Current Biology
Volume 23, Issue 11, 3 June 2013, Pages 956-962
Journal home page for Current Biology

Article
Phyllotaxis and Rhizotaxis in Arabidopsis Are Modified by Three PLETHORA Transcription Factors

https://doi.org/10.1016/j.cub.2013.04.048Get rights and content
Under an Elsevier user license
open archive

Highlights

  • PLT3, PLT5, and PLT7 genes control rhizotaxis by preventing LRP clustering

  • Root, but not shoot, expression of PLT genes is required for normal rhizotaxis

  • Three identical transcription factors influence rhizotaxis and phyllotaxis

  • PLT3, PLT5, and PLT7 act downstream of auxin-responsive ARF7 and ARF19 genes

Summary

Background

The juxtaposition of newly formed primordia in the root and shoot differs greatly, but their formation in both contexts depends on local accumulation of the signaling molecule auxin. Whether the spacing of lateral roots along the main root and the arrangement of leaf primordia at the plant apex are controlled by related underlying mechanisms has remained unclear.

Results

Here, we show that, in Arabidopsis thaliana, three transcriptional regulators implicated in phyllotaxis, PLETHORA3 (PLT3), PLT5, and PLT7, are expressed in incipient lateral root primordia where they are required for primordium development and lateral root emergence. Furthermore, all three PLT proteins prevent the formation of primordia close to one another, because, in their absence, successive lateral root primordia are frequently grouped in close longitudinal or radial clusters. The triple plt mutant phenotype is rescued by PLT-vYFP fusion proteins, which are expressed in the shoot meristem as well as the root, but not by expression of PLT7 in the shoot alone. Expression of all three PLT genes requires auxin response factors ARF7 and ARF19, and the reintroduction of PLT activity suffices to rescue lateral root formation in arf7,arf19.

Conclusions

Intriguingly PLT 3, PLT5, and PLT7 not only control the positioning of organs at the shoot meristem but also in the root; a striking observation that raises many evolutionary questions.

Cited by (0)

3

Present address: Plant Developmental Biology Group, Wageningen University Research, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands

4

These authors contributed equally to this work