Capitol News

Italy's Phlegraean Fields, known for its volcanic activity and acidic hot springs, is home to microorganisms that thrive in extreme conditions. Researchers at Michigan State University (MSU) are studying these organisms, particularly an alga called Cyanidioschyzon merolae (C. merolae), to understand how it survives and photosynthesizes in such an environment.

A new study published in Plant Physiology by the MSU-DOE Plant Research Laboratory and the Walker lab, in collaboration with the Shachar-Hill lab from the Department of Plant Biology, focuses on C. merolae's unique ability to perform photosynthesis under harsh conditions. This research could help scientists improve or better understand photosynthesis, a crucial process for life on Earth.

"Science has only described a narrow slice of how nature has dealt with the same challenges, but in different ways," said Berkley Walker, principal investigator of the study. The paper "did a great job of determining that the way we commonly see something being done is not the way it has to be done."

The study examines C. merolae's carbon-concentrating mechanism (CCM), which enhances photosynthesis efficiency by positioning carbon dioxide where it's most needed. While CCMs are well understood in plants, they have been characterized for only a few algae species.

"C. merolae is a very simple organism, so it doesn’t have all the structures and abilities that people typically associate with how a carbon-concentrating mechanism works," said Anne Steensma, graduate student and co-first author of the study. "Our paper gets at what the... basic features that you need to build a carbon-concentrating mechanism are."

Researchers used mathematical models developed with collaborators from MSU's Department of Statistics and Probability to simulate C. merolae's behavior. "A big challenge in this study was figuring out how to make sense of how the many different parameters we were plugging into our model worked to interact with each other," said Joshua Kaste, co-first author alongside Steensma.

The model allows researchers to test new conditions and observe potential responses from C. merolae by altering parts of its CCM model. This helps identify essential components of the algae's CCM.

"This shows us the 'minimal path forward' for engineering a carbon-concentrating mechanism," said Walker, who also serves as an associate professor in PRL and the Department of Plant Biology. "The other way to look at it is that maybe we can improve this simple carbon-concentrating system in C. merolae and achieve even greater growth under the extreme environments that it lives under."

Funding for this research came from several sources including grants from the United States Department of Energy (DOE), National Institutes of Health, National Science Foundation Research Traineeship Program, and others.