Abstract

Rice yellow mottle virus is not only highly infectious to rice plants but also a highly variable pathogen. Forty-two isolates were obtained from five countries in West Africa. Utilizing 26 polyclonal antisera, the serological diversity of these isolates was determined using Double Immunodifusion Gel Assay. All the antisera were classified into three serogroups, PSg-1a, PSg-1b and PSg-2. Antisera belonging to PSg- 1a, PSg-1b andPSg-2 serogroups had diagnostic potential of 86-90%, 69-76% and 52-64%, respectively, for the 42 RYMV isolates analyzed using a dilution of up 1:200. Moreover, all isolates were separated into three serogroups, Sg-1a, Sg-1b and Sg-2. The first two groups are widely distributed across West Africa. The high diagnostic potential exhibited by the 26 RYMV polyclonal antisera indicates that Double Immunodifusion Gel Assay is useful and reliable for diagnosing RYMV. As the use of ELISA (Enzyme- Linked Immunosorbent Assay) is expensive and unavailable in most of the national agricultural research institute in West Africa, they can adopt Double Immunodifusion Gel Assay for the identification and characterization of Rice yellow mottle virus isolates. This is the first phylogenetic analysis report on the use of Double Immunodifusion Gel Assay to characterize Rice yellow mottle virus isolates in West Africa.

Key words: Rice yellow mottle virus, rice, double immunodifusion gel assay, phylogenetic tree, polyclonal antisera, serological diversity, West Africa