SEQUENCE AND PHYLOGENETIC ANALYSIS OF THE CYTOPLASMIC INCLUSION PROTEIN GENE OF ZUCCHINI YELLOW MOSAIC POTYVIRUS - ITS ROLE IN CLASSIFICATION OF THE POTYVIRIDAE

The cytoplasmic inclusion (CI) gene of a Singapore isolate of zucchini yellow mosaic virus (ZYMV-S) was sequenced and compared with CI of 14 other potyviruses. In addition to the consensus sequence GAVGSGKST of nucleotide binding motif (NTBM) which is implicated as a membrane-bin ding component of the RNA helicase complex, five other conserved motif s were found. Phylogenetic trees were constructed from sequence data f or the CI and the coat protein. Similar branching patterns obtained fr om both CI and coat protein analyses suggests that phylogenetic relati onship among polyviruses can be determined using the CI. We propose th at phylogenetic analysis of CI gene may be used as an alternative appr oach for the study of evolution within the family Polyviridae.