Abstract
Plants have developed astonishing networks regulating their metabolism to adapt to their environment. The complexity of these networks is illustrated by the expansion of families of regulators such as transcription factors in the plant kingdom. Transcription factors specifically impact transcriptional networks by integrating exogenous and endogenous stimuli and regulating gene expression accordingly. Regulation of transcription factors and their activation is thus highly important to modulate the transcriptional programs and increase fitness of the plant in a given environment. Plant metabolism is regulated to allocate resources to growth and/or defense at different time points. Among plant chemical defenses are the amino acid-derived glucosinolates (GLS). Their absolute and relative accumulation is tightly regulated at basal level, but also in response to e.g. pathogen attack and hormone stimuli. The biosynthetic machinery of GLS is governed by interplay of six MYB and three bHLH transcription factors. MYB28, MYB29 and MYB76 regulate methionine-derived GLS, and MYB51, MYB34 and MYB122 regulate tryptophan-derived GLS. The three bHLH transcription factors MYC2, MYC3 and MYC4 physically interact with all six MYBs to activate transcription of GLS biosynthetic genes.
A lot is known about transcriptional regulation of these nine GLS regulators. This thesis aimed at identifying regulatory mechanisms at the protein level, allowing rapid and specific regulation of transcription factors using GLS as a model. The general introduction and the first chapter provide background on protein level regulation and underline the importance of these mechanisms in regulating transcription factors. The remaining chapters report the identification of multiple new regulators of MYB transcription factors, potentially involved in their regulation at multiple steps of their activation. Plant signaling in connection with transcription factor regulation is an exciting field, allowing research on multiple regulatory mechanisms. This thesis shed light on the importance of integrating all steps of transcription factor activation in a regulatory network in deciphering the complexity of plant responses.
A lot is known about transcriptional regulation of these nine GLS regulators. This thesis aimed at identifying regulatory mechanisms at the protein level, allowing rapid and specific regulation of transcription factors using GLS as a model. The general introduction and the first chapter provide background on protein level regulation and underline the importance of these mechanisms in regulating transcription factors. The remaining chapters report the identification of multiple new regulators of MYB transcription factors, potentially involved in their regulation at multiple steps of their activation. Plant signaling in connection with transcription factor regulation is an exciting field, allowing research on multiple regulatory mechanisms. This thesis shed light on the importance of integrating all steps of transcription factor activation in a regulatory network in deciphering the complexity of plant responses.
| Original language | English |
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| Publisher | Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen |
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| Number of pages | 247 |
| Publication status | Published - 2015 |