Understanding meiosis and the implications for crop improvement

Abstract

Abstract. Over the past 50 years, the understanding of meiosis has aged like a fine bottle of wine: the complexity is developing but the wine itself is still young. While emphasis in the plant kingdom has been placed on the model diploids Arabidopsis (Arabidopsis thaliana L.) and rice (Orzya sativa L.), our research has mainly focussed on the polyploid, bread wheat (Triticum aestivum L.). Bread wheat is an important food source for nearly two-thirds of the world's population. While creating new varieties can be achieved using existing or advanced breeding lines, we would also like to introduce beneficial traits from wild related species. However, expanding the use of non-adapted and wild germplasm in cereal breeding programs will depend on the ability to manipulate the cellular process of meiosis. Three important and tightly-regulated events that occur during early meiosis are chromosome pairing, synapsis and recombination. Which key genes control these events in meiosis (and how they do so) remains to be completely answered, particularly in crops such as wheat. Although the majority of published findings are from model organisms including yeast (Saccharomyces cerevisiae) and the nematode Caenorhabditis elegans, information from the plant kingdom has continued to grow in the past decade at a steady rate. It is with this new knowledge that we ask how meiosis will contribute to the future of cereal breeding. Indeed, how has it already shaped cereal breeding as we know it today?

The evolution of the land plant life cycle

“…For this reason, we conclude that future enquiries into the developmental mechanism(s) by which the embryophyte life cycle evolved would profit from detailed diagnoses of the molecular ‘drivers’ of the plant cell cycle, the induction of meiotic versus mitotic cell division, and a host of other fundamental phenomena. Scrutiny of meiotic gene candidates and factors that contribute to homologous chromosome pairing will be a particularly important and fertile field of inquiry (see Able et al. , 2009).…”

A novel partial male sterility resource in bread wheat

“…However it could be of interest in i) situations of recurrent selection or of dynamic management where limited intermating is required and ii) in studies of genes involved in microsporogenis and pollen development. In recent years, using findings from model organisms, research has been undertaken to understand the mechanisms that govern the cellular process of meiosis and microsporogenesis in hexaploid wheat (Able et al 2009). ms-Moulin should be useful in that context.…”

Comparison of homoeologous chromosome pairing between hybrids of wheat genotypes Chinese Springph1band Kaixian-luohanmai with rye

“…Allopolyploids behave as cytological diploids during meiosis with only homologous chromosome pairing (Jenczewski and Alix 2004;Able et al 2009). This ensures genome stability and fertility (Sánchez-Moran et al 2001).…”