What will a three-degree-warmer world look like? How will plants fare in more extreme weather conditions? When experiencing stress or damage from various sources, plants use chloroplast-to-nucleus communication to regulate gene expression and help them cope.

Now, Salk Institute researchers have found that GUN1–a gene that integrates numerous chloroplast-to-nucleus retrograde signaling pathways–also plays an important role in how proteins are made in damaged chloroplasts, which provides a new insight into how plants respond to stress. The paper was published in the Proceedings of the National Academy of Sciences (PNAS) on April 15, 2019, and may help biologists breed plants that can better withstand environmental stressors.

“Climate change holds the potential to affect our food system dramatically. When plants are stressed, like in a drought, they produce lower crop yields. If we understand how plants respond to stress, then perhaps we can develop a way to increase their resistance and keep food production high,” says Salk Professor Joanne Chory, director of the Plant Molecular and Cellular Biology Laboratory and senior author of the paper.

In plant cells, structures called chloroplasts convert energy from sunlight into chemical energy (photosynthesis). Normally, the nucleus of the cell transmits information to the chloroplasts to maintain steady energy production. However, in a stressful environment, chloroplasts send an alarm back to the cell nucleus using retrograde signaling (creating a chloroplast-to-nucleus communication feedback loop). This SOS prompts a response that helps regulate gene expression in the chloroplasts and the nucleus to optimize energy production from sunlight.

Source: Plants are also stressed out