Long-distance movement of Arabidopsis FLOWERING LOCUS T RNA participates in systemic floral regulation

RNA Biol. 2012 May;9(5):653-62. doi: 10.4161/rna.19965. Epub 2012 May 1.

Abstract

The finding of mRNA acting as a systemic information molecule is one of the most exciting discoveries in recent plant biology. However, evidence demonstrating the functional significance of non-cell autonomous RNA remains limited. Recent analyses of Arabidopsis and rice revealed FLOWERING LOCUS T (FT) protein as a systemic florigenic signal. However, whether the FT RNA also participates in systemic floral regulation remains controversial. By using Arabidopsis cleft-grafting experiments, we showed that the RNA of Arabidopsis FT undergoes long-distance movement from the stock to the scion apex in both FT transformants and non-transformants. In addition, the sequences of FT RNA are sufficient to target a cell-autonomous RNA for long-distance movement. Therefore, FT RNA is a bona fide non-cell autonomous RNA. To examine the systemic action of FT RNA, we uncoupled the movement of FT RNA from protein by fusing FT with RED FLUORESCENT PROTEIN (RFP). When RFP-FT protein was retained in companion cells, the detection of RFP-FT RNA correlates with floral promotion in the scion. Further depletion of the translocated RFP-FT RNA by RNAi or artificial miRNA against FT delayed the floral promotion, indicating that the translocated FT RNA acts as a part of the systemic floral signaling. Our results indicate that both FT RNA and protein move long distance and act redundantly to integrate the photoperiodic signals.

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis / growth & development
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Arabidopsis Proteins / physiology
  • Flowers / genetics*
  • Flowers / growth & development
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Intercellular Signaling Peptides and Proteins / physiology
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Photoperiod
  • Plants, Genetically Modified
  • RNA Transport
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • RNA, Messenger / physiology
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • RNA, Plant / physiology
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Red Fluorescent Protein
  • Seedlings / genetics
  • Seedlings / growth & development

Substances

  • Arabidopsis Proteins
  • FT protein, Arabidopsis
  • Intercellular Signaling Peptides and Proteins
  • Luminescent Proteins
  • RNA, Messenger
  • RNA, Plant
  • Recombinant Fusion Proteins