Abstract
The plant hormone brassinosteroid (BR) is known to affect a wide range of biological aspects,
here among promotion of plant growth. Since the discovery of this class of plant steroids in
the 1970s, BR has been a target when breeding for increased biomass production in plants. In
this PhD study two different approaches for targeting BRs, with the purpose of increasing
biomass, has been carried out.
The first approach was based on the so-called leaf-unrolling test and aimed at quantifying
brassinosteroid sensitivity in a collection of different wheat genotypes. However, a
combination of practical and technical reasons hampered the application of this method.
Instead, an alternative BR sensitivity assay was developed based on the effects synthetic BR
analogs have on root growth.
The second approach was based on the reverse genetics technique TILLING, a method to
identify mutations in specific genes. With TILLING, two mutants of selected BR-related genes
were identified in a Brachypodium distachyon mutant population. However, compared to the wild
type, the mutants did not produce more biomass.
The work with BR effects on plant root growth stimulated an interest for roots and root
development, which resulted in a one year stay in Professor Elison B. Blancaflors lab. During
this period, basic studies of BR effects on plant root development were carried out. As a
central finding, it was shown that BR affects the anti-gravity growth response of roots, the
autotropic straightening, through stabilization of filamentous actin.
Also basic studies of the root system architecture (RSA) of young wheat seedlings were
conducted in order to clarify the mechanisms behind the distinct growth angles of the three
first appearing embryogenic roots. Root system architecture of plants has gained major interest
in recent years, because it is found to be very important, not only for plant establishment, but
also for plant fitness and performance in different environments.
here among promotion of plant growth. Since the discovery of this class of plant steroids in
the 1970s, BR has been a target when breeding for increased biomass production in plants. In
this PhD study two different approaches for targeting BRs, with the purpose of increasing
biomass, has been carried out.
The first approach was based on the so-called leaf-unrolling test and aimed at quantifying
brassinosteroid sensitivity in a collection of different wheat genotypes. However, a
combination of practical and technical reasons hampered the application of this method.
Instead, an alternative BR sensitivity assay was developed based on the effects synthetic BR
analogs have on root growth.
The second approach was based on the reverse genetics technique TILLING, a method to
identify mutations in specific genes. With TILLING, two mutants of selected BR-related genes
were identified in a Brachypodium distachyon mutant population. However, compared to the wild
type, the mutants did not produce more biomass.
The work with BR effects on plant root growth stimulated an interest for roots and root
development, which resulted in a one year stay in Professor Elison B. Blancaflors lab. During
this period, basic studies of BR effects on plant root development were carried out. As a
central finding, it was shown that BR affects the anti-gravity growth response of roots, the
autotropic straightening, through stabilization of filamentous actin.
Also basic studies of the root system architecture (RSA) of young wheat seedlings were
conducted in order to clarify the mechanisms behind the distinct growth angles of the three
first appearing embryogenic roots. Root system architecture of plants has gained major interest
in recent years, because it is found to be very important, not only for plant establishment, but
also for plant fitness and performance in different environments.
| Original language | English |
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| Publisher | Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen |
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| Publication status | Published - 2016 |