Phyllotactic regularity requires the Paf1 complex in Arabidopsis

Development. 2017 Dec 1;144(23):4428-4436. doi: 10.1242/dev.154369. Epub 2017 Oct 5.

Abstract

In plants, aerial organs are initiated at stereotyped intervals, both spatially (every 137° in a pattern called phyllotaxis) and temporally (at prescribed time intervals called plastochrons). To investigate the molecular basis of such regularity, mutants with altered architecture have been isolated. However, most of them only exhibit plastochron defects and/or produce a new, albeit equally reproducible, phyllotactic pattern. This leaves open the question of a molecular control of phyllotaxis regularity. Here, we show that phyllotaxis regularity depends on the function of VIP proteins, components of the RNA polymerase II-associated factor 1 complex (Paf1c). Divergence angles between successive organs along the stem exhibited increased variance in vip3-1 and vip3-2 compared with the wild type, in two different growth conditions. Similar results were obtained with the weak vip3-6 allele and in vip6, a mutant for another Paf1c subunit. Mathematical analysis confirmed that these defects could not be explained solely by plastochron defects. Instead, increased variance in phyllotaxis in vip3 was observed at the meristem and related to defects in spatial patterns of auxin activity. Thus, the regularity of spatial, auxin-dependent, patterning at the meristem requires Paf1c.

Keywords: Auxin; Meristem; Paf1c; Phyllotaxis; Reproducibility; Variability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / physiology*
  • Cotyledon / growth & development
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology
  • Genes, Plant
  • Indoleacetic Acids / metabolism
  • Meristem / growth & development
  • Mutation
  • Plant Development / genetics
  • Plant Development / physiology
  • Plants, Genetically Modified
  • Transcription Factors / genetics
  • Transcription Factors / physiology

Substances

  • Arabidopsis Proteins
  • DNA-Binding Proteins
  • Indoleacetic Acids
  • MONOPTEROS protein, Arabidopsis
  • SKI8 protein, Arabidopsis
  • Transcription Factors