Improving photosynthesis: the red algae story

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Yu Zhou is a PhD student who studies how plants transform carbon from the atmosphere into biological matter (e.g. roots, leaves, fruits), by fixing carbon dioxide (CO2) during photosynthesis. The main enzyme in charge of this important task is Rubisco, the most abundant protein on Earth.

However, not all Rubiscos are equal. Some, like the ones found inside green plants, are inefficient as they only poorly distinguish between CO2 and oxygen (scientists call this having a low CO2 specificity). Other Rubisco, like the ones found in some red algae, have evolved to be two-fold better at distinguishing CO2 from oxygen, which makes this type of Rubisco much more efficient at fixing carbon.

PhD student Yu Zhou is part of a team looking to replicate the properties of these super-efficient red algae Rubiscos in crops as a way improve their photosynthesis, growth and yield. They have found that one of the best ways to generate better Rubiscos is by using directed evolution. This method provides a way to replicate millions of years of evolution in just a matter of days in the lab, enabling them to rapidly identify the structural changes needed to improve Rubisco activity.

During her PhD, Yu Zhou used this method for first time on a Rubisco related to that found in red algae.

“We found a mutation in our model red-type Rubisco that improved both its CO2-fixation rate and its CO2 specificity and we are continuing the process to evolve even better versions of the enzyme. We think that in the future, we will be able to transfer these Rubiscos into food crops such as maize, wheat and rice to improve food production and feed the growing world population, ” says Yu.

This research was published last October, 2019 here:

Zhou, Y and Spencer Whitney. Directed Evolution of an Improved Rubisco; In Vitro Analyses to Decipher Fact from Fiction. Int J Mole. Scie  2019, 20 (20)5019 Read article