How fast-growing algae could enhance growth of food crops

A new study provides a framework to boost crop growth by incorporating a strategy from a fast-growing species of green algae. The pyrenoid is an organelle found in the Chlamydomonas reinhardtii that speeds up the conversion of carbon, which the algae absorb from the air, into a form that the organisms can use for growth. In a study published in the journal Nature Plants in May of 2022, researchers at Princeton University and Northwestern University used modeling to identify the features of the pyrenoid that are most critical for enhancing carbon fixation, and then mapped how this function could be engineered into crop plants.

This is more than just an academic exercise. Crop plants have been domesticated thousands of years ago. The industrialization of farming has helped feed the growing human population. Incremental gains can only be obtained from these technologies. Changing climate is predicted to make food insecurity worse, already at crisis levels for much of the world's population.

This trend could be reversed by new technology. Many scientists think the algal pyrenoid offers an innovation. If scientists can engineer a pyrenoid-like ability to concentrate carbon into plants such as wheat and rice, these important food sources could experience a major boost to their growth rates.

The work provides clear guidance for engineering a carbon-concentrating mechanism into plants, including major crops, according to the senior author of the study.

The action of the enzyme Rubisco leads to the conversion of CO 2 into organic carbon by chlamydomonas reinhardtii.

Terrestrial plants use Rubisco, but it only works about a third of its theoretical capacity because it can't access enough CO 2 to operate faster. The hope is that the carbon-concentrating mechanisms found in cyanobacteria and in Chlamydomonas will eventually be used for crop plants. There is a problem.

While the structure of the pyrenoid and many of its components are known, key biophysical questions about its mechanism remain unanswered due to a lack of quantitative and systematic analysis.

To gain insights about how the pyrenoid carbon-concentrating mechanism works, a graduate student and undergraduate collaborated with a professor to create a model of the pyrenoid.

Prior work shows that the Chlamydomonas reinhardtii pyrenoid consists of a spherical Rubisco matrix and a sheath made of starch. It is thought that CO 2 taken up from the environment is converted into bicarbonate and then enters the pyrenoid. The Rubisco matrix is created by the conversion of bicarbonate into CO 2 by the tubules. Is this picture complete?

Wingreen said that the picture of the pyrenoid carbon-concentrating mechanism could not work because CO 2 would leak back out of the pyrenoid before Rubisco could act on it.

The model identified other structural features needed for CO 2 concentration. The model identified components that should make engineering pyrenoid function simpler. The simplified model of the pyrenoid behaves the same as the actual organelle.

The new model developed by Wilson and colleagues is a game-changing discovery, according to an expert in plant biology at the University of Edinburgh who was not involved in the study.

The paper shows that the carbon-concentrating mechanism of the Chlamydomonas is different from that of the cyanobacteria.

More information: Niall Mangan, Modelling the pyrenoid-based CO₂-concentrating mechanism provides insights into its operating principles and a roadmap for its engineering into crops, Nature Plants (2022). DOI: 10.1038/s41477-022-01153-7 Journal information: Nature Plants Citation: How fast-growing algae could enhance growth of food crops (2022, May 19) retrieved 19 May 2022 from https://phys.org/news/2022-05-fast-growing-algae-growth-food-crops.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.