Researchers create 3D images of C4 plant cellular components

A team from the University of Illinois has quantified the plant cell properties in two C4 species, including cell shape, chloroplast size, and distribution of cell-to-cell connections called plasmodesmata, providing information that can change how people model photosynthesis thanks to their 3D reconstructions.

"Our motivation for this project was to provide critical missing baseline information about C4 plant cell structure," said Moonsub Lee, a postdoctoral researcher at Illinois who, along with Ryan Boyd, led this work for a research project called Renewable Oil Generated with Ultra-productive Energycane (ROGUE). "We quantified a lot of information about the different types of cells involved in C4 photosynthesis that we believe will reduce gaps in understanding."

This work is part of ROGUE, a research project that aims to create an abundant and sustainable supply of oil that can be used to produce biodiesel, biojet fuel, and bioproducts with support from the U.S. Department of Energy. Much of ROGUE's work focuses on two C4 plants, energycane and miscanthus. Lee and his colleagues believe by quantifying cellular structures they can improve modeling and eventually, production.

Published recently in New Phytologist, their work "Exploring 3D leaf anatomical traits for C4 photosynthesis: chloroplast and plasmodesmata pit field size in maize and sugarcane," shows detailed structures, opening the door for more analysis than was possible with previous 2D images. Their findings extend current perceptions of mesophyll cell shape, finding a more intricate structure than the bundle sheath cell which is closer to a simple cylinder.

"The most exciting aspect of this work to me was the ability to visualize the plasmodesmatal interconnections among the different cell types," said Don Ort, the Robert Emerson Professor of Plant Biology and Crop Sciences at the University of Illinois.

The group plans to work with others on the ROUGE project who have engineered Energycane with larger chloroplasts as a strategy to improve photosynthetic efficiency in dynamic light.

"This work was our initial attempt at 3D quantification and visualization of C4 plant structures, said Lee. "The images we were able to observe with these microscopy techniques have facilitated new ideas and questions that we are excited to explore."