Evolution of growth-promoting plant hormones

John J. Ross; James B. Reid

doi:10.1071/FP10063

EVOLUTIONARY REVIEW

Previous Next Contents Vol 37(9)

Evolution of growth-promoting plant hormones

John J. Ross ^A and James B. Reid ^A ^B

+ Author Affiliations

- Author Affiliations

^A School of Plant Science, University of Tasmania, Hobart, Tas. 7001, Australia.

^B Corresponding author. Email: jim.reid@utas.edu.au

This paper is part of an ongoing series: ‘The Evolution of Plant Functions’.

Functional Plant Biology 37(9) 795-805 https://doi.org/10.1071/FP10063
Submitted: 22 March 2010 Accepted: 14 May 2010 Published: 24 August 2010

Abstract

The plant growth hormones auxin, gibberellins (GAs) and brassinosteroids (BRs) are major determinants of plant growth and development. Recently, key signalling components for these hormones have been identified in vascular plants and, at least for the GAs and BRs, biosynthetic pathways have been clarified. The genome sequencing of a range of species, including a few non-flowering plants, has allowed insight into the evolution of the hormone systems. It appears that the moss Physcomitrella patens can respond to auxin and contains key elements of the auxin signalling pathway, although there is some doubt as to whether it shows a fully developed rapid auxin response. On the other hand, P. patens does not show a GA response, even though it contains genes for components of GA signalling. The GA response system appears to be more advanced in the lycophyte Selaginella moellendorffii than in P. patens. Signalling systems for BRs probably arose after the evolutionary divergence of the mosses and vascular plants, although detailed information is limited. Certainly, the processes affected by the growth hormones (e.g. GAs) can differ in the different plant groups, and there is evidence that with the evolution of the angiosperms, the hormone systems have become more complex at the gene level. The intermediate nature of mosses in terms of overall hormone biology allows us to speculate about the possible relationship between the evolution of plant growth hormones and the evolution of terrestrial vascular plants in general.

Additional keywords: auxin, brassinosteroid, gibberellin, moss.

Acknowledgements

We thank Drs Sandra Davidson and Gregory Jordan for critical comments on the manuscript, and the Australian Research Council for financial support.

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