How plant DNA will help shape the future of native seed production areas

Dr Katarina Stuart (left) with a fellow postdoc, collecting plant DNA samples at the Jarrega SPA in WA for genetic analysis.

This guest blog is contributed by Dr Katarina Stuart, a Research Fellow at Macquarie University.

The age of genetics is transforming how people explore their personal history — through their DNA. With a drop of saliva or a strand of hair, you can uncover family connections, trace your ancestry, and learn about traits you might pass to your children. But did you know we can — and routinely do — the same kind of genetic profiling on plants?

An ongoing collaborative project between Greening Australia and Macquarie University, funded by The Ian Potter Foundation, is applying these techniques to analyse the patterns locked away in native plant DNA.

The results will help seed production practitioners make better informed decisions about how to design and manage native seed production areas (SPAs) to maximise seed health and the evolutionary potential of plant species.

How can tracking a plant’s genetics inform seed sourcing in SPAs?

Just like people, each individual plant has a family, and an ancestral lineage that can be traced back in time. When you go on a bushwalk and see one towering gum tree, that individual tree will have siblings, parents, cousins and many more distant relatives. The term ‘population’ is used by scientists to describe a distinct group of plants that contains some of these extended families, where their shared history may result in genetic clusters.

This shared history, combined with differences in environment, may mean that populations can be quite different from one another and potentially adapted (genetically matched) to the local environment. For example, Australian Groundsel (Senecio lautus) populations that inhabit windy rocky headlands are shorter than dune populations, even when grown in a different environment – indicating that this is a genetically-based adaptation. Scientists can analyse plant DNA to uncover the genetic basis for these differences.

Analysis of plant DNA to identify adapted genes is a growing field in Australia and internationally. Studying dune vs headland populations of Senecio lautus is one current example. Photo credit Conrad Gilbey CC BY-ND 2.0.

A key consideration when sourcing seeds or seedlings to set up a SPA is to make sure that you have strong representations from lots of different populations of a species. This will ensure that a SPA is helping to capture genetic signatures from many different source populations, and this genetic mixing can also produce seed that has high genetic diversity.

Why is high genetic diversity important for SPAs?

Genetic diversity is the degree to which an individual’s DNA contains a healthy mix of different genetic lineages. A lack of genetic diversity results from inbreeding, which can increase the chances of harmful traits being expressed. We see this in some purebred dogs, which have been bred from close relatives and may carry genetic disorders.

Some populations of native plant species are large and contain a lot of genetic diversity, but in smaller remnant patches of bushland, individuals in populations may be more related and have less potential to crossbreed – which can result in inbred or less genetically healthy individuals.

Plant populations in isolated remnants of bushland can have reduced opportunity to crossbreed, which may result in inbreeding and a loss of genetic diversity. That’s one reason it’s important to connect up remnants with strategic restoration plantings.

Why is it particularly important to maximise the genetic mixing of plants and produce seed with high genetic diversity in a SPA? Seed for environmental restoration needs to be genetically diverse to increase the likelihood that we establish healthy, self-sustaining populations. Seed produced by genetic mixing can result in fitter plants – for example better germination and plant survival – which can translate to improved on-ground results for restoration and conservation.

How can we use plant DNA analysis to produce seed for the future?

Just like in humans, a plant’s DNA forms the genetic blueprint that underlies all their traits: how fast they grow, how resistant they are to diseases, or how well they tolerate extremes such as droughts. Having a diverse mix of genetic signatures in their DNA gives plants high evolutionary potential — the ability to adapt to changing environmental conditions and succeed across various landscapes over time.

As well as sourcing from multiple distinct populations of a plant species when establishing a SPA, we can deliberately select populations that may carry genetic signatures or traits of value for helping plants thrive into the future. For example, a plant population from a hot and dry region may have adaptations that are crucial for resilience in a future shaped by ongoing climate change. This can potentially build climate resilience into seed produced from the SPA.

Greening Australia’s Dr Melinda Pickup and Bayden Smith with Melaleuca hamata seedlings from different provenances, to be planted at the Jarrega SPA in WA. Photo credit Jesse Collins.

As well as carefully selecting the initial genetic pool for a plant species in the SPA, we should also closely monitor the seed produced to detect any significant loss of genetic diversity ongoing, which could indicate inbreeding.

Applying genetic analysis can help maximise the long-term success of seed — not just for one generation, but for many to come, ensuring its effectiveness in conservation and restoration efforts.

What research is being done in the collaborative project between Macquarie University and Greening Australia?

At Macquarie University, we are conducting several experiments to understand how management practices influence the genetic health of plants grown in SPAs. This includes experiments to assess the genetic health of seed produced from mixing multiple source populations and comparing it to the genetic health of seed collected from wild source sites. We are also investigating how different life history traits — such as whether a plant is pollinated by birds, insects, or wind — can affect the ease or difficulty of producing genetically healthy seed in a SPA. Stay tuned to hear about the results!

Samples from different provenances of several species, including Calothamnus quadrifidus in this photo, have been collected at Jarrega SPA for genetic analysis. The results will be shared as the genetic analysis progresses.

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