A project undertaken at Royal Botanic Gardens Victoria, and supervised by Noushka Reiter
Orchids are some of Australia’s most iconic wildflowers, yet they contain more endangered species than any other plant family. Orchids are unique in that they require an association with a mycorrhizal fungus to germinate and reach the seedling stage, an association that is retained into adulthood. As such, understanding their mycorrhizal associations represents a key challenge for orchid conservation programs that involve ex situ preservation and growing plants for reintroduction. Here, we focus on Thelymitra (the Sun-orchids), a diverse but highly endangered group of Australian orchids, which includes many vividly coloured species, such as the Queen of Sheeba. For a set of Sun-orchid species strategically sampled based on evolutionary relationships and threat status, we plan to isolate their mycorrhizal fungi and experimentally confirm function via germination tests.
We will test if rare species and phylogenetically unique species share their fungi with more common Sun-orchids, which could therefore provide a source of fungi for conservation programs but also provide a guide to the geographic range and habitat of the fungi. Based on previous work on orchid-associating fungi in Australia, it is almost certain that our work will lead to the discovery of numerous species of fungi new to science. Beyond the lifetime of this project, our work will leave a legacy of a permanent ex situ collection of fungi that can be used to germinate Sun-orchids for conservation projects, knowledge of the necessary fungal species to support germination, and addition of precious seed to conservation seed banks.
