INFECTIVITY AND COMPLETE NUCLEOTIDE-SEQUENCE OF THE CLONED GENOMIC COMPONENTS OF A BIPARTITE SQUASH LEAF CURL GEMINIVIRUS WITH A BROAD HOST RANGE PHENOTYPE

Through cloning and molecular analysis we have identified two highly homologous bipartite geminiviruses as causing squash leaf curl disease. Mechanical and Agrobacterium-mediated inoculation of plants with cloned viral DNA components identified the two genomic components of SqLCV-E, a squash leaf curl virus with an unexpectedly broad host range for a whitefly-transmitted geminivirus. Nucleotide sequence analysis of the genome of this virus showed it to have the same bipartite component organization characteristic of other whitefly-transmitted geminiviruses. Sequence comparison with the genomic components of tomato golden mosaic virus and bean golden mosaic virus revealed a close evolutionary relationship with these two bipartite geminiviruses, with which SgLCV-E shares common hosts. These studies provide clear molecular evidence for the assignment of SqLCV to the subfamily of bipartite geminiviruses. © 1991.