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Descripción
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| Plant growth and development is regulated in great parts by phytohormones, which are small signalling molecules of various chemical natures, acting at sub-micromolar concentrations. One of them is the plant hormone indole-3-acetic acid (IAA), considered as the most abundant naturally occurring auxin. IAA is controlling many aspects of plant development, e.g. cell division, apical dominance, senescence, etc. (Davies, 2004). Much is known about the physiology of auxin, however, how IAA is biosynthesized remains, at least in parts, unclear. There is evidence for different pathways involved in IAA production that work either in parallel or in a redundant manner. They are principally classified in two groups: Tryptophan independent- and dependent-pathways. In the latter group, we can find a number of different pathways. One of them, designated by its hallmark-intermediate, is called the IAM-pathway. Herein, indole-3-acetamide (IAM) is converted to IAA by the virtue of AMIDASE1 (AMI1) (Pollmann et al., 2003). However, so far, this conversion has only been demonstrated in vitro. Here, we provide in vivo-evidence that AMI1 is capable of influencing auxin contents by analysing different knock out (k.o.) mutants as well as inducible over-expressor lines for AMI1. Moreover, we investigated the distribution and the enzymatic properties of AMI1-like proteins in the plant kingdom, disclosing a widespread occurrence of AMI1-like proteins and very similar characteristics for the amidases studied. These results suggest a conserved and important role of this enzyme in plant development. In addition, comprehensive whole-genome wide transcriptomics analyses were used to characterize AMI1 functionally, comparing wild-type Arabidopsis, with ami1-2 and AMI1ind lines. In these enrichment assays, we found groups of genes involved in plant defense responses towards pathogen attacks and genes participating in related phytohormones-signalling pathways [e.g. the jasmonic acid (JA)], being overrepresented. For instance, in the ami1-2 mutant that contains increased IAM- and decreased IAA contents, we discovered an overexpression of several JA biosynthesis-associated genes. This induction of JA biosynthesis does not occur in AMI1ind, where IAM is effectively converted into IAA. This suggests an important role for AMI1 in maintaining the balance between IAM and IAA in plants. | |
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Internacional
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No |
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Nombre congreso
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XIII Reunión de Biología Molecular de Plantas |
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Tipo de participación
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970 |
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Lugar del congreso
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Oviedo |
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Revisores
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No |
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ISBN o ISSN
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0000-0000 |
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DOI
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Fecha inicio congreso
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22/06/2016 |
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Fecha fin congreso
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24/06/2016 |
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Desde la página
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112 |
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Hasta la página
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112 |
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Título de las actas
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Libro de resúmenes del congreso |