Prof. David J. Hannapel from Iowa State University, USA, will give a short lecture called “A full-length mobile mRNA of potato acts a long-distance signal in development” at 2 pm on the 11th of January. The lecture will be held in the seminar room of the Department of Experimental Plant Biology, Viničná 5, 2nd floor.
BEL1-like transcription factors are ubiquitous in plants and interact with KNOTTED1-types to regulate numerous developmental processes. In potato, the BEL1-like transcription factor, StBEL5, and its KNOX protein partner regulate tuber formation by targeting genes that control growth. Transgenic over-expression of StBEL5 resulted in plants that consistently exhibited enhanced tuber yields. RNA detection methods and heterografting experiments demonstrated that StBEL5 transcripts are present in phloem cells and move across a graft union to localize in stolon tips, the site of tuber induction. This movement of the full-length mRNA originates in leaf veins and petioles and is induced by a short-day photoperiod, regulated by the untranslated regions, and correlated with enhanced tuber production. StBEL5 RNA also moves into roots to enhance root growth. At the site of BEL5 activity in stolon tips and roots, in a remarkable auto-regulatory process, the StBEL5 protein, in tandem with its KNOX partner, activates its own promoter to enhance the tuberization signal. Auto-regulation of the StBEL5 promoter in stolons and roots may be controlled by transcript mobility. Transport of mobile RNAs is mediated by select RNA-binding proteins that act as chaperones to regulate translation and facilitate delivery. Using RNA/protein affinity assays, several RNA-binding proteins are being studied to determine their role in mediating the transport of the mobile StBEL5 mRNA. Figure.