Breeding new wheats with drought tolerant genes
Author: Michael Thomson | Date: 03 Jul 2014
The discovery of a gene that controls the way plants respond to drought could help lead researchers to the “holy grail” for many farmers: a new drought-tolerant, high-performing line of wheat.
Researchers at the ARC Centre of Plant Energy Biology, Australian National University, made the significant discovery several years ago of a protein that controls the amount of a signal between chloroplast and nucleus of a plant that regulates its response to drought.
They are now using that knowledge to screen wheat populations to find plants that lack copies of the crucial gene, which should mean they make more of the signal and survive longer and grow better in times of drought.
Leading the research at the ARC Centre of Plant Energy Biology is Professor Barry Pogson, who said the model plant used in the initial research survived 50 per cent longer than a normal plant when no water was added.
“During drought these plants continue to do photosynthesis and continue to grow whereas normal plants just stop growing and ultimately die,” Professor Pogson said.
“Nothing grows when there is no water at all but if the plants can survive better in a short to medium-term drought then farmers could get better, more reliable yield.”
Prof Pogson said initial work was done with a relative of canola, but preliminary research suggested the same protein was present in wheat, which meant the research could have significant repercussions for Australian farmers and global food supply.
“It could mean improved productivity in dry seasons and regions. For example, if there was a delay in spring rains, varieties with drought tolerance would still maintain biomass to ensure good grain filling when the rains arrive.”
Long-term collaborator at CSIRO, Dr Gonzalo Estavillo, said the gene regulating the plants’ drought response was called SAL1 and any plants lacking one or more functional copies of the gene should be more drought-tolerant.
Arun Yadav, who works with Prof. Pogson, discovered that wheat plants have up to seven copies of the gene, and each may have slightly different functions related to drought tolerance and the production of the signal in different parts of the plant, like roots, seeds or leaves.
The Grain Research and Development Corporation (GRDC) recently agreed to support four years of research, to find wheat lines that lack at least one of the SAL1 gene and have more of the signal. The goal is to find wheat lines that are more drought tolerant, but without affecting agronomic performance.
Both GRDC and CSIRO have developed non-GM wheat populations that lack different genes and Prof. Pogson’s group are using them for the search. This demonstrates the importance of different research organisations being able to work together and the need to maintain a critical mass of research capacity across the country.
He said making use of existing populations and avoiding genetically modified populations would streamline the process and allow the product to reach the market much sooner.
Prof Pogson said it was important that the wheat retained other traits that farmers required, such as high yield and disease resistance.
Arun Yadav said they had already found wheat varieties that lacked two of the seven genes and early indications of drought resistance abilities were promising.
“The key is to find the one that works in the right tissue at the right stage of development or during drought in particular, and then we might only need to find reduced activity in one gene,” he said.
“The work is being undertaken in a high-performing line of wheat although we don’t yet know if the wheat plants lacking the two SAL1 genes are as good as the existing lines for yield, which is the vital factor for growers.”
Prof. Pogson said the goal for farmers was to maximise yield in good years, maintain it in the moderate years, and minimise losses in the bad years.
“Yield stability refers to getting good yield in most years and Australia does worse than most other countries because of extremes of climate and poor soils,” Prof. Pogson said. “Projects like this one working towards getting more stable yield are better for profitability.”
Prof. Pogson said as Australia’s climate becomes more variable the need for wheat that could tolerate mid-season dry spells would continue to grow.
“The big pressure on agriculture is we have to increase food outputs by up to 70pc by 2050 to meet the growing needs of the world’s population.
“Australia is a major exporter of wheat, and wheat is second only to rice as a food source for the world’s population, so the sustainable production of wheat in a variable climate is critical.”
“From a research and development perspective it is very promising to go forward from model plants into crops. It is still too early to know if we will achieve the desired goal, but we are determined to try and succeed.”
Barry Pogson, Australian National University
02 6125 5629
Michael Thomson, Senior Consultant, Cox Inall Communications
07 4927 0805, 0408 819 666
GRDC Project Code ANU00011, ANU00020