About the Project
Pollen development is vital for crop productivity and is important for future food security. Despite this, there is limited knowledge of the molecular mechanisms involved in pollen development and the impacts of abiotic stress. This is important given the sensitivity of pollen to periods of temperature and drought stress, which are expected to increase in the face of environmental change (Rieu et al, 2017).
In our previous research on the genetic model Arabidopsis thaliana, we have identified key regulators of sperm development and fertility including the transcription factor DUO1, which is widely conserved in major food crops such as maize, wheat, rice, and tomato (Brownfield et al. 2009). Our work has established a regulatory framework for male germline development (Berger and Twell, 2011), which includes the discovery of a novel class of zinc finger transcription factor, which forms an important regulatory node downstream of DUO1 (Borg et al., 2011, 2014).
Project Aims: The aims are to uncover the organisation and function of key gene networks in pollen development and to examine how these respond to environmental stresses. The project will involve genetic and molecular studies of both model and crop species and will combine co-expression and co-function network analyses to understand male fertility. The research will increase understanding of pollen regulatory networks and will help to identify pathways through which the effects of environmental stress on reproduction may be mitigated.
The major objectives of the proposed work packages are, first, to characterise mutants, in model and crop species (eg. Arabidopsis, tomato), which disturb DUO1 network function, and second, to explore how environmental stresses (temperature and drought) impact germline networks and pollen fertility.
1. Germline functions will be examined by characterising existing mutants with defects in network components. This will involve genetic and phenotypic analysis including studies of cell fate, pollen viability and seed development. Whole genome sequencing may be used to identify selected mutant loci for further molecular analysis.
2. Transcriptome data from wild type and knockout mutants will be used to inform an emergent regulatory model as a means to explore network organisation and response to environmental stress. Computational predictions of co-expression and co-function networks, and the responses of these to environmental stress, will enable the discovery of novel components relevant to gamete fertility and stress tolerance.
Main techniques to be used in 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.
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.
Berger, F. and Twell, D. (2011) Germline specification and function in plants. Annu Rev Plant Biol 62:461-84.
Rieu, I, Twell, D., Firon, N. (2017) Pollen development at high temperature: from acclimation to collapse. Plant Physiology 173:1967-76.