A distinct strain of chickpea chlorotic dwarf virus (genus Mastrevirus, family Geminiviridae) identified in cotton plants affected by leaf curl disease

As part of a study to determine the diversity of whitefly-transmitted viruses (genus Begomovirus, family Geminiviridae) associated with cotton leaf curl disease in Pakistan, leaf samples from cotton plants showing typical leaf curl disease symptoms were collected in various locations of Punjab province. Sequence analysis of full-length virus clones (~2.7 kb) showed plants to be infected with the begomovirus cotton leaf curl Burewala virus, the only virus identified in cotton in the Punjab since 2001. Surprisingly, a second virus, the leafhopper-transmitted chickpea chlorotic dwarf virus (CpCDV) of the genus Mastrevirus (family Geminiviridae), was identified in a small number of plants. The sequences of four CpCDV isolates from cotton originating from geographically distinct areas in Punjab were obtained. Analysis of the sequences showed them to represent a distinct, newly identified strain of CpCDV with the highest levels of nucleotide sequence identity to isolates of CpCDV strains C and D that have been identified previously in Pakistan. CpCDV has not been identified previously in cotton. The significance of this finding is discussed.