Ghent, Belgium
November 9, 2008
Scientists from VIB at
Ghent University have
succeeded in converting annual plants into perennials. They
discovered that the deactivation of two genes in annuals led to
the formation of structures that converted the plant into a
perennial. This was most likely an important mechanism in plant
evolution, initiating the formation of trees.
Annuals and perennials
Annual crops
grow, blossom and die within one year. Perennials overwinter and
grow again the following year. The life strategy of many annuals
consists of rapid growth following germination and rapid
transition to flower and seed formation, thus preventing the
loss of energy needed to create permanent structures. They
germinate quickly after the winter so that they come out before
other plants, thus eliminating the need to compete for food and
light. The trick is basically to make as many seeds as possible
in as short a time as possible.
Perennials
have more evolved life strategies for surviving in poor
conditions. They compose perennial structures such as
overwintering buds, bulbs or tubers. These structures contain
groups with cells that are not yet specialised, but which can
later be converted when required into new organs such as stalks
and leaves.
The flowering of annuals
Annual crops
consume all the non-specialised cells in developing their
flowers. Thus the appearance of the flower signals means the end
of the plant. But fortunately they have left seeds that sense
after winter that the moment has come to start up. Plants are
able to register the lengthening of the days. With the advent of
longer days in the spring, a signal is sent from the leaves to
the growth tops to activate a limited number of
blooming-induction genes.
Deactivating
two genes
VIB researchers, such as
Siegbert Melzer
in
Tom Beeckman's
group*, have studied two such flower-inducing genes. They have
deactivated them in thale cress (Arabidopsis thaliana), a
typical annual. The VIB researchers found that mutant plants can
no longer induce flowering, but they can continue to grow
vegetatively or come into flower much later. Melzer had found
that modified crops did not use up their store of
non-specialised cells, enabling perennial growth. They can
therefore continue to grow for a very long time.
As with real
perennials these plants show secondary growth with wood
formation creating shrub-like Arabidopsis plants.
Raising the
veil of evolution
Researchers have
been fascinated for a long time by the evolution of herbaceous
to woody structures. This research clearly shows only two genes
are in fact necessary in this process. This has probably been
going on throughout the evolution of plants. Furthermore it is
not inconceivable this happened independently on multiple
occasions.
Relevant scientific publication
The research appears in the leading journal Nature Genetics
(Siegbert Melzer et al., Flowering-time genes modulate
meristem determinacy and growth form in Arabidopsis thaliana).
Funding
This research was financed by VIB, UGent, IWT, FWO.
* Tom Beeckman is in charge of the Root
Development research group in the VIB Plant Systems Biology
department, UGent under the management of Dirk Inzι.
VIB is a non-profit research institute in life sciences.
Approximately 1100 scientists and technicians perform basic
research into the molecular mechanisms that are responsible for
the functioning of the human body, plants and micro-organisms.
By means of a strong partnership with four Flemish universities
UGent, K.U.Leuven, Universiteit Antwerpen and Vrije
Universiteit Brussel and a robust investment programme, VIB
bundles the strengths of 65 research groups into one institute.
Their research aims at fundamentally pushing out the boundaries
of our knowledge. With its technology transfer activities VIB
aims to convert research results into products for the consumer
and the patient. VIB develops and disseminates a broad range of
scientifically based information on all aspects of
biotechnology. More information on
www.vib.be.
The Universiteit Gent (UGent) is one of the
largest Dutch-speaking universities, with more than 30,000
students. The
course options include almost all academic courses that are
offered in Flanders.
The UGent prides itself on being an open,
socially engaged and pluralistic university with an
international perspective. More information on
www.ugent.be |
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