Genome Characterisation and Pathogenicity Analysis of Iranian Isolates of Okra Enation Leaf Curl Virus (Begomovirus abelsmoschusenation) and Their Associated Satellites

Begomoviruses and associated betasatellite molecules significantly impact crop yields in Middle Eastern countries. Previously, cotton leaf curl Gezira virus (CLCuGeV, Begomovirus gossypigeziraense) and the associated betasatellite, okra leaf curl Oman betasatellite (OLCuOMB, Betasatellite abelmoschusomanense), were detected in okra farms in Jiroft, south-eastern Iran. The current study describes the interaction between OLCuOMB and okra leaf curl enation virus (OELCuV, Begomovirus abelsmoschusenation) in okra farms in the same region. Both OELCuV and OLCuOMB, along with the Gossypium darwinii symptomless alphasatellite (GDarSLA, Colecusatellite gossypiumdarwinii), were detected in okra plants, and a similar viral association with only GDarSLA was found in diseased basil plants. The full-length genomes of OELCuV isolates from okra and basil shared 99.4% nucleotide identity with each other, and > 97% with other Iranian isolates from papaya available in GenBank. To satisfy Koch's postulates, an infectious clone of OELCuV was constructed, and its pathogenicity was assessed with or without the OLCuOMB clone. Accordingly, agroinoculation with a combination of OELCuV and OLCuOMB resulted in more severe symptoms in okra plants compared to the milder symptoms produced following agroinoculation with the virus alone. The presence of alphasatellite and betasatellite molecules in association with various begomoviruses, and a turncurtovirus across different crops in south-eastern Iran indicates that geminivirus-satellite disease complexes are causing significant yield losses in this region.