Exploring the methylation status of selected flowering genes in healthy and phyllody infected sesame plants

Phytoplasmas, plant pathogenic Mollicutes are associated with retrograde metamorphosis in phyllody affected sesame plants showing reversion of flowering shoots to leaf-like structures. The molecular mechanism responsible for these dramatic alterations has become an active research area. Recently, the role of phytoplasma secreted effector molecules in the disruption of normal activities of genes comprising floral quartet model has been suggested. However, the mechanism delineating the precise level at which interference of the normal gene expression is caused is far from being understood. DNA methylation is an epigenetic phenomenon that plays a significant role in altering the plant genome machinery in the presence of abiotic and biotic stresses including bacterial infections. The cytosine methylation status of selected key regulatory genes namely UNUSUAL FLORAL ORGANS (UFO), FLORICAULA/LFY (FLO), FLOWERING LOCUS T- like (FLT) and SUPERMAN (SUP), involved in flower development, were chosen for investigating their cytosine methylation status using the McrBC assay. Genic regions located in the sesame orthologs of the selected genes were identified for the primer design. Expected amplicons were obtained in healthy and phyllody infected sesame plants that did not reveal differential methylation. Nevertheless, considering the constraints of the McrBC assay in detecting the methylation, the need for comprehensive studies targeting more genes and higher coverage of the putative methylated regions is suggested before ruling out the involvement of epigenetic manipulation by phytoplasmas.