Résumé
The rice stripe necrosis virus (RSNV, Benyvirus) is a bipartite virus, present in West Africa and emerging in South America. It is transmitted to rice by a soil protist, obligate endoparasite of rice roots, Polymyxa graminis (Pg). The diversity, biology and specificity of this tripartite interaction are poorly known, and no effective means of control are available to date. Our objective is to improve knowledge on the infection process of rice by RNSV. To better control the inoculation, we are developing cDNA infectious clones by homologous recombination in yeast and fusion PCR. Introns are inserted to prevent the toxicity of the Triple Gene Block proteins previously observed for another benyvirus, namely BNYVV. Different inoculation methods of the RSNV clones will be tested in controlled conditions, and compared to Pgmediated inoculation. The symptomatology, multiplication rate and viral movement will be monitored in plants. The specificity of the rice/Pg/RSNV interaction will be evaluated using different lineages of both the vector and the virus. Based on the methodologies developed, we will characterize the single resistance source identified so far and screen for others in representative accessions of rice. The results obtained here will contribute to the development of tools for the study of the tripartite interaction as well as the identification of efficient and durable control methods.