Biotech Updates

Researchers Discover Reason Behind Switchgrass' Summer Photosynthesis Shutdown

February 1, 2023

Bales of switchgrass at a Great Lakes Bioenergy Research Center biofuels scale-up site at Michigan State University’s W.K. Kellogg Biological Station Long-Term Ecological Research site. Photo Source: J. E. Doll/Michigan State University

Researchers at Michigan State University led by Assistant Professor Berkley Walker have solved a puzzle that could unlock the full potential of switchgrass as a low-cost and sustainable biofuel crop. In a paper in the journal Frontiers in Plant Science, Walker's team revealed why switchgrass stops performing photosynthesis during its growing season in the middle of the summer, limiting its biofuel yields.

Walker and his team discovered the explanation in switchgrass rhizomes, the little knobby structures that live among plant roots and store food in a starch form to help plants survive winter. The starch in the switchgrass rhizomes is made from the sugars produced by photosynthesis. Once the rhizomes are full of starch, they signal the plant to stop making sugars and adding biomass through photosynthesis.

Walker said that the data shows that the plants do photosynthesis in the summer to save carbon for the winter. As soon as they have enough, they shut down. The team is now working on a better understanding of the molecular machinery that coordinates this photosynthesis shutdown in switchgrass, which also occurs in other perennials. This knowledge could reveal clues about how to override the photosynthesis shutdown and may prove handy for biofuel crops beyond switchgrass.

For more details, read the article in MSUToday.

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