Roye, Marcia E.; Mclaughlin,Wayne A.; Maxwell, D. P.
Author Affiliation, Ana.
The evolution of new virus genes: Interspecies recombination among two geminiviruses from Jamaica
Jamaican Journal of Science and Technology
Date of Publication
In 1994 a geminivirus was detected in cabbage from Jamaica by DNA hybridization and polymerase chain reaction (PCR). In 1997 several full-length clones of the cabbage virus were obtained from symptomatic cabbage plants from Jamaica. Nucleotide sequence analysis using DNASTAR showed that one DNA-A (CRFA 13) and one DNA-B (CRFB2) clone of the Jamaican cabbage virus were both >96% identical to cabbage leaf curl virus from Florida (CLCV-FL, GenBank no. U65529, U65530). The clones CRFA13 and CRFB2 were infectitious in Nicotiania benthmiana. These results together indicate that CLCV-FL was infecting cabbage plants in Jamaica. Nucleotide sequence of a second DNA-A clone (CRFA4) showed that a section of approximately 1600 nucleotides, which includes the entire avl, ac2, and ac3 genes and the c-terminal part of the acl gene was >93% identical to CLCV-FL. The remaining 1000 nucleotides were <70% similar to CLCV_FL and showed greatest nucleotide identity (86%) to macroptilium golden mosaic geminivirus (MacGMV-JM1, GenBank no. AF09840) which infects Macroptilium lathyroides a common leguminous weed in Jamaica. Further nucleotide sequence analysis showed that CRFA4 represents a recombianat geminivirus species with partial sequence identify to both CLCV-FL and MacMGV-JM1. This new virus species could have a host range and pathogenicity distinct from both CLCV-FL and MacMGV-JM1 the geminiviruses from which CRFA4 evolved. Recombination among geminiviruses is a recently reported phenomenon and often results in the evolution of new virus species similar to many RNA viruses where viral recombination has been shown to be a major evolutionary tool among these viruses. Recombinant virus species are of particular importance to scientists developing virus resistant plants genetically engineered with wild type or mutant viral genes. Recombination among viral species could easily result in the evolution of new viral genes and new viruses, which may break the resistance in these genetically engineered resistant plants. ....