Biological and molecular characterization of cucumber mosaic virus infecting watermelon in Serbia

Investigation of the presence and distribution of Cucumber mosaic virus in watermelon crops in Serbia during 2012 revealed that the virus was present in five out of six surveyed localities. CMV was detected in 24.05% of total serologically tested samples using DAS-ELI­SA method and the virus was the most prevalent in the locality of Silbaš. During this investigation, Cucumber mosaic virus was present more often in mixed infections with ZYMV and/or WMV (12.66%), while the single infection was detected in lower percentage, 11.39%. Five CMV isolates were obtained by mechanical inoculations of N. glutinosa and two of them were selected for further biological characterization. Concerning type and severity of symptoms on test plants, the investigated isolates exhibited different phenotypic features. Molecular detection was performed by amplification of a fragment of 871 bp in all tested isolates, using the primer pair CMVCPfwd/CPrev that amplify the entire coat protein gene and part of 5' and 3' UTR regions. The affiliation of Serbian CMV isolates from watermelon to subgroup IA, the group that includes most of the isolates selected for phylogenetic analysis, was determined by sequence analysis of the complete CP gene and reconstruction of phylogenetic tree.