TwToLCV: GeneBank accession number U88692), suggesting that it is a new geminivirus. Therefore, it is designated Pepper yellow leaf curl virus. Reference: (1) M. R. Rojas et al. Plant Dis. 77: 340, 1993.