Biolistic inoculation of cassava (Manihot esculenta Crantz) with South African cassava mosaic virus

Abstract

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.