Genetics of Meiosis in Cereals

The Genetics of Meiosis in Cereals research group is led by Dr Jason Able. We are located in the Waite Main Building (Lab GN15). The research is principally funded through the Molecular Plant Breeding CRC, Department of Education, Science & Training (DEST) and the GRDC. The group has a close affiliation with several members of the ACPFG including Professor Peter Langridge. Opportunities exist to undertake research within the group as students of the University of Adelaide or as visiting fellows from overseas institutions. Please contact Jason for information about these opportunities. The group is currently composed of young aspiring scientists at Post-Doctoral, PhD and Honours level.

Major Research Theme

Our research focus is centred on the biological process referred to as meiosis. Meiosis is essential for the majority of sexually reproducing organisms. During early meiosis there are three major events that occur; chromosome pairing, synapsis and recombination. Through the process of meiotic recombination, desirable combinations of alleles can be produced. These combinations ultimately lead to the genetic diversity that we see from generation to generation. In order to further our understanding of recombination (as well as chromosome pairing and synapsis) we use the polyploid bread wheat and the diploid barley. Bread wheat (along with rice) is one of the world’s most important cereals. With each cell containing the genetic content of three genomes, it also makes this cereal complex in its genetic make-up. During meiosis, although the chromosomes of the three genomes are all very similar to one another, only like chromosomes (otherwise known as homologous chromosomes) pair up with one another. The mechanisms that control this pairing (and subsequent recombination) in bread wheat are still poorly understood, although significant research published recently from our group (when viewed with what has been published in the past by Professor Graham Moore’s group – see below) has uncovered some interesting and novel results (see Boden et al. 2009). Through further understanding the events that occur during early meiosis, we will eventually be able to control and/or modify such a process. This will enable the generation of superior cereal varieties in breeding programs that are adaptable to a wide range of environmental conditions.

Research Highlights

Meiosis in wheat and rice: are the interactions and regulation of this process conserved between other diverse eukaryote organisms?

Meiosis is an ancient, evolutionarily conserved cellular process and a key driver for the generation of genetic diversity within sexually reproducing organisms. This DIISR funded project, awarded through the Australia-India Strategic Research Fund (AISRF) in collaboration with colleagues at the University of Delhi, seeks to determine the genes that regulate and interact with one another during meiosis in wheat, rice, and other diverse organisms. Specifically, this project is examining; to what extent is transcriptional regulation responsible for the orderly progression of meiosis in bread wheat (a polyploid) and rice (a diploid); and, what meiotic genes are highly conserved across diverse organisms? To answer these questions, yeast one-hybrid analysis, quantitative PCR, and bioinformatics approaches are being utilised. The potential outcomes of this work will enable plant breeding programs to develop new strategies for the introgression of genetic material from wild relatives which have desirable phenotypes, but, which at present, do not readily cross to produce fertile hybrids. See Khoo et al. (2008) and Bovill et al. (2009) for further information relating to this research.

Using microarray technology to investigate bread wheat during meiosis

Microarray technology is constantly evolving. Initially this technology was designed as a high throughput platform to quantify gene expression. While the microarray research component conducted within the Genetics of Meiosis in Cereals research group was published in 2006 (see Crismani et al. 2006), the experiments enabled the identification of some 350 meiotically-regulated transcripts where further research has now been directed. In conducting the array experiments we used the wheat Affymetrix GeneChip and screened across seven stages of anther development in bread wheat (pre-meiosis, leptotene to pachytene, diplotene to anaphase I, telophase I to telophase II, tetrads, immature pollen and mature anthers). Selection of candidates that are now being pursued was based on those candidates having moderate to high expression during the early stages of meiosis (e.g. pre-meiosis, leptotene to pachytene) when compared to the other stages, as well as being novel (with respect to the sequence that was available when screened across other sequences in publicly available databases).

Investigating the bread wheat proteome during meiosis

This project is investigating a proteomics-based approach to study the similarities and differences that exist between anther protein profiles of different wheat varieties (with varying ploidy levels) and the screening of mutants that have known meiotic phenotypes. These two objectives will enable us to: 1) gain a greater appreciation as to how polyploidy has contributed to plant evolution in the genus Triticum; and 2) by comparing wheat mutants with wild-type wheat plants, determine proteins that are involved in bread wheat meiosis. To conduct the 2-dimensional gel electrophoresis (2-DE), we have isolated meiocyte-enriched protein extracts and optimised the conditions needed to generate reproducible proteome profiles. To date, multiple proteins have been identified that are differentially regulated between the wild-type wheat and mutant lines during meiosis and are now the focus of further analysis. While particular attention is being given to studying those proteins that have known roles during early meiosis, given the complexity of the polyploid bread wheat genome, novel proteins discovered are also being pursued.

Key Papers

• Boden SA et al. (2009) The Plant Journal 57 (3): 487-497
• Bovill et al. (2009) Functional & Integrative Genomics 9: 219–229 DOI: http://dx.doi.org/10.1007/s10142-008-0097-4
• Khoo KHP et al. (2008) Functional Plant Biology 35 (12): 1267-1277
• Lloyd AH et al. (2007) BMC Plant Biology DOI:10.1186/1471-2229-7-67
• Boden SA et al. (2007) BMC Molecular Biology DOI:10.1186/1471-2199-8-65
• Able JA et al. (2007) Trends Plant Sci. 12 (2): 71-79
• Crismani W et al. (2006) BMC Genomics DOI: 10.1186/1471-2164-7-267
• Able JA & Langridge P (2006) ‘Wild sex in the grasses’, Trends Plant Sci. 11 (6): 261-263

Collaborative Linkages

• National:

  • Professor German Spangenberg, DPI Victoria.
  • Professor Peter Langridge ACPFG, University of Adelaide, South Australia.
  • Dr Amanda Able, Plant Protection, School of Ag, Food & Wine, University of Adelaide.

• International:

• Professor Graham Moore, John Innes Centre, Norwich, England.
• Dr Sanjay Kapoor, University of Delhi South Campus, Delhi, India.