Manuka honey is worth hundreds of millions of dollars in export value. Scientists are closing in on what creates its active ingredient. Photo / File
Manuka honey is worth hundreds of millions of dollars in export value. Scientists are closing in on what creates its active ingredient. Photo / File
Our understanding of gut health has ballooned as we've learned more about the communities of beneficial bugs that live within each of us.
We now know this microbiome contributes to everything from immunity and obesity to mental health.
Now scientists suspect microbes might also be what gives one of New Zealand's most lucrative exports, manuka honey, its active ingredient.
The native manuka plant acts as the substrate for the unique and valuable honey, which contains high levels of a compound called methylglyoxal.
This is better known to consumers around the world by the different systems that producers use to grade manuka honey – MGO or unique manuka factor, or UMF.
Methylglyoxal is formed from nectar rich in a substance called dihydroxyacetone, or DHA.
"We do not yet understand why some flowers on some manuka plants produce high levels of DHA and wonder if the micro-organisms in the flowers might contribute to this," said Dr Hayley Ridgway, a senior scientist at Plant & Food Research.
"Our previous work has shown that manuka is a plant for which microbes significantly impact growth and chemistry. We also know that DHA can be made by micro-organisms."
In a just-launched study, Ridgway and fellow researchers from Manaaki Whenua – Landcare Research and Lincoln University aimed to find out if their theory was correct.
Working in partnership with Ngai Tahu Farming Ltd and Ngati Porou Miere, the team planned to collect flowers from manuka lines known to produce high and low amounts of DHA in the nectar.
"We will make a collection of microbes from flowers and study whether they are able to make DHA by themselves."
They'd then add selected microbes back to those low-DHA manuka lines to see if they could actually increase DHA production.
"In this way we will increase the value of the nectar on the plant and the honey derived from it."
The native manuka plant acts as the substrate for the unique and valuable honey, which contains high levels of a compound called methylglyoxal. Photo / File
The work would draw on state-of-the-art DNA tools to reveal just how microbes were doing the job.
"Manuka is a plant rich in microbes that can influence many aspects of its growth and health," she said.
"Sorting through this diverse group of different organisms to find those responsible for augmenting DHA, if present, will be a challenge - and there is every possibility that it is a step-wise process contributed to by more than one microbe, increasing the potential complexity."
But if they could solve the puzzle, they stood to unlock some of the secrets of the intriguing relationship between the native plant and the microbes it hosted.
The next step would be to seed New Zealand's plantation with a new catalyst, or create high-value seedlings.
"Our focus is on high value honey but we may also find other interconnections and dependencies with other microbes along the way – analogous to the frontiers in human health," she said.
"We are at the forefront of an exciting new science area that will demonstrate the currently hidden world by which microbes support our wonderful native plants.
"We hope we will generate spill-over benefits to functional studies on microbes in other valued native flora."
Ridgway said sampling would be carried out with the support of Maori partners, and the microbes would be carefully labelled so ownership could be traced back to the rohe, and hence mana whenua, to which they belonged.
The study is being supported with a million-dollar grant from the Ministry of Business, Innovation and Employment's Endeavour Fund.
