[Molecular identification of Araceae-infecting viruses and their ecology]

A filamentous virus and a spherical virus were detected from partial purification with natural-infected Araceae plants. The filamentous virus was confirmed as dasheen mosaic virus (DsMV) by RNA spot hybridization (RSH) and sequence determination, while the spherical virus was identified as a new strain of cucumber mosaic virus (CMV) by enzyme-linked immunosorbent assay and sequence determination of the 3' end genes of RNA3. CMV was firstly confirmed as one of the principal viruses infecting the Araceae plants under natural condition. According to the sequence similarity of coat protein, Araceae-infecting CMV was then decided belonging to CMV subgroup I, but independent from other isolates in this subgroup. By dot-RNA hybridization to DsMV and CMV probes with total RNA extracted from leaf tissue, field samples collected from some parts of southern China were detected for their natural infection. The infection ratio of field samples infected by DsMV and CMV were 73.3% and 46.7% for samples collected from Hainan Province, 100% and 38.5% for those from Hunan Province, 93.0% and 38.5% for that from Zhejiang Province, and 100% and no infection for samples from Shanghai, respectively. The infection of viruses on Araceae plants was obviously affected by such ecological factors as geological distribution, climate and host species. The occurrence of CMV was greatly influenced by the above factors, but DsMV always existed as the most commonly distributed virus.