Norwich, United Kingdom
July 12, 2007
A team of
John Innes Centre scientists
lead by Professor Nick Harberd have discovered how plants
evolved the ability to adapt to changes in climate and
environment. Plants adapt their growth, including key steps in
their life cycle such as germination and flowering, to take
advantage of environmental conditions. They can also repress
growth when their environment is not favourable. This involves
many complex signalling pathways which are integrated by the
plant growth hormone gibberellin.
Publishing in the journal
Current Biology,
the researchers looked at how plants evolved this ability by
looking at the genes involved in the gibberellin signalling
pathway in a wide range of plants. They discovered that it was
not until the flowering plants evolved 300 million years ago
that plants gained the ability to repress growth in response to
environmental cues.
All land plants evolved from an aquatic ancestor, and it was
after colonisation of the land that the gibberellin mechanism
evolved. The earliest land plants to evolve were the bryophyte
group, which includes liverworts, hornworts and ancestral
mosses, many of which still exist today. The ancestral mosses
have their own copies of the genes, but the proteins they make
do not interact with each other and can’t repress growth.
However, the moss proteins work the same as their more recently
evolved counterparts when transferred into modern flowering
plants.
The lycophyte group, which evolved 400 million years ago, were
the first plants to evolve vascular tissues - specialized
tissues for transporting water and nutrients through the plant.
This group of plants also have the genes involved in the
gibberellin signalling mechanism, and the products of their
genes are able to interact with each other, and the hormone
gibberellin. However this still does not result in growth
repression. Not until the evolution of the gymnosperms
(flowering plants) 300 million years ago are these interacting
proteins able to repress growth. This group of plants became the
most dominant, and make up the majority of plant species we see
today.
Evolution of this growth control mechanism appears to have
happened in a series of steps, which this study is able to
associate with major stages in the evolution of today’s
flowering plants. It also involves two types of evolutionary
change. As well as structural changes that allow the proteins to
interact, flowering plants have also changed the range of genes
that are turned on and off in response to these proteins. This
work was supported by the Biotechnology and Biological Sciences
Research Council.
This research will be published in Current Biology on 19 July
2007, and online ahead of the print issue on 12 June 2007
http://www.current-biology.com/
Step-by-Step Acquisition of the Gibberellin-DELLA
Growth-Regulatory Mechanism During Land-Plant Evolution.
Yuki Yasumura, Matilda Crumpton-Taylor, Sara Fuentes, and
Nicholas P. Harberd
Current Biology 17, 1225-1230, July 17, 2007 DOI
10.1016/j.cub.2007.06.037
The John Innes Centre, Norwich, UK is an independent,
world-leading research centre in plant and microbial sciences
with over 800 staff. JIC is based on Norwich Research Park and
carries out high quality fundamental, strategic and applied
research to understand how plants and microbes work at the
molecular, cellular and genetic levels. The JIC also trains
scientists and students, collaborates with many other research
laboratories and communicates its science to end-users and the
general public. The JIC is grant-aided by the Biotechnology and
Biological Sciences Research Council.
http://www.jic.ac.uk/
The Biotechnology and Biological Sciences Research Council
(BBSRC) is the UK funding agency for research in the life
sciences. Sponsored by Government, BBSRC annually invests around
£336 million in a wide range of research that makes a
significant contribution to the quality of life for UK citizens
and supports a number of important industrial stakeholders
including the agriculture, food, chemical, healthcare and
pharmaceutical sectors.
http://www.bbsrc.ac.uk |
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