Occurrence and Distribution of Cassava Mosaic Begomovirus Related to Agro-ecosystems in the Sud-kivu Province, Democratic Republic of Congo

摘要

Cassava mosaic disease epidemiology and molecular characterization of the related viruses monitored during this study in the Sud-Kivu region, Democratic Republic of Congo. Collected epidemiologic data showed a negative correlation with the altitude (elevation) on the disease incidence and its vector population. Disease incidence was 9.5 to 37.8% associated to less than 3 insects per leaf when the elevation is higher than 1500 m while 65 to 100% and more than 10 insects per leaf were recorded where elevation was less than 1000 m. No impact of rainfall has been recorded. Associated molecular cassava begomovirus diagnostic focused on AC2 and AC4 genes revealed only two species occurring in this area, African Cassava Mosaic Virus (ACMV) and East Africancassava mosaic virus-Uganda (EACMV-UG) with more EACMV-UG and mixed infections in low elevation area while ACMV were predominant in high elevation sites. Phylogeny analysis revealed a dual coexistence of indigenous and Ugandan spread among ACMV isolateswhile all EACMV isolates were restricted to Ugandan spread (95 to 100% of amino acids identity). No recombination was revealed in this study, isolates diversity was restricted to nucleotide substitution.