First Report of Rice stripe necrosis virus Infecting Rice in Burkina Faso.

Rice stripe necrosis virus (RSNV) was first described in 1977 as a new virus infecting rice in Cote d'Ivoire (3) and was subsequently observed in Liberia, Nigeria, and Sierra Leone (2). RSNV is a soil-borne virus transmitted by the fungus Polymyxa graminis (1) and belongs to the genus Benyvirus (4). During a survey carried out in April of 2013, severe symptoms characterized by seedling death, severe plant malformation, and foliar striping were observed on rice plants in an experimental field of INERA at Banfora located in western Burkina Faso. Disease incidence in the field was estimated to be 80 ± 5%. The symptoms of disease were successfully transmitted to the susceptible rice (Oryza sativa) cultivar IR64 by soil transmission experiments (1). RSNV was detected by ELISA using a polyclonal antiserum (1), kindly provided by Dr. Denis Fargette, IRD, Montpellier, France. Total nucleic acid was extracted with TRIzol reagent (Invitrogen) from IR64 and field infected samples. The presence of the virus was confirmed by RT-PCR using primers 5'-CATCTTGTCGAGATGAG-3' and 5'-GCGTTGTCTTTATCAGTG-3' for specific sequences flanking the RNA2 CP gene. The RT-PCR product was directly sequenced and the sequence was deposited in GenBank (Accession No. LK023710). Sequence analysis showed that the CP gene of the RSNV isolate from Burkina Faso shared the highest nucleotide sequence identity (97.6%) with the known RSNV CP gene sequence from the Colombian isolate (EU099845) available in GenBank, confirming the presence of RSNV in the rice crops in Burkina Faso. To our knowledge, this is the first confirmed report of RSNV in Burkina Faso. Further studies are needed to determine its incidence and spread in the country. Detection of RSNV in Burkina Faso signals the urgent need for adoption of appropriate measures to restrict the spread and impact of this virus within Africa. References: (1) C. Fauquet and J. C. Thouvenel. Proc. Acad. Sci. Ser. D 296:575, 1983. (2) C. Fauquet et al. Develop. Appl. Biol. 2:71, 1988. (3) D. Louvel and J.-M. Bidaux. Agronomie Tropicale 32:257, 1977. (4) I. Lozano and F. Morales. Eur. J. Plant Pathol. 124:673, 2009.