Principal Supervisor: Professor David Twell, Department of Genetics and Genome Biology
Co-supervisor: Dr Richard Badge
PhD project title: Making the male: the impact of germline gene networks on plant and crop fertility.
University of Registration: University of Leicester
Plant fertility, seed production and food security depend upon the vital role of haploid germlines which differentiate to produce male (sperm) and female (egg) gametes. Despite the importance of this process we have limited knowledge of the mechanisms involved in gamete development. This research aims to uncover fundamental mechanisms that underlie key decisions in plant gamete development and the role of germline gene networks in plant and crop fertility.
Through screens in the genetic model Arabidopsis thaliana, we have identified key regulators of male gamete development including the transcription factor DUO1, which is widely conserved in important food crops such as maize, wheat, rice, and tomato (Kim et al. 2008; Brownfield et al. 2009). Our work has established a regulatory framework for male germline development (Berger and Twell, 2011), and in recent BBSRC-funded work we have discovered DAZ1, a novel class of zinc finger transcription factor, which forms an important node downstream of DUO1 (Borg et al., 2014).
Project Aims & Description
This project will explore the functional conservation and mechanisms by which the DUO1-DAZ1 regulatory module coordinates cell division and sperm differentiation. Studies of gene function will include genes from Arabidopsis and from several crop species including cereals and tomato. Genetic and molecular analysis will be combined with comparative transcriptome analysis to uncover co-expression and co-function networks and their impact on sperm cell differentiation and plant fertility. The project seeks to; establish the conservation of DUO1-DAZ1 function in crop plants; to identify DAZ1 target genes and, to model how the target genes are integrated with the wider germline gene networks.
The research is expected to deliver novel information and tools of potential value in plant biotechnology and breeding applications such as hybrid seed production and the control of gene flow in transgenic crops.
Year 1. Construct novel duo1 and daz1/daz2 gene mutants from crops such as tomato and identify germline targets of the DUO1-DAZ1 regulon based on bioinformatic analysis of existing transcriptome data.
Year 2. Complete genetic and phenotypic analysis of duo1 and daz1 gene mutants and establish in vitro/in vivo DNA binding assays for DAZ1.
Year 3. Devise and evaluate a network model for the contribution of DAZ1-targets to male germline development and analyse their functions using gene-editing and by manipulating protein function.
- Borg, M., Brownfield, L., Khatab, H., Sidorova, A., Lingaya, M. and Twell, D. (2011) The R2R3 MYB transcription factor DUO1 activates a male germline-specific regulon essential for sperm cell differentiation in Arabidopsis. Plant Cell 23:1-16.
- Borg, M., Rutley, N., Kagale, S. Hamamura, Y., Gherghinoiu, M., Kumar, S., Sari, U., Esparza-Franco, MA., Sakamoto, W., Rozwadowski, K., Higashiyama, T. and Twell, D. (2014). An EAR-dependent regulatory module promotes male germ cell division and sperm fertility in Arabidopsis. Plant Cell 26:1-17.
- Brownfield, L., Hafidh, S., Borg, M., Sidorova, A., Mori, T. and Twell, D. (2009) A plant germ cell-specific integrator of cell cycle progression and sperm specification PLoS Genet. 5: e1000430.
- Kim, H.J., Oh, S-A., Brownfield, L., Ryu, H., Hwang, I., Twell, D*. and Nam, H-G*. (2008) Control of plant male germline proliferation by SCFFBL17 degradation of cell cycle inhibitors. Nature 455, 1134-1137.
- Berger, F. and Twell, D. (2011) Germline specification and function in plants. Annu Rev Plant Biol 62:461-484.
BBSRC Strategic Research Priority: Food Security
Techniques that will be undertaken during the project:
- Comparative transcriptomics (microarray & RNA-seq data); co-expression and co-function network analysis Integration of ‘omics’ data and network modelling
- Fluorescence and confocal laser scanning microscopy
- Manipulation of gene expression and protein function by transgenic analysis and gene-editing
Contact: Professor David Twell, University of Leicester