This research focuses on the unique and agriculturally significant mutualism known as the legumerhizobia
symbiosis. This interaction enables a type of soil bacteria termed rhizobia to fix di-nitrogen
from the atmosphere into a nitrogen form that a legume plant can use for growth and development.
In return, the plant provides carbohydrates to the bacteria. This interaction is critical to agricultural
systems to increase legume crop yields and improve soil health. Interestingly, the plants
sophisticated innate immune system which is crucial for defence against microbial pathogens
appears to be activated during early stages of this beneficial interaction. Moreover, recent evidence
has shown that certain defence genes can determine which rhizobia strains - varying from highly
efficient, mutualistic strains, to pathogenic ones - are able to enter into symbiosis with the plant
host. Throughout my PhD studies I have focused on investigating several novel gene candidates
which structurally represent defence genes, but via transcriptomic analyses appear to be important
for this mutualistic relationship. These investigations implement molecular, physiological and
bioinformatic approaches to functionally characterise these newly identified gene candidates.
Findings from this research will improve our understanding of how the plant immune system
regulates the legume-rhizobia symbiosis, which can then be optimised to this highly important
interaction in agriculture.

Funding: Recipient of the UQ graduate school scholarship (UQGSS)

Project members

Estelle Grundy

PHD candidate
School of Agriculture and Food Sustainability