Plants use different types of photosynthesis, some more efficient than others. While most use C3 photosynthesis, including the common sunflower, a few use C4 photosynthesis, such as maize and sugar cane, which is more efficient in hot and dry environments. “This is why the GAIN4CROPS project aims to introduce C4 traits into C3 plants to boost photosynthesis and increase crop yields in these environments,” explains Tianshu Sun.
The genetics behind a more efficient photosynthesis
As a postdoctoral research associate at the Molecular Physiology group of Cambridge University’s Department of Plant Sciences, Tianshu has been studying the transition from C3 to C4 photosynthesis, “which involves a complex mixture of anatomical, biochemical and, crucially, genetic changes,” she explains. She is researching how plants compartmentalise genes into different cell types to optimise photosynthesis. “Are there genes or functions—in certain cells—that are only found in C4 species?” she asks, “That’s the question we want to answer. That’s what I’m doing right now.”
The cell-specific genetic information from these studies will eventually be used to test if and how C4 traits could be induced in sunflowers.
Model plants as a steppingstone
Although the target crop of the project is the common sunflower, Tianshu has been studying species in the Flaveria group—sometimes called yellow tops—as a springboard for exploring cell-specific gene expression. “Species in the genus Flaveria are closely related to the common sunflower and may share a genetic background, so it is more likely that the knowledge gained from experiments in Flaveria will apply to sunflowers,” she explains.
Despite being a small genus, Flaveria has C3, C4 and even C3-C4 intermediate species, making it an excellent model to study how plants evolved from C3 to C4.
Tianshu adds that working with teams from the diverse GAIN4CROPS consortium helped her gain a fresh perspective on her work. “When you’re working on genomics, sometimes you dive too deep into your data and often don’t have a chance to validate your ideas,” she admits. “Being part of the GAIN4CROPS consortium is very stimulating and allows me to witness ideas in action!”
Indeed, they will collaborate with the team at the Heinrich-Heine-Universität Düsseldorf to test the identified genes in some plants: “We want to test first in the model plant Arabidopsis, which has a short life cycle and is easy to modify. If we see something promising, we can then move on to sunflowers.” says Tianshu. “Plants have complex genomes, so it’s important to have a solid base before taking the next step. It’s a long journey, but we have a good start.”