Physcomitrella patens: A Model Bryophyte

Abstract

Physcomitrella patens is a species of moss that has been studied experimentally for over half a century. The techniques that have been developed for the study of this model organism allow us to answer biological questions relating to plant growth and development, adaptation to environments and plant evolution. The recent completion of the P. patens genome sequence as the first non‐angiosperm land plant allows comparative genomic analyses and identification of conserved genes as well as genes with novel functions. P. patens has a special feature among plants, that of an efficient gene‐targeting mechanism, enabling gene functions to be identified by targeted mutations. Such comparative and experimental approaches allowed the determination of similarities and differences between mosses and angiosperms in their response to light and hormones. Finally, we may be able to learn how plants deal with environmental stresses by studying these processes in P. patens.

Key concepts:

  • P. patens is a model organism because it can be studied simply within a controlled environment to address biological questions.

  • P. patens is easy to culture in vitro because the cells are totipotent.

  • P. patens undergoes highly efficient gene targeting that allows in vivo analysis of a gene's function by mutating the endogenous gene after introduction of a cloned homologue.

  • It is easy to identify mutant phenotypes in P. patens because the gametophytic cells are haploid.

  • P. patens is the first nonangiosperm land plant to have its genome sequence published.

  • Genomic comparisons and other studies suggest that there are many similarities in the ways in which mosses and angiosperms use environmental cues to develop, indicating conserved evolution; however, mosses also possess some unique sequences which might present novel gene functions.

Keywords: model organism; genome sequence; environmental stress; hormones; gene targeting

Figure 1.

The gametophyte and sporophyte of Physcomitrella patens. Light micrographs of leafy gametophores, comprising the gametophyte. A single immature sporophyte is visible, developing at the apex of a gametophore. Reproduced from Knight et al. (2009) with permission from Wiley‐Blackwell.

Figure 2.

A simplified scheme for moss gametophyte development indicating the morphogenetic actions of the plant hormones abscisic acid (ABA), auxin (IAA) and cytokinin (CK), ‘+’ promoting effect, ‘−’ inhibiting effect. Scale bars correspond to 50 μm in (a) to (f), to 350 μm in (g) and (h) and to 150 μm in (i). Reproduced from Knight et al. (2009) and Decker et al. (2006) with permission from Wiley‐Blackwell.

Figure 3.

ABA‐induced morphological changes in P. patens protonemata. Scanning‐electron microscope images of P. patens protonemata untreated (a) and after treatment with 100 μM ABA (b and c). ABA‐treated moss cells differentiate into chains of brachycytes (b) or brachycytes flanked by tmema cells (c). Bars correspond to 30 μm. Reproduced from Knight et al. (2009) and Decker et al. (2006) with permission from Wiley‐Blackwell.

close

Further Reading

Charron AJ and Quatrano RS (2009) Between a rock and a dry place: the water‐stressed moss. Molecular Plant 2: 478–486.

Cosmoss: http://www.cosmoss.org (Accessed in January 2010).

Gitzinger M, Parsons J, Reski R and Fussenegger M (2009) Functional cross‐kingdom conservation of mammalian and moss (Physcomitrella patens) transcription, translation and secretion machineries. Plant Biotechnology Journal 7: 73–86.

Knight CD, Perroud P‐F and Cove DJ (2009) The moss Physcomitrella patens. Annual Plant Reviews 36: 1–349.

Lamparter T (2006) Photomorphogenesis of mosses. In: Schäfer E and Nagy F (eds) Photomorphogenesis in Plants and Bacteria, 3rd edn. Stuttgart, Germany: Springer.

Lucumi A and Posten C (2006) Establishment of long‐term perfusion cultures of recombinant moss in a pilot tubular photobioreactor. Process Biochemistry 41: 2180–2187.

Menand B, Yi K, Jouannic S et al. (2007) An ancient mechanism controls the development of cells with a rooting function in land plants. Science 316: 1477. DOI: 10.1126/science.1142618

Physcobase: http://moss.nibb.ac.jp/ (Accessed in January 2010).

Rensing SA, Lang D, Zimmer AD et al. (2008) The Physcomitrella genome reveals evolutionary insights into the conquest of land by plants. Science 319: 64–69.

Schween G, Egener T, Fritzowsky D et al. (2005) Large‐scale analysis of 73 329 Physcomitrella plants transformed with different gene disruption libraries: production parameters and mutant phenotypes. Plant Biology (Stuttgart, Germany) 7(3): 228–237.

Shaw AJ and Goffinet B (eds) (2000) Bryophyte Biology. Cambridge, UK: Cambridge University Press.

The Moss Genome homepage: http://www.mossgenome.org (Accessed in January 2010).

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Knight, Celia D, and Perroud, Pierre‐François(Apr 2010) Physcomitrella patens: A Model Bryophyte. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0003678]