Ageratum conyzoides L. plants affected with yellow vein disease were collected from Magelang, Bandung, and Purwokerto locations in Indonesia during 2001. A. conyzoides is a naturally occurring weed that is found in and around fields of cultivated pepper (Capsicum annuum L.) and tomato (Lycopersicon esculentum L.). It is frequently found with symptoms of yellow vein disease and the abundance of whiteflies on the affected plants suggested the possible involvement of a geminivirus. Total nucleic acids were extracted from nine samples collected from these locations of A. conyzoides-affected plants exhibiting yellow vein disease and amplified using PCR with geminivirus DNA-A-specific designed primers (virion-sense primer 5′-GAGCTCTTAGCCGCCTGAATGTTC-3′; complementary-sense primer 5′-GAGCTCGTCAGATGTTAAGACCTAC-3′) (1). A PCR-amplified product of approximately 2.7 kbp was obtained from each sample. Five independent sequences were cloned and sequenced from each sample. Sequence analysis showed that five of nine samples were Ageratum yellow vein virus (one each from Bandung and Purwokerto and three from Magelang) and the remaining four samples (two samples each from Bandung and Purwokerto) were a strain of Pepper yellow leaf curl Indonesia virus (PepYLCIDV). Full-length DNA-A of PepYLCIDV from systemic A. coniziodes was amplified using PCR with additional primers designed at only one restriction site (BamHI) (5′-GGATCCGCTTGTTCATCCTTTTCCAG-3′/5′-GGATCCCACATCTTTGGTTAGTGGAGGGTG-3′) and cloned. Three independent clones obtained were sequenced and analyzed. The sequence of a full-length DNA-A component was determined (2,760 bases, GenBank Accession No. AB267838). PCR using degenerate primers (DNABLC1: 5′-GTVAATGGRGTDCACTTCTG-3′; DNABLC2: 5′-RGTDCACTTCTGYARGATGC-3′, DNABLV2: 5′-GAGTAGTAGTGBAKGTTGCA-3′) of begomovirus DNA-B component (2), five independent clones were obtained and sequenced. Primers designed to amplify a full-length B component were constructed around a unique restriction site (BamHI) (5′-GGATCCCCTCATTCCTTTTGCGGAG-3′/5′-GGATCCACAGAGGAAAACTCGCAAGGC-3′). A PCR product was obtained from A. conyzoides samples and three independent clones were sequenced and analyzed. A full-length sequence of a begomovirus B component was determined (2,746 bases, GenBank Accession No. AB267839). Five open reading frames (ORF) were found in DNA-A and two in DNA-B. The DNA-A and DNA-B had a common region (CR) (74% nucleotide sequence identity) that comprised approximately 160 nucleotides. The DNA-A and DNA-B had an identical 31-base stem loop region in the CR. In addition, DNA-A and DNA-B had the highest nucleotide sequence identity (93%) with those of PepYLCIDV (GenBank Accession Nos. AB267834 and AB267835), suggesting it is a strain of PepYLCIDV, which is widely prevalent in Indonesia. To our knowledge, this is the first report of PepYLCIDV isolated from A. conyzoides plants affected with yellow vein disease.
References: (1) R. W. Briddon and P. G. Markham. Mol. Biotechnol. 1:202, 1994. (2) S. K. Green et al. Plant Dis. 85:1286, 2001.