biological sciences HONOURs 2014 - The University of Sydney
biological sciences HONOURs 2014 - The University of Sydney
biological sciences HONOURs 2014 - The University of Sydney
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42<br />
PLANT MOLECULAR<br />
BIOLOGY<br />
Research Interests<br />
My laboratory uses molecular biology and cell biology techniques<br />
to study a range <strong>of</strong> topics including the legume-rhizobia symbiosis,<br />
long distance signaling in plants and plant food allergens.<br />
<strong>The</strong> Legume-Rhizobia Symbiosis: To produce our food, the crops<br />
we grow need to have enough nitrogen. This nitrogen is usually<br />
supplied as an expensive, chemically synthesised fertilizer.<br />
Legumes are plants that are able to combine with bacteria,<br />
termed rhizobia, to form an association (symbiosis) where<br />
nitrogen from the air is converted to a form that can be used<br />
by plants. This means they can grow without nitrogen fertilizer<br />
and also that they can leave nitrogen in the soil for the next crop<br />
grown, reducing the reliance on fertilizers.<br />
<strong>The</strong> rhizobia are enclosed by a membrane that the plant<br />
synthesises, inside a new organ on the roots <strong>of</strong> the plant called<br />
a nodule. We are studying the composition, development and<br />
function <strong>of</strong> the membrane (the symbiosome membrane) as<br />
it is the interface between them and probably controls how<br />
efficiently nitrogen is fixed.<br />
Dr Penny Smith<br />
Room 239A, Macleay<br />
Building A12<br />
T: (02) 9036 7169<br />
E: penny.smith@sydney.<br />
edu.au<br />
Honours projects<br />
1. Which plant genes are expressed in cells infected by rhizobia? Find out how rhizobia modify<br />
plant gene expression. You would use laser capture micro-dissection to isolate cells infected by<br />
rhizobia, isolate RNA and then use RNAseq to compare the expression with that <strong>of</strong> non-infected cells.<br />
2. Metal transporters on the symbiosome membrane and their role in symbiotic function.<br />
Investigate how reducing the expression <strong>of</strong> one symbiosome membrane transporter changes the<br />
expression <strong>of</strong> the other transporters. Investigate this using RNAi, real-time qPCR, proteomics<br />
and/or metabolomics.<br />
3. <strong>The</strong> role <strong>of</strong> nutrient transporters in regulating efficiency <strong>of</strong> nitrogen fixation. What happens<br />
when you reduce the expression <strong>of</strong> particular transport proteins on the symbiosome membrane?<br />
Use gene silencing to reduce expression <strong>of</strong> your candidate transporter and investigate how this<br />
affects the nitrogen fixation.<br />
4. Characterisation <strong>of</strong> the symbiosome space. <strong>The</strong> symbiosome space is the region inside<br />
the symbiosome membrane that surrounds the bacteroid membrane. This project is a detailed<br />
proteomic study <strong>of</strong> the symbiosome space. You would then choose a protein for further molecular<br />
characterisation to determine if it is essential for the symbiosis.<br />
5. Other possible projects: a) Molecular characterisation <strong>of</strong> symbiosome development.<br />
b) Studying changes in the symbiosome membrane proteome throughout development using<br />
quantitative proteomics.