CRIs are collecting seeds in the race against myrtle rust

Pōhutukawa, mānuka, kānuka and other New Zealand seeds are being collected, grown, and tested for resilience to myrtle rust, a disease with the potential to wipe out entire native species and drastically change the country’s native landscape.

Myrtle rust attacks and can seriously affect plants in the Myrtaceae (myrtle) family, including pōhutukawa, mānuka, kānuka and rātā.

The fungal pathogen that causes myrtle rust is called Austropuccinia psidii. This fungus produces millions of small yellow-coloured spores that are easily wind-blown to new plants.

The pathogen was first found in Australia in 2010 and seven years later was identified in New Zealand. Since then it has spread quickly and has been reported on at least 600 properties.

An article by Suzette Howe, posted on the Manaaki Whenua – Landcare Research website, says the Ministry for Primary Industries (MPI) has launched a full-scale attack to better understand the disease and limit its impact on NZ’s  Myrtaceae plants.

Manaaki Whenua – Landcare Research is one of a team of institutes taking part in the research programme.  It will be working on the project closely with Plant & Food Research over the next two years.

“What we are trying to do is work out which species are going to be affected by myrtle rust, so to do that we are collecting seed from a whole range of Myrtaceae species, i.e. from the family that is going to be affected by myrtle rust,” says ,” says Manaaki Whenua – Landcare Research scientist Dr Gary Houliston.

“They’ll be sent to Australia to a screening facility, where they will be challenged with myrtle rust to see what’s susceptible,” he says.

Plant & Food Research plant pathologist Grant Smith, another of the key researchers working on the project, has worked in Australia helping with their response to myrtle rust and now oversees the seed collecting in New Zealand.

“Right now, what we are trying to do is get enough science data so we can make some decisions in 18 months about how we can respond from a science perspective to myrtle rust in New Zealand – for example, do we have resistance in mānuka that we can exploit in a breeding programme?” he says.

“We are also selecting material to safeguard via germplasm collections or seed banking,” says Dr Smith.

Testing seed resilience to the disease will give researchers information around ‘seed lines’ in New Zealand provinces that show a lot of resilience.

Mānuka and kānuka seeds are the first species to be collected and sent to Australia to be tested. From there, over the next year researchers will collect pōhutakawa and rātā and coordinate with other groups like Scion who are also doing research into this.

“This phase is what I consider to be a ‘secure future options’ to ensure we have options available for decisions we have yet to make,” says Dr Smith.

“In Australia, species extinction across the natural range of the plants is now becoming apparent. Understanding what resistance we have in our native plants, and seed banking those plants now before things get too bad, is essential to ensure we have the plant species available for future options,” he said.

All seed sent to Australia will be destroyed at the end of the project. Extra seed collected during the project is stored in seed banks in New Zealand.

Source: Manaaki Whenua – Landcare Research

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