Green is a color that’s almost universally associated with plants – for good reason. The chlorophyll green pigment is essential for the ability of plants to generate food; but what if they don’t have enough?
New work from Carnegie, Michigan State University and the National Research Institute for Agriculture, Food, and the Environment in France reveals the complex and interrelated nutritional responses that underlie a condition life threatening low chlorophyll called chlorosis associated with anemic and yellow appearance. Their findings, published by Nature Communication, could usher in more environmentally friendly farming practices – using less fertilizer and less water resources.
Photosynthesis is the complex biochemical process by which plant cells convert energy from the sun into chemical energy, which is then used to fix carbon dioxide from the atmosphere into sugar molecules. It occurs inside organelles of highly specialized plant cells called chloroplasts.
Nutrients accumulate in chloroplasts and are essential for their optimal functioning. The research team – led by Hatem Rouached from MSU and including Sue Rhee from Carnegie, Hye-In Nam, Yanniv Dorone, Sophie Clowez and Kangmei Zhao – have shown that a balance between iron and phosphorus is necessary to prevent chlorosis. The project was started when Rouached was a visiting scholar at Carnegie de France, which was made possible in part by At Brigitte Berthelemotgenerous support to promote Franco-American research collaboration.
“For a long time, experts thought that low iron was the only cause of chlorosis, and farmers often applied iron to combat yellowing leaves,” Rhee explained. “But recent work has shown that other nutrients play a role in causing this anemic reaction.”
To better understand what makes leaves chlorotic, the researchers decided to look at the response to several nutrients together rather than one at a time.
They found that plants with iron deficiency-induced chlorosis would turn yellow and photosynthetic activity would be affected, as expected. However, when the nutrient phosphorus was also removed, the leaves of the plant began to accumulate chlorophyll and turned green again.
The explanation for this unexpected response lies in the signaling between the chloroplast, where photosynthesis occurs, and the nucleus of the cell, where its genetic code is stored.
Interdisciplinary analyzes have indicated that the ability of the nucleus to regulate gene expression in response to low iron content depends on the availability of phosphorus. This kind of complex layering of nutritional responses shows that there is still a lot to learn about these communication channels between these two crucial plant organelles.
The team’s findings could have implications for the resilience of food crops, especially crucial in a changing climate.
“We need to rethink the management of fertilizers, for example,” Rouached concluded. “If we take actions that ignore how nutrients interact with each other, we are potentially creating conditions that put plants in failure. It is essential that we correct this thinking by going from there. ‘forward for the benefit of food production around the world. “
This work was funded in part by the Institut National de la Recherche Agronomique – Montpellier – France, AgreeenSkills Plus, Michigan State University, the Carnegie Institution for Science, Brigitte Berthelemot, the US National Science Foundation, and the US Department of Energy, Bureau of Science Bureau of Biological and Environmental Research, Genomic Sciences Program.