A Bromoviridae member associated with chlorotic leaf symptoms on sunflowers.

GIOLITTI, FABIÁN; NOME CLAUDIA; VISINTIN GRISELDA; DE BREUIL SOLEDAD; BEJERMAN, NICOLÁS; LENARDON, SERGIO

Congreso; 18th International Sunflower Conference; 2012

Sunflower (Helianthus annuus L.) plants showing chlorotic concentric ring and linear pattern symptoms were observed near Paraná city, (Entre Ríos Province) in commercial sunflower crops. The aim of this study was to characterize this new sunflower disease.  Infected plants were tested by biological, serological, molecular and electron microscopy assays. Virus transmission efficiency by mechanical inoculation was near by 100%, to sunflower plants at the V2 vegetative stage. Seed transmission was negative as plants derived from seeds of systemically infected plants showed no symptoms. A host range including 27 species of the families Amaranthaceae, Asteraceae, Chenopodiacea, Cucurbitaceae, Dipsacaceae, Fabaceae and Scrophulariaceae was tested, and 59.26% of inoculated species showed positive plants to viral infection. Electron microscopy of rapid preparations from samples enriched with the virus revealed high concentration of quasi-spherical particles of 33 nm diameter. Total RNA extracted from a viral enrichment sample was pyrosequenced resulting in 655 sequences (isotigs), three sequences with 3336, 2388 and 2592 pb, presenting 89.8%, 94.8% and 89.5% of identity with RNA1, RNA2 and RNA3 of Pelargonium zonate spot virus (PZSV), respectively. These results indicate that the virus associated with chlorotic concentric ring and linear patterns symptoms in sunflower is a member of the Bromoviridae family closely related to PZSV, a virus that has been reported in different Europeans countries. This is the first mention of a virus member of the Bromoviridae family infecting sunflower in Argentina. These results will allow further epidemiological and characterization studies of the disease.