Honours supervisors and projects

Professor John Hamill

Plant molecular genetics

Telephone: 9905 3850
Email: john.hamill@sci.monash.edu.au

Note : All projects will involve practical experience in general and plant molecular genetics; production of transgenic plant tissues and associated biochemical analysis.  Projects will involve collaboration with Drs Alan Neale, Ros Gleadow, Cecilia Blomstedt, Amanda Walmsley and/or Diane Webster (Burnet Institute) as appropriate. Although some of the topics may appear rather ‘chemical’ in nature, a strong chemistry background is not required as we will be focussing on the theoretical and functional genetic aspects of the relevant projects. Collaborators located in external labs will undertake any complex chemical analysis that is required. Pdfs of relevant recent papers from JDH lab are available via http://www.biolsci.monash.edu.au/staff/hamill.  Additional pdfs of relevant papers are available from JDH upon request

1. Molecular genetic controls of defensive pyridine alkaloid synthesis in plants

As sessile, nutrient and water-rich organisms, many plants synthesise nitrogen-rich toxic alkaloids which protect their foliage from being devoured by hungry predators. Many alkaloids are also of medicinal value due, in no small part, to their pharmacological effects on cellular and organ physiology when ingested by humans. We are interested in the molecular controls governing the capacity of Solanaceous species to make alkaloids that are derived from nicotinic acid. (Cane, Hamill et al., 2005; Chintapakorn and Hamill 2007 ). An Honours project in this area in 2008 will extend work undertaken by PhD student Kath de Boer and recent Honours students Jessie Lye and Felicity Edwards to functionally characterise one or more genes (regulatory and structural) that we have identified which may facilitate wound-induced alkaloid synthesis in Nicotiana . Applied aspects of this project may include introducing capacity for natural insecticide synthesis into non-food plants (e.g. timber or fibre crops) or the elevation of nicotinic acid (niacin – vitamin B3) levels in vegetables with the possibility of long term health benefits – particularly in the elderly and/or those with increased risk of developing cognitive disorders (e.g. Morris MC et al. [2004] J. Neurol Neurosurg Psychiatry 75 : 1093 – 1099)

2. Production of a plant derived oral vaccines in plant hairy roots cultured in vitro

Currently there is much interest in the potential of transgenic plants as a production system for oral vaccines against infectious diseases. Particularly attractive features of such plant derived vaccines are the ease and cost effectiveness of production in tissues that can be readily freeze dried and transported at ambient temperature. A reduced risk of contamination with animal pathogens is an additional attractive feature of plant-derived vaccines (Webster et al., 2005 Vaccine 23 : 1859 – 1868). In this project we will continue work undertaken by Hons student Giorgio deGuzman in 2006 to produce high levels of LTB protein in hairy root cultures of non-toxic plants such as Petunia and Tomato. We will explore the use of various promoters and their potential for inducting high levels of vaccine protein in cultured root tissues simply by adding natural, non-toxic and cheap chemicals such as ethanol and the plant hormone methyljasmonate.

3. Regulation and functional analysis of genes important in controlling tolerance to extremes of biotic stress in higher plants

In recent years Australian agriculture has suffered from the effects of serious drought and salinity and, if recent CSIRO climatic predictions are even partially correct, these problems will become increasingly acute in the years ahead. Similar problems will also affect agricultural productivity in many parts of the world and will produce significant challenges for global food security. The study of plants that have evolved the capacity ability to survive and grow in extreme environments may provide practical solutions for agriculture in future years and such plants are a potential source of genes to enable the breeding of plants better suited to the increasingly harsh agricultural environments that crops will have to be grown in. We have recovered a number of novel genes which are activated in grass plants from desert regions of Southern Africa in response to severe drought stress and are characterising these genes with the aim of deducing how their encoded protein products may contribute to cellular drought and salt tolerance. (Le, Neale, Hamill et al .2007). An Honours project in this area will involve a molecular and functional analysis of selected genes and their associated regulatory DNA sequences. Gene transfer experiments will investigate the effectsof expressing specific regulatory gene and reporter gene constructs from desiccation- and salt-tolerant grass species in cells of model species such as Arabidopsis and rice to assess functionality and the extent to which abiotic stress tolerance can be increased via gene transfer.

4. Legume genes to protect crop plants from infection by Striga plant parasites.

The genus Striga contains a number of parasitic weed species which infect many crop plants throughout the world and are responsible for huge losses in agricultural productivity in the developing world – particularly sub-Saharan Africa. Recent studies in the lab of Prof John Pickett (Rothamsted Research Institute UK) indicate that the roots of legumes in the genus Desmodium can produce and secrete water-soluble metabolites into the soil that can reduce or even prevent infection of crop plants by Striga species (e.g. Tsanuo et al., Phytochem 64 : 265 – 273). We are collaborating with the lab of Prof Picketts and have produced hairy root cultures of two Desmodium species which will enable the identification and functional testing of relevant genes that are involved in production of these protective metabolites. Ultimately, incorporation and over-expression of such genes in crop plants and/or companion nitrogen-fixing legumes may provide high levels of protection against infection by the parasite so leading to productivity gains for impoverished farmers in sub-Saharan Africa.