The Role of Tapetal Nurse Cells in Supporting Male Germline Functions

Aldridge, Billy (2018) The Role of Tapetal Nurse Cells in Supporting Male Germline Functions. Doctoral thesis, University of East Anglia.

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The development of germlines is an important timepoint in the lifecycles of multicellular organisms. In plants a somatic cell layer, called the tapetum, supports the development of the male germline. The tapetum controls many aspects of germline development, and as such has been an important target for research on male fertility. While large effect genes have been identified in screens for male sterility, tapetal research is hampered by the difficulty in isolating high-purity tapetum and the lack of whole genome sequencing data. In this thesis, tapetum function was explored by the application of fluorescence activated cell sorting to Arabidopsis thaliana plants expressing a tapetal GFP reporter.

RNA-sequencing of isolated tapetal cells has led to the discovery of novel tapetumenriched and tapetum-specific genes. Mutant plants of these genes show defects in both tapetum and pollen development. Sequencing of single tapetal cells has allowed the inference of gene expression through developmental time. Tapetum gene expression could be classified into two broad patterns, early and late, with a developmental switch inferred at anther stage 8. Analysis of temporal gene expression has revealed new gene expression profiles of known tapetal genes as well as novel candidate genes expressed at specific developmental stages. Whole genome DNA methylation analysis of the tapetum has revealed sites of tapetum-specific hypermethylation controlled by both canonical and non-canonical RNA-directed DNA methylation pathways. The observed methylation patterns in the tapetum and sexual lineage has led to a model of small RNA transfer from the tapetum.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Nicola Veasy
Date Deposited: 14 Mar 2019 14:32
Last Modified: 31 Mar 2021 00:38

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