Applying the lessons from Nature: Oxidative stress tolerance in wild ancestors of wheat

A project undertaken at the School of Biological Sciences, Flinders University, and supervised by Kathleen Soole

Oxidative stress is a consequence of living in an oxygen-rich atmosphere and one of the many challenges that plant’s face during growth and development.  It can be exacerbated by environmental stresses such as high temperatures, drought and salinity. Oxidative stress occurs when highly reactive oxygen radicals (Reactive oxygen species, ROS) accumulate in a cell and cause damage to DNA, protein and lipids with dramatic effects that often lead to cell death.

Processes for detoxifying ROS and minimising their production exits in all cells and the presence of these have been linked to better growth in plants in laboratory studies. Global climate change and increasing populations will put pressure on our current agricultural productivity; it has been predicted that we will need a 70% increase in productivity to meet our needs by 2050. This will require us to increase out yields in poorer growing areas and we will need crops that can cope with increased oxidative stress.

While cultivated crops have been bred for better yields, their gene-pools  have become very limited due to the long history of human selection. In contrast, wild species and the progenitors of our current crops have diverse genotypes and can often be found in harsher environments. Their still diverse gene pools suggest that they may have retained genes linked to better oxidative stress tolerance. The aim of this project is to study physiology, biochemistry and genetics of a mitochondrial pathway strongly linked to oxidative stress tolerance, the alternative pathway of respiration in the wild ancestors of bread wheat to gain a better understanding of this pathway and for further application in wheat breeding.

The significance of the project is based on the fact that there is a much wider natural polymorphism of genes encoding tolerance to oxidative stress in wild species and that this  knowledge,  can be used in the conventional breeding of wheat, to generate more stress tolerant germplasm.

The main objective of this project is to assess the level of oxidative stress tolerance exhibited by wild species of wheat such as species from the genera, Triticum and Aegilops, which are the ancient relatives of cultivated wheat and have been growing under the process of natural selection for millions of years. They are diverse and show tolerance to a range of multiple environmental stresses. However, nothing is known about Aox in these plants and how the AP may contribute to tolerance to oxidative stress.  This project proposes to close this gap studying wild Triticum species by screening and selecting of the most tolerant accessions to multiple oxidative stresses and assessing the contribution of the AP to stress tolerance.

Figure 1.