Archivio Journal of Plant Pathology

Abstract:

In May of 2008, the wide occurrence of Emilia sonchifolia plants with yellow vein symptoms was observed in the Chinese province of Fujian. Symptomatic plants were infected with Emilia yellow vein virus (EmYVV) (Yang et al., 2008). Subsequently, the presence of thickhead plants (Crassocephalum crepidioides) show- ing foliar yellow vein symptoms was noticed in proximity to symp- tomatic E. sonchifolia. Total DNA was extracted from symptomatic C. crepidioides leaves and tested by rolling circle amplification (Haible et al., 2006). Amplification products were digested by the restriction enzyme EcoRI for 30 min. Restriction products (2.7 kb) were then cloned and sequenced. Comparison of DNA sequences by Clustal V analysis revealed the occurrence of EmYVV and an isolate denoted Fz12 was selected for further sequence analysis. The genome of EmYVV isolate Fz12 was 2,726 nt in size and had the typical genomic organization of begomoviral DNA-A (Gen- Bank accession No. JQ247188). A BLAST analysis of the NCBI database disclosed that isolate Fz12 had the highest nucleotide se- quence identity (99.67%) with that of an EmYVV isolate from E. sonchifolia (GenBank accession No. EU377539). To our knowl- edge, this is the first report of the natural occurrence of EmYVV in C. crepidioides, a common weed species in the People’s Republic of China.