Biological characterization, distribution and synergistic interactions of a Torradovirus with a Polerovirus infecting cassava in the Americas
M. CARVAJAL-YEPES (1), J. Jimenez (1), A. Quintero (1), W. Cuellar (1) (1) International center for tropical agriculture, Colombia

Field experiments in Colombia using clean cassava planting material showed that Cassava torrado-like virus (CsTLV) (family Secoviridae) and Cassava polero-like virus (CsPLV, family Luteoviridae), two novel viruses found in mixed infections in cassava affected by severe root symptoms are the first to accumulate during  growing season in 2014. We characterized isolates of CsTLV and CsPLV and studied its co-infection using grafting and sap-inoculations in cassava and a series of herbaceous hosts. CsTLV causes chlorotic spot symptoms in young cassava leaves while CsPLV did not induce any visible symptoms in leaves. None of them could be mechanically transmitted neither were they through botanical seed. Full genome analysis of CsTLV revealed the presence of a Maf/HAM domain. two other plant viruses have been reported to contain a Maf/HAM domain: Cassava brown streak virus and Euphorbia ringspot virus (family Potyviridae) and all have been isolated from species of the family Euphorbiaceae. Field surveys show the presence of CsTLV in three surveyed regions but it was more prevalent in province of Sucre (62%) were the percentage of root diseases was higher. Phylogenetic analyses of CsTLV isolates revealed wide sequence diversity and suggest the presence of at least three different strains that share between 80-85% a.a. similarity in the RdRp.. When CsTLV was tested in co-infection with CsPLV, root yield of cassava showed up to 90% decrease. The protein function of CsTLV Maf/HAM is under study.

Abstract Number: P3-66
Session Type: Poster