biological sciences HONOURs 2014 - The University of Sydney

38 DEVELOPMENT OF
ROOT ARCHITECTURE
Research Interests
Genetics and molecular biology are used in order to decipher
the way in which genes, biochemicals and environment work
together to shape an organism. My philosophy is that scientific
progress at the molecular level comes into its own when
small molecular changes affect the phenotype of the whole
organism. For this reason, my experiments combine a molecular
investigation with work on the whole organism in two ways.
We investigate the effect that small genetic changes have
on the whole organism and we investigate the way in which
phenotypic differences are encoded by the genome.
The particular system used in the lab is the plant Arabidopsis
thaliana. Root architecture (the ratio of branching versus linear
growth) is influenced by both genes and environment. We
aim to understand the contribution of both. Using knockout
mutants, we have identified a series of genes that affect the
way that roots develop.
Honours projects
1. The role of actin in root branching in Arabidopsis thaliana.
Analysis of mutants in the lab has shown that root branching
patterns are altered when the expression of the gene Severe
Depolymerisation of Actin (SDA1) is altered. In this project
Dr Jenny Saleeba
Room 307, Macleay
Building A12
T: (02) 9351 6695
E: jenny.saleeba@sydney.
edu.au
you will cross SDA1 mutants with lines containing mutations in other actin related genes. The
analysis of gene activity and plant root phenotype will be used together to understand how the
expression of SDA1 fits into the coordinated expression of actin pathway genes. You will answer
the question, what steps in gene expression are required to stabilise actin and allow normal root
branching?
2. The role of energy partitioning in root branching in Arabidopsis thaliana. There is a
relationship between the ready availability of the sugar-rich products of photosynthesis and a
high rate of root branching in A. thaliana. In recent experiments we have discovered that the
expression of the AT3G49160 gene, encoding pyruvate kinase, changes the degree to which
roots branch. It is hypothesised that pyruvate kinase affects root branching via the peturbation
of sugar homeostasis in the plant. In this project you will investigate the way in which the
pyruvate kinase gene fits with the pathways of other known gene products in the development
of roots.