Plant biology

Mobile mRNA Makes Potatoes

Science's STKE  13 Feb 2007:
Vol. 2007, Issue 373, pp. tw50
DOI: 10.1126/stke.3732007tw50

Tuber formation in potato plants is promoted when plants are exposed to short-day photoperiods and inhibited in plants that experience summerlike long periods of daylight. This process requires that a signal be passed from the leaves to the growing tuber underground. Banerjee et al. report a series of experiments that implicate specific mRNAs as the molecules that carry the signal. The mRNA encodes a transcription factor called St BEL5 that acts with another transcription factor, POTH1, to control hormone concentrations in the tuber that regulate growth. The authors used laser microdissection of specific cell types and reverse transcription polymerase chain reaction amplification to pinpoint specific mRNAs in phloem and other cell types. When a leaf-specific promoter was used to drive expression of St BEL5 RNA, exposure to short days enhanced mobility of the RNA to the root region. Overexpression of the St BEL5 transcript enabled transgenic plants to undertake tuber formation even when exposed to long photoperiods. The authors propose that the mRNA transport reflects light-dependent changes in the abundance of RNA-binding proteins that facilitate transport and targeting of mRNA to specific cells.

A. K. Banerjee, M. Chatterjee, Y. Yu, S.-G. Suh, W. A. Miller, D. J. Hannapel, Dynamics of a mobile RNA of potato involved in a long-distance signaling pathway. Plant Cell 18, 3443-3457 (2006). [Abstract] [Full Text]