Figure 7. Southern hybridization of cotton leaf DNA with riboprobes transcribed from pCLCrVU (panel A) and pCLCuV (panel B). Total DNA was extracted from cotton leaf crumple virus-infected leaves (lanes 1 and 2), cotton leaf curl virus-infected (lanes 3 and 4), and healthy leaves (lanes 5 and 6). DNA samples were either digested with EcoRV (Lanes 2, 4, and 6) or undigested (lanes 1, 3, and 5) prior to electrophoresis in a 0.8% agarose gel. DNA immobilized on the nylon membrane was hybridized with 32P-labelled riboprobes complementary to the geminivirus virion-sense, single-stranded DNA and autoradiographed. Replicative forms (RF) of the geminivirus DNA A were clearly visible in samples digested with EcoRV (lanes 2, panel A, and lane 4, panel B). A single species of subgenomic DNA (sg DNA) was detected in DNA from CLCuV-infected samples (lanes 3 and 4, panel B) below the single-stranded genomic DNA A (ssDNA). Positions of DNA standard (1 kb DNA ladder, BRL) are labelled to the right of the autoradiograph.