Abstract

M. Makwarela, N.J. Taylor, C.M. Faquet and M.E.C. Rey*

Cassava mosaic disease (CMD) is undoubtedly the most widespread disease in cassava (Manihot esculenta Crantz) in sub-Saharan Africa. While African cassava mosaic virus-Kenya (ACMV-KE), African cassava mosaic virus-Uganda (ACMV-UG), African cassava mosaic virus-India (ACMV-IC), East African cassava mosaic virus-Cameroon (EACMV-CM) and a recombinant East African cassava mosaic virus-India/Cameroon (EACMV-CM/IC) can be transmitted easily and repeatedly to Nicotiana benthamiana plants, difficulty in mechanical transmission and multiplication of EACMV-UG and South African cassava mosaic virus (SACMV) in N. benthamiana appears to place them biologically in a different group. In vitro grown 3-week-old cassava plants were biolistically inoculated with SACMV DNA A and B dimers and infectivity measured using a system based on visual assessment. We report for the first time successful infection, induced by SACMV DNA A and B dimer, of cassava cultivar TMS60444 using biolistic inoculation. Typical mosaic symptoms started to show at 14 days post-inoculation (dpi) in infected cassava plants, and SACMV replication was confirmed using PCR. Potential applications of biolistic infection of SACMV are also discussed.