Formula discovered
for longer plant life
Source: Max Planck Institute
September 25, 2008
CheckBiotech
Molecular biologists from Tübingen
have discovered how the growth of leaves and the aging process of plants are
coordinated
Plants that grow more
slowly stay fresh longer. In their study now published in PLoS
Biology, scientists at the Max Planck Institute for Developmental Biology in Tübingen have shown that certain small sections of genes,
so-called microRNAs, coordinate growth and aging
processes in plants. These microRNAs inhibit certain
regulators, known as TCP transcription factors. These transcription factors in
turn influence the production of jasmonic acid, a
plant hormone. The higher the number of microRNAs
present, the lower the number of transcription factors that are active, and the
smaller the amount of jasmonic acid, which is
produced by the plant. The plant therefore ages more slowly, as this hormone is
important for the plant’s aging processes.
The researchers have succeeded for the first time in
describing the antagonistic regulation of growth and aging in plants. Since the
quantity of microRNAs in the plants can be controlled
by genetic methods, it may be possible in future to cultivate plants that live
longer and grow faster.
MicroRNAs are short, single-strand
sections of genes that regulate other genes. They do this by binding to
complementary sections of the genetic material, thus preventing them from being
read and implemented in genetic products. In plants, microRNAs
mainly inhibit other regulators, so-called transcription factors. These factors
can switch genes on or off by binding to DNA sections, thus activating or
blocking them so that either too many or too few proteins are formed. Since
proteins control metabolic processes, an imbalance leads to more or less
clearly visible changes to the plant.
The scientists in Prof. Detlef Weigel’s department at the Max Planck Institute for
Developmental Biology have investigated the effects that the transcription
factors of the TCP family have on the growth and aging of the thale cress model plant (Arabidopsis thaliana). These
transcription factors are regulated by the microRNA
miR319.
It was already known that miR319-regulated transcription
factors affect the growth of leaves. Using a combination of biochemical and
genetic analyses, the researchers have now discovered that the transcription
factors also regulate those genes that are essential for the formation of the
plant hormone jasmonic acid. The higher the amount of
microRNA miR319 present in the plant, the lower the
number of transcription factors that are produced. This results in smaller
amounts of jasmonic acid which can be synthesized.
Plants containing little jasmonic acid age more
slowly: The leaves become yellow and the plant dies. This process can be
stopped by treating the plant with the hormone.
"Our studies show that the transcription factors, which
are regulated by the microRNA miR319, exert a
negative influence on the growth of plants, and also lead to premature aging.
The mechanism discovered here is a further milestone in the attempt to explain
the relationships of genetic regulation in plants. Only when we have a better
understanding of these processes will we be able to produce plants that have
particularly desired properties," says Detlef Weigel, who heads the project.
About the Max Planck Institute
The Max Planck Institute for Developmental Biology conducts
basic research in the areas of biochemistry, genetics and evolutionary biology.
It has some 325 employees and is located at the Max Planck campus in
Original work:
Schommer, C., Palatnik,
J.F., Aggarwal, P., Chételat,
A.,
Control of Jasmonate
Biosynthesis and Senescence by miR319 Targets.
PLoS Biology, doi:10.1371/journal.pbio.0060230
CONTACT:
Prof. Dr. Detlef Weigel
Max Planck Institute for Developmental Biology, Tübingen
Tel.: +49 7071 601-1410
E-mail: Detlef.Weigel@tuebingen.mpg.de
Dr. Susanne Diederich (Press and
PR Department)
Max Planck Institute for Developmental Biology, Tübingen
Tel.: +49 7071 601-333
E-mail: presse@tuebingen.mpg.de
Source: Max Planck Institute
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