Dynamics of a Mobile RNA of Potato Involved in a Long-Distance Signaling Pathway

• Published in: The Plant cell Vol. 18; no. 12; pp. 3443 - 3457
• Main Authors: Banerjee, Anjan K., Chatterjee, Mithu, Yu, Yueyue, Suh, Sang-Gon, Miller, W. Allen, Hannapel, David J.
• Format: Journal Article
• Language: English
• Published: England American Society of Plant Biologists 01.12.2006
• Subjects: Epidermal cells; Gene Expression Regulation, Plant - radiation effects; Glucuronidase - metabolism; Molecular Sequence Data; Open Reading Frames - genetics; Phloem; Phloem - cytology; Phloem - radiation effects; Photoperiod; Plant cells; Plant Leaves - metabolism; Plant Leaves - radiation effects; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Stems - cytology; Plant Stems - metabolism; Plant Stems - radiation effects; Plant Tubers - metabolism; Plant Tubers - radiation effects; Plants; Plants, Genetically Modified; Polymerase chain reaction; Potatoes; Promoter Regions, Genetic - genetics; RNA; RNA Transport - radiation effects; RNA, Plant - metabolism; Signal Transduction - radiation effects; Solanum tuberosum; Solanum tuberosum - genetics; Solanum tuberosum - metabolism; Solanum tuberosum - radiation effects; Stolons; Transgenic plants; Tubers; Untranslated regions; Untranslated Regions - metabolism
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.106.042473

BEL1-like transcription factors interact with Knotted1 types to regulate numerous developmental processes. In potato (Solanum tuberosum), the BEL1 transcription factor St BEL5 and its protein partner POTH1 regulate tuber formation by mediating hormone levels in the stolon tip. The accumulation of St BEL5 RNA increases in response to short-day photoperiods, inductive for tuber formation. RNA detection methods and heterografting experiments demonstrate that BEL5 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 RNA to stolon tips is correlated with enhanced tuber production. Overexpression of BEL5 transcripts that include the untranslated sequences of the BEL5 transcript endows transgenic lines with the capacity to overcome the inhibitory effects of long days on tuber formation. Addition of the untranslated regions leads to preferential accumulation of the BEL5 RNA in stolon tips under short-day conditions. Using a leaf-specific promoter, the movement of BEL5 RNA to stolon tips was facilitated by a short-day photoperiod, and this movement was correlated with enhanced tuber production. These results implicate the transcripts of St BEL5 in a long-distance signaling pathway that are delivered to the target organ via the phloem stream.