Better understanding plants’ complex environmental and food-producing roles is the focus of a new global research program being led by The University of Queensland.
The University of Queensland is spearheading an ambitious global research program to fundamentally change the approach to plant breeding to lift the performance of food crops and the sustainability of plants in nature.
The intention, under the recently created Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, is to provide a platform on which specialists in different aspects of plant genetics and physiology can combine their knowledge.
The centre’s director, Professor Christine Beveridge from The University of Queensland, explains that while a lot is known about the different genetic components of plants and their agronomy, it is specialised and disconnected. “We need to assemble this so that we know much more about how all the different parts of a plant work and fit together as a whole plant system.
“The knowledge exists,” she says, “but spread across different plants, crops, industries and environments. For example, an avocado looks very different to a cereal, but they have much the same genes controlling flowering time. It’s the same for many plants and why the whole plant kingdom is a tremendous genetic resource.”
The centre will bring together specialists from 13 academic and industry partner organisations from Australia, Europe, Asia, the US and Canada. The objective is to apply ‘groupthinking’ to plant breeding obstacles that are limiting yields and ecosystem sustainability.
Professor Beveridge says the objective is to increase the genetic rate of gain needed to keep crop yields in step with the rising world population – projected to rise by 25 per cent over the next 30 years – as well as to enhance sustainability of plant life generally.
Professor Beveridge illustrates the scale of the untapped genetic potential in plants by pointing to the fact that two-thirds of all the calories provided by plants for human consumption come from just three species – maize (corn), wheat and rice.
She says the difficult goal of doubling the genetic rate of gain for these food staples from one per cent a year to two per cent could become more achievable by tapping the genetics of other plants – both cultivated and wild.
“That’s why we have to bring together all we know across different plant science disciplines and to see plants as interconnected systems at the genetic, physiological and crop levels.
“Learning more about how all elements of a plant function and fit together then puts us in a much better position to more accurately predict what would happen, and what the benefits would be, if we modify any part of those systems.”
Professor Beveridge’s own investigations into what determines tillering in sorghum is an example. She explains how for all plants, branching and tillering is a fundamental system involving light energy, nutrients and hormones, and the genes that regulate these components.
Working with garden pea and Arabidopsis, Professor Beveridge’s team has identified the relevant genes in these plants and built a model that shows, diagrammatically, how tillering works.
They are now working to extrapolate this to sorghum, an important commercial crop. Tillering can have a big impact on crop yields but is strongly influenced by climate variability.
“We know very little at the genetic/mechanistic level about what drives tillering in sorghum,” Professor Beveridge says. “But by studying the system at work in pea and Arabidopsis we can see, first, if any genes correlate with what we know in sorghum.” If there are matches, she says, they can use their knowledge of peas to create a model to identify how genetic changes in sorghum might affect tillering.
“It is all about testing a model we already have for one plant species and seeing if we can use it to add value to another – in this case, improved prediction of gene behaviour in sorghum phenotypes,” Professor Beveridge says.
This could be important for sorghum growers because the number of tillers can affect yield positively or negatively, depending on conditions. Tillering occurring too early, for example, can lead to water and nutrients being used up before the tillers are productive.
“So if you want to breed a sorghum variety for a particular environment you need some genetic control over tillering,” she says.
“But because phenotypes are so responsive to environment the genetics are hard to study because the environmental variation is so huge. However, if you know that response to environmental variation is due to tillers and nitrogen use, and you know how sugars (the product of photosynthesis) and nitrogen (including fertilisers) affect gene regulation, then you can understand why some genetic differences are active in one environment and not another.
“You can see why this can get messy, but if you have a guiding model, albeit from another plant species, you can proceed with more certainty in breeding for particular environmental conditions. One of the objectives for sorghum is to breed a phenotype that is more robust and productive across a wide range of conditions – blunting the plant’s response to unfavourable conditions and enhancing its response to favourable conditions.”
Professor Beveridge says other crop traits that are not well understood at a genetic level include responses to biotic stresses such as high temperature and low moisture – something that native plants in natural systems have honed through their evolution.
“So it may be the models we can use for better understanding and applying improved climate resilience can come from native plants. Nature has come up with a countless solutions for biotic stresses. What can we learn about these systems, and how well we have applied these to our development of crops? After all, some of our breeding decisions were made several thousand years ago and we are still largely stuck with those decisions.”
It is this sort of capability that the Centre of Excellence has been charged with developing.
“It’s that layer of mechanistic understanding in between genes and phenotype. There’s always this interaction between genes, the environment and farm management that affects breeding and it’s the genes by environment interaction where everyone comes unstuck because we really don’t know what that is.”
The human challenge
The Australian Government announced funding for the centre at the end of 2019 and there is mounting anticipation as it was established this year. However, Professor Beveridge has a more immediate, human challenge.
The centre will be assembling specialists and postgraduate students from a range of scientific disciplines and backgrounds, and for whom ‘groupthink’ will be a challenge in itself.
“Research is competitive, and we have to find a way to make it inclusive,” says Professor Beveridge. “We have to agree on what advances need to be made, how we approach this, determine the data management and infrastructure needed to support a collaborative engagement, and even the language to use. Ecologists and geneticists, for example, have very different ways of explaining what they do.
“We are setting out to answer some very big questions, and to achieve this we have to be able to respect the research of people who use different yardsticks. For example, if I measure success based on whether I can demonstrate if a gene has a particular molecular function, am I going to give equal weight to the argument of an ecologist who believes a particular plant/environment relationship is the crucial factor? We all may need to learn more and judge less.
“It is going to be interesting – not only a scientific challenge, but also a paradigm shift in the way plant science is done.”
Republished with permission from The Queensland Alliance for Agriculture and Food Innovation (QAAFI) and The University of Queensland’s Faculty of Science.