The evolution of photosynthetic efficiency

Abstract: Although most plant species conduct the set of reactions required to carry out photosynthesis in a single cell, some species have evolved a way to split the process between two specialized cell types (bundle sheath and mesophyll cells) and in doing so increase photosynthetic efficiency. This spatial division of photosynthesis, known as C₄ photosynthesis, has evolved at least 66 times in both eudicots and monocots and thus represents one of the most remarkable examples of convergent evolution in eukaryotic biology. While insight into the evolution and biochemistry of C₄ photosynthesis has been gained from studying model organisms, it is has been challenging to determine the extent to which molecular mechanisms are shared between C₄ species. In this talk, I will show that transcriptome sequencing across deep phylogeny can be used to determine molecular changes that underpin the independent evolutionary origins of C₄ photosynthesis. I will also discuss insight we have gained through studying the parallel evolution of new genes in multiple independent C₄ lineages. Finally, I will discuss how we have developed mathematical models that allow us to understand and predict the way in which changes in photosynthetic efficiency result in changes in gene and genome evolution. Taken together, these results reveal a previously hidden relationship between metabolism and evolution and provide new insight into how plant evolution is driven by photosynthetic efficiency.

Host: Ian Graham