Jeremy Bougoure - PhD Student

School of Plant Biology (M090)
University of Western Australia
35 Stirling Highway
Crawley  WA  6009
AUSTRALIA

telephone     +61 8 6488 7923
fax               +61 8 6488 7925
email            bougoj01@student.uwa.edu.au

Bachelor of Science (1st Honours) - University of Southern Queensland

PhD Thesis - The role of mycorrhizal fungi in nutrient supply and habitat specificity of the rare myco-heterotrophic underground orchid, Rhizanthella gardneri Rogers.

Supervisors: Dr Pauline Grierson (UWA), Dr Mark Brundrett (UWA), Dr Martha Ludwig (UWA), Mr Andrew Brown (DCLM), Prof Krishnapillai Sivasithamparam (UWA), Dr Kingsley Dixon 
Funding: ARC-Linkage grant (ARC-LP 0454276). 
Commenced: April 2004

The underground orchid (Rhizanthella gardneri Rogers) is a unique Australian plant that lives and flowers underground in a few scattered locations in the wheat-belt of WA. Limited to less than 50 known surviving mature plants, this fascinating and unique species cannot acquire energy via photosynthesis (i.e. it is fully subterranean) and is therefore myco-heterotrophic. As such, it is assumed that its survival is entirely dependent on a specific relationship formed between the mycorrhizal fungus Thanatephorus gardneri and Broom Bush (Melaleuca uncinata). Preliminary investigations have shown that M. uncinata and R. gardneri are linked via a single Rhizoctonia type fungal species (T. gardneri) capable of forming both ectomycorrhizas and orchid mycorrhizas.

Although myco-heterotrophy is assumed, it has not been confirmed that there is transfer of photosynthate and nutrients from M. uncinata to R. gardneri via the fungus T. gardneri. Furthermore, the identity of this fungus is unusual and in contrast to all other surveyed myco-heterotrophic orchids that presumably associate with typical homobasidiomycete ectomycorrhizal fungal species.

Objectives

• Investigate nutrient cycling and carbon transfer processes in glasshouse experiments and under field conditions to establish how mycorrhizal fungi supply R. gardneri with minerals and energy in comparison with several West Australian orchids with chlorophyll.

• Gain a better understanding of factors limiting recruitment and survival for R. gardneri.

• Develop means to detect mycorrhizal fungi that associates with R. gardneri in field sites.

• Help to identify the most critical threats to this species in its remaining habitat(s) and identify potential new habitats.

• Assist with field research trials to establish sustainable orchid populations by contributing scientific knowledge, skills and propagated plants for the recovery process.

Exposed flowers of Rhizanthella gardneri taken near Oldfield River, WA. 2004

Publications

Bougoure, J.J. and Dearnaley, J.D.W (2005) The fungal endophytes of Dipodium variegatum (Orchidaceae). Australasian Mycologist 24 (1) 15-19.

Bougoure, J.J., Bougoure, D.S., Cairney, J.W.G. and Dearnaley, J.D.W (2005) ITS-RFLP and sequence analysis of endophytes from Acaianthus, Caladenia and Pterostylis (Orchidaceae) in southeastern Queensland.   Mycological Research. 109 (4) 452-460.

Irwin, M.J., Bougoure, J.J. and Dearnaley, J.D.W. (2007)  Pterostylis nutans (Orchidaceae) has a specific association with two Ceratobasidium root-associated fungi across its range in eastern Australia. Mycoscience 48 231-239

Presentations

Bougoure, J., Brundrett, M. and Grierson, P.F. 2007 Carbohydrate acquisition and transfer mechanisms of the critically endangered mycoheterotrophic Rhizanthella gardneri Proceedings - 4th International Symposium on Physiological Processes in Roots of Woody Plants. Bangor, Wales, 16-20th September 2007 Oral Presentation

Useful Links

Department of Environment and Conservation 
Botanic Gardens and Parks Authority (Kings Park)