Identification and Characterization of a New Strain of Sunflower chlorotic mottle virus, a Potyvirus Infecting Asteraceae in Argentina

摘要

Sunflower (Helianthus annuus L.) plants with chlorotic ringspot symptoms were observed during the 2005-2006 crop season in the Southeast of the province of Buenos Aires, Argentina. Symptomatic plants were tested by biological, serological and molecular assays, and the virus isolated was identified as a potyvirus closely related to Sunflower chlorotic mottle virus, common isolate (SuCMoV-C), the most prevalent virus in sunflower crops in the country. Infected plants were serologically positive when probed with a SuCMoV-C antiserum. In the 3o-terminus region, 1304 nucleotides (nt) were sequenced, and it includes the C-terminal region of the nuclear inclusion b protein (NIb) gene (240 nt), the whole capsid protein (CP) gene (807 nt) and a 3o-non-coding region (3o-NCR) with 257 nt excluding the poly (A) tail. The CP of the Sunflower potyvirus causing chlorotic ringspot (CRS) shared 94.8% aa identity with SuCMoV-C and 89.2% with SuCMoV-Zi. The 3o-NCR shared 94.2% nt sequence identity with SuCMoV-C. A RT-PCR/RFLP assay with PvuII and EcoRV restriction enzymes successfully differentiated SuCMoV-C and the virus isolate causing CRS symptoms. This potyvirus was identified as a new SuCMoV strain, provisionally designated SuCMoV-CRS.