OUROBOROS is a master regulator of the gametophyte to sporophyte life cycle transition in the brown alga Ectocarpus

Proc Natl Acad Sci U S A. 2011 Jul 12;108(28):11518-23. doi: 10.1073/pnas.1102274108. Epub 2011 Jun 27.

Abstract

The brown alga Ectocarpus siliculosus has a haploid-diploid life cycle that involves an alternation between two distinct generations, the sporophyte and the gametophyte. We describe a mutant, ouroboros (oro), in which the sporophyte generation is converted into a functional, gamete-producing gametophyte. The life history of the mutant thus consists of a continuous reiteration of the gametophyte generation. The oro mutant exhibited morphological features typical of the gametophyte generation and accumulated transcripts of gametophyte generation marker genes. Genetic analysis showed that oro behaved as a single, recessive, Mendelian locus that was unlinked to the IMMEDIATE UPRIGHT locus, which has been shown to be necessary for full expression of the sporophyte developmental program. The data presented here indicate that ORO is a master regulator of the gametophyte-to-sporophyte life cycle transition and, moreover, that oro represents a unique class of homeotic mutation that results in switching between two developmental programs that operate at the level of the whole organism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Diploidy
  • Gene Expression Regulation, Developmental
  • Germ Cells, Plant / growth & development
  • Germ Cells, Plant / metabolism
  • Haploidy
  • Homozygote
  • Mutation
  • Oligonucleotide Array Sequence Analysis
  • Phaeophyceae / genetics
  • Phaeophyceae / growth & development*
  • Phaeophyceae / metabolism
  • Phenotype
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • RNA, Messenger