Understanding the cellular and genetic basis of differences in photosynthetic leaf capacity between Arabidopsis and a close mustard relative Hirschfeldia incana


To use comparative analysis of Arabidopsis and a closely related mustard species, Hirchfeldia incana, to gain an understanding of what determines various aspects of leaf photosynthetic capacity and its environmental plasticity.


Plants show a wide range of differences in the photosynthetic properties of their leaves, particularly regarding the rates of photosynthesis which they can achieve and the ability of photosynthesis to acclimate to environmental conditions such as elevated temperature. To date we understand very little about the genetic basis of these differences, despite the fact that they are great agricultural significance in terms of producing higher yielding crops better adapted to different environmental extremes, particularly elevated temperatures. Arabidopsis thaliana, a small crucifer, is the premier model plant system for genome analysis and gene discovery. However, it generally displays low rates of photosynthesis, and is not adapted to elevated temperatures. In contrast, Hirschfeldia incana, a close crucifer relative, displays a large environmental plasticity, including growth at elevated temperatures and displays the potential for very high rates of photosynthesis. The potential exists to use comparative physiology, cell biology and genomics approaches to understand the molecular basis for these differences.


The project will take two approaches. Comparative physiology and comparative genomics. The physiology and cell biology of Arabidopsis and Hirschfelidia will be characterised under a range of growth conditions, such as light, CO2 and water supply, to define the differences between these two species with regard to acclimations of leaf photosynthetic properties.

Given that the Hirschfeldia genome is only 250 mega bases, and it is closely related to Arabidopsis, comparative genomics approaches will be developed. This will include the use of Arabidopsis gene expression microarrays, the use of new cheap DNA sequencing for EST sequencing and expression analysis, and the use of BAC transformation of Hirschfeldia genome DNA fragments into Arabidopsis to create a set of gain of function mutants.