Boosting wheat yields in the face of climate change
Rising temperatures due to climate change are reducing crop yields, which compromises food security. EU-funded researchers are working to make wheat less susceptible to heat so that it remains a safe and reliable food source.
© Bayer, 2016
The global population is 7.5 billion and rising and wheat is one of humanitys main food sources. Photosynthesis is the process by which wheat and indeed all plants change light, water and carbon dioxide into the energy that fuels their growth and productivity. Enzymes increase the rate of such processes, and one enzyme that is vital for driving photosynthesis in wheat is Rubisco. To make Rubisco work, another enzyme, called Rubisco activase (RCA), is also needed.
Higher temperatures are liable to reduce the effectiveness of RCA, making photosynthesis less efficient and lowering wheat productivity. Studies show a 3-5 % drop in wheat yields for every 1 °C increase in average temperature above 15 °C a loss of around 190 kg per hectare. Temperature can have a more severe effect on yields than water availability.
The EU-funded Heat-Wheat project is exploring ways of increasing the stability of RCA in warmer temperatures. Researchers are looking for variants of the enzyme that stand up well to heat, either due to naturally occurring traits that have evolved in hot climates or changes to their DNA sequence made in the laboratory.
Improving heat tolerance of photosynthesis in wheat will prevent or diminish yield losses under future climate scenarios. This advance will make it possible to grow wheat in hotter places, helping to ensure a more secure food supply.
As project coordinator Alexander Gallé from the Bayer Crop Science Division in Belgium explains: We aim to understand what makes RCA more thermostable so that photosynthesis and crop productivity can be maintained even in hotter conditions. The key to success is the optimisation of a robust RCA investigative procedure with a sufficiently high throughput that allows us to screen collections of plants and test RCA variants under elevated temperatures.
Wheats wild relatives
Heat-Wheat uses a combination of software tools for understanding biological data and rapid laboratory analysis procedures to screen wild grasses related to wheat and examine differences in their DNA sequences. The analysis is supported by in-house genetic information on wheat relatives. It also takes account of findings related to RCA in wild rice species from the Australian savannah which have been shown to have high heat tolerance.
In addition, state-of-the-art techniques are used to create further wheat RCA variants with a view to identifying those that remain productive in higher temperatures. All of the variants are then tested for heat tolerance.
New types of wheat
Heat-Wheats research feeds into Bayers crop innovations and has the potential to stimulate further academic and industrial research. It will help with the breeding of new wheat varieties and increase knowledge of RCA and its role in photosynthesis, particularly in wheat. Genetic optimisation and breeding programmes will be used to develop seeds containing heat-tolerant variants of wheat RCA that emerge from Heat-Wheat.
Exploring the natural diversity of heat stable RCA in wild relatives of wheat helps us to develop more heat-tolerant wheat varieties. Moreover, we evaluate all available genomic data to help determine the molecular basis of heat-stability in RCA using computer-based modelling, says Gallé.