NZ school children discover the power of mānuka in quest for weed killer

 

Schools and pupils from all over New Zealand are working with the University of Otago and Plant & Food Research to discover what secrets are locked within the wide variety of mānuka around the country.

They are exploring whether their local mānuka plants contain enough of a chemical  called grandiflorone to kill weeds, and whether the grandiflorone levels differ in mānuka growing in different parts of New Zealand.

This could result in the native plant’s leaf chemistry providing a natural weed killer.

The nectar from mānuka produces high-value mānuka honey, the basis of a boom in bee keeping around natural mānuka stands and extensive new plantings.

The leaf chemistry could provide an additional valuable product and may be important for the growth of this native plant.

Scientists Elaine Burgess, from Plant & Food Research, and Dr Dave Warren, from the Department of Chemistry at the University of Otago, are leading the project which has been supported by the Government’s “Unlocking Curious Minds” fund.

“Pupils collect foliage from their local mānuka, they then prepare a sample voucher, and extracts are made to test for herbicidal (weed killer) activity in a lettuce seedling assay,” Elaine says.

“They then send us sample extracts to analyse in our Plant & Food Research labs in Dunedin.”

Results are being uploaded to the database NatureWatchNZ to enable schools to compare the variations within mānuka in their own region, plus the differences around wider New Zealand.

 The project is already providing new scientific knowledge.

“Students at Musselburgh School in Dunedin have helped us discover quite big chemical differences in varieties of mānuka in the local area, so it’s a surprise to learn mānuka from a particular region will not necessarily have the same levels of grandiflorone,” explains Dr Warren.

A crucial aspect of the research is testing whether extracts from various mānuka plants stop lettuce seeds from growing.  Initial results show New Zealand mānuka are generally less potent than a related Australian species.

The focus now is to spread the hands-on testing kits around New Zealand to see if there is a mānuka variation here equal to, if not better than, the Australian plant.

“We’ve been very excited by the research so far, and look forward to the kits being circulated to places like the East Cape where we know there are significant amounts of mānuka,” Elaine Burgess says.

So far around 30 schools have been sent the kits, which include all the equipment and instructions necessary for the students to conduct the scientific investigations themselves.

Testing is spread over approximately two weeks, including collecting local mānuka, drying and pressing botanical voucher specimens, and extracting and testing on lettuce seeds.

“This is citizen science in action. We want students to not only gain new skills from conducting the experiments themselves, but also to learn about the nature of science, of testing, of researching and of coming to robust scientific conclusions,” Dr Warren says.

Results from the first wave of testing are being collated at Plant & Food Research in Dunedin while the next bundle of kits are being distributed to more schools around New Zealand.

The project is expected to continue for several years, dependent on further funding for this community science initiative.

Source: University of Otago

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Cracking manuka’s genetic code may mitigate the effects of myrtle rust

A nationwide science project that sequenced the manuka genome and is now exploring its genetic diversity may be instrumental in protecting the indigenous plant from the fungal disease myrtle rust.

Using state-of-the-art genome sequencing technologies, Plant & Food Research scientists mapped manuka’s genetic blueprint in 2015 and shared the information with tangata whenua and the New Zealand research community.

The research focus has since moved to using bioinformatic techniques to acquire a detailed understanding of the unique attributes of manuka’s genetic stocks – the data have been gleaned from around 1000 samples of manuka leaf collected nationwide in a collaboration with Landcare Research, the University of Waikato and key Maori partners.

The information generated is providing important scientific insights concerning the distribution and genetic diversity within and between manuka populations in New Zealand.

“A key objective of the project has always been to understand how genetic material is exchanged between manuka populations by pollen and seed dispersal to help whānau and hapū, and the honey industry, to develop unique stories around provenance, and help ensure genetic variation for conservation purposes,” says Plant & Food Research Science Group Leader Dr David Chagné.

“With the arrival of myrtle rust on the New Zealand mainland, we soon realised the need for an additional and more specific conservation application for the project.

“While it’s not clear just what effect myrtle rust will have on mānuka under New Zealand conditions, we should expect differences in susceptibility and resistance across the mānuka populations.

“By using the latest technologies for DNA sequencing and new methodologies for bioinformatic data analysis we can determine which parts of the genome are associated with tolerance.

“This will help us to better predict the potential damage from myrtle rust and determine how fast the various mānuka populations will respond to the disease.

“The data will assist with guiding research priorities for maintaining and protecting diversity in mānuka,” says Dr Chagné.

Research results from the project are expected to be released between June and August this year.

The Maori organisations assisting with stakeholder engagement and commercial support in the project are Ngati Porou Miere, Tuhoe Tuawhenua Trust, Atihau-Whanganui, Taitokerau Miere and Tai Tokerau Honey. The project is funded by the Ministry of Business, Innovation and Employment.