Enzymes key to why some crops can weather extremes better than others
Sorghum, sugarcane, millet and maize use a form of photosynthesis called C4 that made them more efficient at transforming carbon dioxide, light and water into sugars, the study found.
“They do this by taking up carbon dioxide from the air and concentrating it in specialised cells deep in the leaf,” said lead researcher Hugo Alonso-Cantabrana, of the Australian National University.
Meanwhile, wheat and rice—known as C3 plants—use the oldest form of photosynthesis, which gives them a disadvantage in high temperatures and low rainfall, Alonso-Cantabrana’s team reported in a paper published in the Journal of Experimental Botany.
“C4 plants can capture carbon dioxide from the air while losing less water from their leaves, but little is known about what determines the efficiency of this process,” said co-researcher Hannah Osborn.
To investigate the process, the team studied the role of carbonic anhydrase (CA), the first enzyme that carbon dioxide encounters in the leaf of a model C4 plant, Setaria viridis, also known as green millet.
“This enzyme is vital for C4 photosynthesis as it helps carbon dioxide from the air to dissolve quickly into the liquid of the cell,” Osborn said.
“This is the first time that we have been able to transform this model C4 plant to have less of the CA enzyme and look at the effects on photosynthesis and water loss.
“We think that under adverse conditions such as drought or high temperatures, having a lot of this enzyme could be advantageous for the plant.”
The team will continue the research to test the role of the enzyme under extreme environmental conditions.