Polypyrimidine tract-binding proteins of potato mediate tuberization through an interaction withStBEL5RNA

Abstract

HighlightPTB proteins of potato bind to the mobile RNA, StBEL5, and enhance stability and trafficking of the RNA to select organs. This protein–RNA interaction leads to enhanced tuber production.

The Multiple Signals That Control Tuber Formation

“…In this way, the movement of StBEL5 RNA is induced by SD and the presence of its 39 UTR. Long-distance transport of StBEL5 mRNA has been verified using RNA movement assays in both whole plants and heterografts (Banerjee et al, 2006(Banerjee et al, , 2009Lin et al, 2013;Cho et al, 2015). Movement through the phloem also has been confirmed for a BEL5-like transcript in Arabidopsis (Notaguchi et al, 2015).…”

“…For example, tuber formation is additionally regulated by SD activation of the StPTB proteins (Cho et al, 2015). This activation enhances the stability and transport of StBEL5 transcript, directing this signal RNA to stolon tips.…”

“…These results reinforce the biological significance of the StPTB RNA-binding proteins and their role in enhancing StBEL5 activity. Even when StBEL5 RNA levels increased indirectly due to a relative increase in StPTB activity, tuber yields of soil-grown plants were enhanced approximately 2-fold (Cho et al, 2015).…”

“…Its expression is stimulated in leaves by low levels of blue and red light but not by daylength. The movement, stability, and localization of the StBEL5 RNA are controlled by two RNA-binding proteins from the polypyrimidine tract-binding (PTB) family of proteins, designated StPTB1 and StPTB6 (Cho et al, 2015). These RNA-binding proteins bind to a CU-rich sequence present in the 39 untranslated region (UTR) of the StBEL5 transcript, and their activity is enhanced by conditions favorable for tuber formation.…”

“…There are numerous documented examples of StBEL5's effect on tuberization in both a commercial cultivar and the photoperiod-responsive subspecies andigena (Chen et al, 2003;Banerjee et al, 2006Banerjee et al, , 2009Cho et al, 2015). Overexpression and enhanced accumulation led to early, increased tuberization, whereas RNA interference suppression of StBEL5 significantly reduced tuber yields in several independent lines (Sharma et al, 2016).…”