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Cotton leaf curl disease (CLCuD) is a major constraint in the production of cotton crop across the Africa and Asia which is caused by a complex of begomoviruses (family Geminiviridae). Cotton leaf curl Khokhran virus and associated Cotton leaf curl Multan betasatellite (CLCuKoV/CLCuMB) complex are important agents of CLCuD which transmitted by whiteflies of the Bemisia tabaci species complex. Information regarding the transmission efficiency of CLCuKoV/CLCuMB by whitefly cryptic species is seriously lacking in Pakistan, therefore present study is conducted for comparison of transmission efficiency of CLCuKoV/CLCuMB by two characterized whitefly cryptic species (Asia II-1 and Asia II-5). Whitefly cryptic species were reared separately on Nicotiana benthamiana plants infected with CLCuKoV/CLCuMB for 24 or 48 h and these infected whitefly cryptic species were transferred to un-infected cotton and alternative host plants for 24 or 48 h. The first experiment results showed that Asia II-1 was able to transmit CLCuKoV/CLCuMB with high efficiency in cotton and bitter gourd plants as compared to the Asia II-5 while other host plants did not develop symptoms. Further in the second experiment results revealed that Asia II-1 was able to transmit CLCuKoV/CLCuMB with high efficiency from symptomatic bitter gourd to cotton plants as compared to Asia II-5 which did not show symptoms of transmission. Infection symptoms were confirmed by visual inspection after 30 days and PCR analysis. We found the percentage of virus infection symptoms in alternate host plants differed between two whitefly cryptic species due to varying transmission efficiencies. This research finding advances our understanding to explore the whitefly cryptic species involved in the transmission of CLCuD and will aid in the development of management strategies for control of whitefly cryptic species and CLCuD transmission in Pakistan. [ABSTRACT FROM AUTHOR]

Background: Bhendi or okra (Abelmoschus esculentus) is an important crop widely cultivated in the Indian subcontinent. The production of okra in tropical regions is constrained by several abiotic and biotic factors. Among biotic stresses, yellow vein mosaic disease (YVMD), transmitted by the whitefly (Bemisia tabaci Genn.), causes significant production losses. Results: Leaves showing symptoms of YVMD were collected from okra plants in the district of Mardan, Pakistan, from which the total nucleic acid was extracted. It was found that the viral genome was 2739 bp in the length and had seven conserved open reading frames, comparable to those of monopartite begomovirus species from the Old World. Nucleotide sequence comparison revealed that the genome has 97.7% identity with bhendi yellow vein mosaic virus (BYVMV). Additionally, alpha- and betasatellite DNA components were amplified and sequenced. The alpha- and betasatellite DNA sequences were 1367 and 1346 nt in length, respectively. Sequence analysis revealed that the alpha- and betasatellite sequences shared 97.9 and 98.7% similarity with cotton leaf curl Multan alphasatellite DNA (CLCuMuA) and croton yellow vein mosaic betasatellite DNA (CroYVMB), respectively. Conclusions: Based on the prevailing classification system, the isolate was identified as a variant of BYVMV, CLCuMuA, and CroYVB. Alphasatellite presence in the begomovirus betasatellite complex detected in the present study indicated a recent mobilization into the viral complex infecting okra in this region. The study findings may facilitate the design of new management strategies to protect this valuable crop against begomovirus infection. [ABSTRACT FROM AUTHOR]