title: Quantification of African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV-UG) in single and mixed infected Cassava (Manihot esculenta Crantz) using quantitative PCR.
abstract: The quantity of genomic DNA-A and DNA-B of African cassava mosaic virus (ACMV) and East African cassava mosaic virus Uganda (Uganda variant, EACMV-UG) was analysed using quantitative PCR to assess virus concentrations in plants from susceptible and tolerant cultivars. The concentrations of genome components in absolute and relative quantification experiments in single and mixed viral infections were determined. Virus concentration was much higher in symptomatic leaf tissues compared to non-symptomatic leaves and corresponded with the severity of disease symptoms. In general, higher titres were recorded for EACMV-UG Ca055 compared to ACMV DRC6. The quantitative assessment also showed that the distribution of both viruses in the moderately resistant cassava cv. TMS 30572 was not different from the highly susceptible cv. TME 117. Natural mixed infections with both viruses gave severe disease symptoms. Relative quantification of virus genomes in mixed infections showed higher concentrations of EACMV-UG DNA-A compared to ACMV DNA-A, but a marked reduction of EACMV-UG DNA-B. The higher concentrations of EACMV-UG DNA-B compared to EACMV DNA-A accumulation in single infections were consistent. Since DNA-B is implicated in virus cell-to-cell spread and systemic movement, the abundance of the EACMV-UG DNA-B may be an important factor driving cassava mosaic disease epidemic.
authors.affiliation: COMSATS Institute of Information Technology, Islamabad, Pakistan. Electronic address: saadia.naseem@comsats.edu.pk.
authors.forename: Saadia
authors.initials: S
authors.lastname: Naseem
authors.affiliation: Plant Virus Department, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures DSMZ, Braunschweig, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Winter
mesh_terms: D000349:Africa; D053839:Begomovirus / Q000235:genetics / Q000302:isolation & purification*; D002365:Manihot / Q000821:virology*; D018515:Plant Leaves / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction; D014454:Uganda
keywords: African cassava mosaic virus; East African cassava mosaic virus; Genome components; Kinetic PCR; Single and mix infections