Computer modeling of plants’ carbon sequestration could open up new approaches to increasing crop yields
UNIVERSITY PRINCETON
A new study provides a framework for promoting plant growth by incorporating a strategy adopted from a fast-growing species of green algae. The type of algae, called Chlamydomonas rehardtii, contains an organelle called a pyrenoid that speeds up the conversion of carbon that algae take up from the air into a form that organisms can use to grow. In a published study May 19, 2022 in the magazine Natural plantsresearchers at Princeton University and Northwestern University used molecular modeling to identify the pyrenoid features most important for enhanced carbon fixation, and then mapped how this function could be engineered for plants.
This is not just an academic exercise. For many people today, the majority of food calories come from crops that were domesticated thousands of years ago. Since then, advances in irrigation, fertilization, animal husbandry, and the industrialization of crops have helped feed a growing human population. However, for now, only incremental benefits can be harnessed from these technologies. Meanwhile, food insecurity, already at crisis levels for much of the world’s population, is projected to worsen as a result of climate change.
New technology can reverse this trend. Many scientists believe that pyrenoid algae bring about such an innovation. If scientists can create a pyrenoid-like ability to concentrate carbon in plants like wheat and rice, these important food sources could boost their growth.
“This work provides clear guidance on engineering a carbon-concentration mechanism in plants, including major crops,” Martin Jonikasa senior author of the study who is an associate professor of molecular biology at Princeton and a Counterpicks at the Howard Hughes Medical Institute.
Chlamydomonas rehardtii achieves carbon fixation by the action of the enzyme Rubisco, which catalyzes the conversion of CO2 into organic carbon.
Terrestrial plants also use Rubisco for carbon fixation, but in most plants Rubisco is only operating at about a third of its theoretical capacity because it cannot access enough CO.2 to work faster. Therefore, much effort has been focused on studying the mechanisms of carbon concentration, especially those found in cyanobacteria and in Chlamydomonas, with the hope of eventually providing this functionality to terrestrial plants. But there is a problem:
“Although the structure of pyrenoid and many of its components are known, important biophysical questions about its mechanism remain unanswered, due to the lack of quantitative and systematic analysis,” co-authors said. Senior fake said Ned WingreenHoward A. Former Princeton Professor of Life Sciences and Professor of Molecular Biology and Lewis-Sigler Institute for Integrative Genes.
To better understand how the pyrenoid carbon concentration mechanism works in algae, Princeton graduate student Chenyi Fei collaborated with Alexandra Wilson, Class of 2020, to develop a computational model of the pyrenoid with the help of co-author Niall Mangaassistant professor of engineering science and applied mathematics at Northwestern University.
Previous work has shown that Chlamydomonas rehardtii The pyrenoid consists of a spherical Rubisco substrate that traverses a blood vessel of membrane-bound projections known as the pyrenoid tubule, and is surrounded by a shell made of starch. It is assumed that CO2 taken from the medium is converted to bicarbonate and then transported into tubes, where it then enters the pyrenoid. An enzyme present in the tube converts bicarbonate back to CO .2, then diffuse into the Rubisco matrix. But is this picture complete?
“Our model demonstrates that this conventional picture of carbon pyrenoid concentration cannot work because CO2 will quickly leak back out of the pyrenoid before Rubisco can process it,” said Wingreen. “Instead, the starch shell around the pyrenoid must act as a diffusion barrier to trap CO .2 in pyrenoids with Rubisco. “
In addition to identifying this diffusion barrier, the researchers’ model pinpointed proteins and other structural features required for CO.2 concentration. The model also identifies nonessential components, which should make engineering pyrenoid function in plants a simpler task. The researchers showed that this simple model of the pyrenoid behaves similarly to the actual organelle.
“The new model was developed by Fei, Wilson and colleagues,” said Alistair McCormick, an expert in molecular physiology and synthetic biology at the University of Edinburgh who worked with the Princeton scientists. is a game changer. learn.
“One of the key findings of this paper, which distinguishes Chlamydomonas McCormick said the mechanism for carbon sequestration from those found in cyanobacteria is that the introduction of active bicarbonate transporters into the body may not be necessary. “This is important because active bicarbonate transport is a key challenge hindering progress in engineering physiological carbon-concentration mechanisms.”
Research, “Pyrenoid-based CO modeling2The centralized mechanism provides detailed information on its operating principles and a roadmap for its engineering for crops,” by Chenyi Fei, Alexandra T. Wilson, Niall M. Mangan, Ned S. Wingreen and Martin C. Jonikas, published in Natural plants.
Funding for this study was provided by the National Institutes of Health, the National Science Foundation, the Simons Foundation, and the Howard Hughes Medical Institute.
JOURNEYS
Natural plants
DOI
RESEARCH METHODS
Simulation / computational modeling
ARTICLE TITLE
Modeling of a pyrenoid-based CO2 concentration mechanism provides insights into its working principle and technical roadmap for plants.
ARTICLE PUBLICATION DATE
May 19, 2022
REPORT REPORT
The authors declare no competing interests.
Related
