Researchers Discover Pathway that Helps Clean Up Toxic Chemicals from Plant Cells

Researchers from Michigan State University-Department of Energy Plant Research Laboratory have discovered a pathway in a plant process that could help farmers grow more crops, particularly in places where harsh, high-light stresses plants.

The pathway complements the main workflow of photorespiration, indicating that the process is more flexible than it seems. Xiaotong Jiang and colleagues at Jianping Hu's lab discovered that under stressful conditions, plants take a different approach. In a previous study, Jiang experimented with a lab-made mutant of Arabidopsis thaliana. The mutant could not produce a key photorespiration enzyme, hydroxypyruvate reductase 1, or HPR1. When grown in a high-light environment, those plants struggled to keep pace with non-mutant plants. The team introduced random mutations to the broken HPR1 and observed which plants improved. They then identified the genes that could make up for the faulty HPR1 enzyme.

Researchers discovered that deactivating the enzyme glyoxylate reductase 1 (GLYR1) triggers a cytosolic glyoxylate shunt, a parallel pathway. Normally, GLYR1 converts glyoxylate to glycolate. However, when GLYR1 is inactive, glyoxylate accumulates and is instead converted to hydroxypyruvate and then glycerate by HPR2, an enzyme related to HPR1. These two enzymatic steps are similar to those in the main photorespiration process but occur in the cell's cytosol, unlike the peroxisome-located steps of standard photorespiration.

For more details, read the article on the Michigan State University website.