First report of Rice stripe necrosis virus in Argentina

Since 2008/2009, we have seen symptoms of viral infection in rice plants from crop regions in Argentina. The main objective of this work was to identify the causal agent of the rice plants' crinkling. We therefore analyzed samples of symptomatic rice plants from Berón de Astrada (Corrientes province) and San Javier (Santa Fe province) by serological, electron microscopy and RT-PCR methods, and determined the presence of Rice stripe necrosis virus (RSNV). Helically constructed rod-shaped virus particles, with an axial canal with an estimated modal length of 228 nm, 370 nm and a last interval of 87-181 nm and a diameter of 20 nm, were observed in ultrathin sections and ISEM-D from rice leaf samples. Transmission of RSNV by viruliferous soil was achieved. Phylogenetic analysis, based on a partial sequence (828 nt) of the helicase gene of 10 RSNV isolates, grouped the Argentinian sequences in the same clade as the African, rather than with the sequence from Colombia. This is the first report not only of the presence of RSNV in Argentina, but of a viral infection in rice plants in the country.