Alternation of generations - unravelling the underlying molecular mechanism of a 165-year-old botanical observation.
Characteristically, land plants exhibit a life cycle with an 'alternation of generations' and thus alternate between a haploid gametophyte and a diploid sporophyte. At meiosis and fertilisation the transitions between these two ontogenies take place in distinct single stem cells. The evolutionary invention of an embryo, and thus an upright multicellular sporophyte, in the ancestor of land plants formed the basis for the evolution of increasingly complex plant morphologies shaping Earth's ecosystems. Recent research employing the moss Physcomitrella patens revealed the homeotic gene BELL1 as a master regulator of the gametophyte-to-sporophyte transition. Here, we discuss these findings in the context of classical botanical observations.
Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.
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Horst
Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.|BIOSS - Centre for Biological Signalling Studies, Freiburg, Germany.
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Reski
D000818:Animals; D019068:Bryopsida / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D004171:Diploidy; D019143:Evolution, Molecular; D055993:Germ Cells, Plant; D006238:Haploidy; D008018:Life Cycle Stages; D008540:Meiosis; D008958:Models, Molecular; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D012098:Reproduction; D012100:Reproduction, Asexual
D010940:Plant Proteins
Apogamy; Generationswechsel; Physcomitrella patens; Polycomb complex; apospory; epigenetics; homeodomain transcription factors