8 Sep 2022

Fascinating fungi and pesky pathogens

From Our Changing World, 5:00 am on 8 September 2022

The New Zealand Fungarium has a library feel – a quiet and calm room, with just the hum of air conditioning as a backing track. On display in a glass fronted cabinet is a small group of mummified caterpillars on a stick, like weird larval lollipops.

There are some vegetable caterpillar fungi - there are two caterpillars that look mummified, there is fungi growing out of the bottom of them, and a label. They sit on a glass shelf in a cabinet.

Vegetable caterpillar fungi Photo: RNZ

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Ingesting a spore of a particular native fungus causes the caterpillar to change its behaviour, explains Dr Mahajabeen Padamsee, curator of the New Zealand Fungarium. "It goes and buries itself with its head pointing up, and the fungus grows from the top of the head," she says. 

These ‘vegetable caterpillars’ are part of more than 100,000 specimens that make up this collection, a store of dried fungi housed in the Manaaki Whenua – Landcare Research building in the suburb of St Johns in Auckland.  

A large climate-controlled room hosts row upon row of shelves, stacked with large cardboard boxes, themselves filled with envelopes containing dried fungi wrapped in tissue. Some of the specimens are just too large for envelopes, and rest instead in larger boxes or are wrapped in plastic bags to trap their spores.  

Adrienne stands in front of a black Manaaki Whenua banner with New Zealand Fungarium on it, in the storage area. She is smiling, holding a large puff ball fungus within a plastic bag that has a label on the front.

Adrienne Stanton holds a large puff ball, it weighted 8kg when collected. Photo: RNZ

Adrienne Stanton, the collection manager, is responsible for keeping the specimens safe and in good condition, as well as facilitating specimen loans to researchers. Alongside a huge number of native New Zealand fungi, the collection also contains many specimens from across the Pacific.   

The New Zealand Fungarium is used for two main functions – investigating fungal biodiversity and helping biosecurity efforts. It grows each year by about 2,000 specimens. Some are given to the collection by researchers, but many are gathered during the annual Fungal Foray – a multi-day fungi treasure hunt, held in a new area each year with the Fungal Network of New Zealand. 

An important part of the collection consists of ‘type’ specimens – individual specimens chosen to serve as exemplars, the physical basis for naming and describing a species. 

Megan stands on a step in front of a large liquid nitrogen tank - she is wearing a lab coat, thermal gloves, goggles and a mask. She has lifted up the lid of the tank. Bevan stands to the right of the tank also in labcoat, gloves and a face shield, his right hand rests on the tank display. The tank is shiny stainless steel & comes up to Bevan's shoulder height.

Megan Petterson and Bevan Weir in the ICMP Photo: RNZ

Down the corridor from the Fungarium, there's a restricted access room filled with large, stainless-steel tanks. 

“Inside this room we now have every single bacterial plant pathogen that’s ever been described in the world,” says Dr Bevan Weir, the curator of this culture collection, the International Collection of Micro-organisms from Plants (ICMP). 

It’s a collection of about 24,000 living cultures of bacteria, fungi and chromists (genetically distinct from bacteria and fungi, chromists are most closely related to brown algae). Researchers deposit new specimens with the collection, or request them for study, and it also contains type specimens.  

Megan stands in front of a collection of images of different fungi in the foyer area of Manaaki Whenua collection area. She is wearing a black, buttoned blouse and smiling.

Megan Petterson Photo: RNZ

The cultures are in plastic straws inside boxes and kept frozen by use of liquid nitrogen, all under the careful watch of Megan Petterson, the collection manager.  

The ICMP is revealing the hidden bacterial biodiversity of our native plants, but it also has an important role to play in many of New Zealand’s responses to biosecurity threats, including kiwifruit PSA.  

Listen to the full episode to learn more about the New Zealand Fungarium and the ICMP.  

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