Histone demethylation as a regulator of root system architecture

Armstrong, Emily May (2018) Histone demethylation as a regulator of root system architecture. MSc(R) thesis, University of Glasgow.

Abstract

Root system development must be perceptive, responsive, and highly plastic to ensure survival of a plant under a barrage of biotic and abiotic stressors. Thus, plants must have means to modify a strict developmental programme to adjust root system architecture to the environment. Post-translational modifications of histone tails are part of a regulatory machinery that controls gene expression, with each specific modification correlating with either activated or repressed transcription of target genes. Here, a histone demethylase enzyme, removing transcriptionally repressive tri-methylation from lysine 27 on histone 3 (H3K27me3), was investigated for its potential role in regulating root system architecture. When subjected to light or nitrate deficiency Arabidopsis thaliana mutant plants defective in H3K27me3 demethylation failed to phenocopy increased lateral number and length observed in wild type. The mutant plants also showed a reduction in lateral root emergence and elongation in standard growth conditions, suggesting that H3K27me3 demethylation is causally upstream of the stress signal input into the developmental programme. In a candidate-gene approach, transcript levels were measured in root tissue for several auxin-transport and auxin-signalling genes that showed higher H3K27me3 levels in the mutant. The expression profiles varied over a time course of 2 weeks, with a general activation occurring on day eight, typically coinciding with first lateral root emergence. Only one of the selected genes showed lower transcript levels in the mutant than in the wild type, and could therefore be a direct target of H3K27me3 demethylation.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: Root, histone, epigenetic, development, auxin, nitrogen, demethylation.
• Subjects: Q Science > QH Natural history > QH301 Biology; Q Science > QH Natural history > QH426 Genetics; Q Science > QK Botany
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences > Molecular Biosciences
• Supervisor's Name: Amtmann, Professor Anna
• Date of Award: 2018
• Embargo Date: 27 March 2022
• Depositing User: Doctor Emily May ARMSTRONG
• Unique ID: glathesis:2018-8775
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 27 Mar 2018 13:49
• Last Modified: 29 Mar 2021 07:56
• URI: https://theses.gla.ac.uk/id/eprint/8775