New research into the impacts of fungi growing inside Banksia seeds could lead to better ways of restoring this iconic Australian native plant back into nature.
Allison Mertin, from the Research Centre for Ecosystem Resilience at the Australian Institute of Botanical Science, said her pioneering study, published in Fungal Biology, revealed fresh insights into how Banksia seeds functioned.
Allison said seeds contain not only the embryo and nutrients required for growth, they may also contain microbes, such as fungi and bacteria that can exist as endophytes living within their host plant.
“Most of the research in this seed fungal endophyte area comes from agriculture, in plants such as wheat, corn, and barley. The endophytes within these seeds can be beneficial because they can increase plant growth – so research has commercial benefits,” Allison said.
“However, there is very little research into how fungal endophytes work in natural systems and this is the first study in Australia that looked at what was growing inside the Banksia seeds.”
The research took Allison to the Royal National Park in Sydney, the NSW Central Coast and the Blue Mountains Region where she focused on two species of Banksia - B. serrata and B. ericifolia that grew close together.
“We discovered, for the first time, that these unique fungi, which had been seen growing on the outside of Banksia cones, was actually growing inside the seed,” Allison said.
“And even though the plants were growing only metres away from one another, they had fungi that were very different. They had very different functions and contributions to the ecosystems they grew in. That’s something we didn’t expect.”
Based on results from isolation and culturing, as well as DNA sequence analysis, Allison found that the Banksia seed housed a diverse range of fungal endophyte species.
“We removed the fungal endophytes from the seed and identified which species they are,” Allison said.
“The better we understand how the seeds function, the more success we will have in restoring Banksias into Australia’s natural ecosystems.”
One of the puzzles associated with fungal endophytes in Banksia seeds is how they get there, however Allison said there could be a few different ways.
“They could come up though the soil and up through the roots and transfer into the plant tissue and into the seeds.” Allison said.
“Then there have been studies into agricultural seeds where fungal endophytes are transferred onto the next generation. This is called vertical transmission. We assume there must be benefit for this to happen.
“And there is also horizontal transmission, where they can come in through pollinators, through the flower as well. Fungi is present in the air we are in right now and it can get into the seed that way, too.
“For the Banksias, the fungi weren’t in every seed so we think it might be coming in through particular pollinators.”
Allison said one of the Australian Institute of Botanical Science’s goals was to conserve biodiversity in its National Seed Bank that will help restore and safeguard biodiversity nationwide.
“We are not just collecting plant seeds but indirectly also collecting the diversity in the seed microbial community and we are just starting to get a better understanding of this hidden yet very important world,” Allison said.
“Understanding what type of fungi there is in these seeds is the precursor to understanding what they are doing and why they are there.
“This information is very useful for restoration projects. If we are going to use Banksia seed to regrow vegetation at a site, one thing we might do is check that the seed we are planting has that species of fungi inside it, as these fungi may have a role in recycling nutrients in the ecosystem and play a role in plant health.”