Plants from the Solanaceae family include important crop species such as potato, tomato, capsicum and eggplant. Less widely known are Australian native Solanum species that have been used by Indigenous Australians for probably thousands of years for food and other uses. In central Australia the Bush Tomato or Desert Raisin (Solanum centrale) is one of a number of Solanum species that are collected as bush tucker by Aboriginal peoples.
In recent years, there has been commercial use of Bush Tomato as an ingredient in food products such as chutneys and sauces and spice sprinkles. Demand for the product has outstripped bush harvest supply and the CRC for Remote Economic Participation (CRC-REP) is interested to determine if Bush Tomato can be developed as a cultivated species for horticultural production and become a model crop for other indigenous Native Food plants. To promote the growth of the fledgling Bush Tomato cropping industry, CRC-REP have funded a research project (Plant Business) to develop the horticultural, fruit quality and genetic understanding of bush tomato. To date genetic analyses of Bush Tomato have indicated that there is a high degree of genetic diversity in the gene pool (Collins, 2002) which bodes well for future breeding. DNA markers for population genetic studies have been developed for this species (Waycott et al., 2011).
There had been reports that the fruit may be toxic especially if it is unripe but chemical and toxicological information is scarce. Aplin and Cannon (1971) reported high to moderate levels of alkaloid content in some species of Solanum. Collins (2002) reported the presence of steroidal alkaloids in immature fruits of S. centrale but not in the mature fruit. Hegarty et al (2001) reported the presence of oxalic acid, trace level of saponins and the presence of the solanidine alkaloid β2-chaconine with the highest level detected in the green fruit. This suggests the need to monitor the alkaloid content of the commercial produce for quality control purposes and ascertain food safety.
At Southern Cross Plant Science we are developing methods to study aspects of the genetics and chemical makeup of the Bush Tomato. This work will be used in the future breeding of this species for selection of improved cultivars for commercial production in ways acceptable to Aboriginal people. It is hoped that Aboriginal communities will be involved in commercial production and/or benefit from the development of new varieties by potential licensing agreements in the future.
Current research interests include:
- Developing a DNA test to distinguish Solanum centrale plant material from other Solanum species
- Examining genetic differences between Bush Tomato populations to determine how distinct populations are from one another
- Discovering genetic markers which can distinguish between individual varieties of Bush Tomato
- Looking at the variable level of ploidy (number of copies of homologous chromosomes) found in S. centrale to determine if populations are really mixtures of several species of different ploidy
- Identifying the phytochemical variation within bush tomato
- Developing a method to determine levels of glycoalkaloids in bush tomato
- Cooperative Research Centre for Remote Economic Participation (CRC-REP)
- Aboriginal Communities of the arid region of Northern Territory (approx. six locations)
- University of New England
- RemoteBiz Pty Ltd
- Ninti One Pty Ltd
- Desert Garden Produce Aboriginal Corporation
- Kungka's Can Cook
- Robins Foods Pty Ltd
- Northern Territory Government
This area of research is new at SCPS, with research projects in genetics and chemical analyses starting in January 2012. SCPS contributes to the "Plant Business" of CRC-REP which includes:
- informing decisions in other parts of the Plant Business project
- scientific publications in plant genetics and phytochemistry of bush tomato
- contributing to informing CRC-REP stakeholders
Delivery of research
Bush Tomato Genetics: Dr Peter Bundock
Bush Tomato Phytochemistry: Profssor Graham King
Plant Business Research Leader: Dr Slade Lee
Some publications on the earlier work carried out on bush tomato include:
Aplin, T.E.H. and Cannon, J.R. (1971) Distribution of alkaloids in some Western Australian plants. Economic Botany, 25:366-380.
Collins, C (2002) A study into the domestication of Solanum centrale, Australian bush tomato. PhD Thesis, University of Adelaide, Waite Campus, South Australia.
Hegarty, M.P., Hegarty, E.E. and Wills, R.B.H. (2001) Food safety of Australian plant bushfoods. RIRDC Publication No. 01/28, Project No. AGP-1A.
Menda, N., Buels, R.M., Tecle, I., Mueller, L.A. (2008). A community-based annotation framework for linking Solanaceae genomes with phenomes. Plant Physiology 147(4):1788-1799.
Waycott M, Jones BL, Dijk JK, Robson HL and Calladine A (2011) Microsatellite markers in the Australian desert plant, Solanum centrale (Solanaceae). American Journal of Botany 98(4):e81-3.