Relieving the stress on crop plants
The search for an answer to the role of nitrogen oxide (NO) in plant cells lies in a cell body known as the peroxisome. At the heart of cell metabolism, this organelle is responsible for the production of many signal molecules that are essential for the regulation of plant development. Peroxisomes also play a major role in stress conditions such as when a plant is subjected to xenobiotics - including pollutants, ozone and the heavy metal cadmium. The recent discovery of NO as one of the products of peroxisomes opens up the scope for their importance in plant metabolism. The precise role of NO in the peroxisome context was unclear but the fact that NO is involved in modification of protein in both animal and plant cells made the compound an exciting prospect for research by the EU- No signal project. One of the most significant functions of NO is related to a process called s-nitrosylation. Once proteins have been produced, s-nitrosylation is responsible for changing them and is the key to plasticity in plants whereby they can change their structure and function. The process involves the attachment of NO to a certain amino acid in a protein. As such, NO could be responsible for modulation of protein activity. For the first time, the No signal researchers observed s-nitrosylation in plant peroxisomes and identified six protein targets for this process. The plants were subjected to stresses including salt, the herbicide 2, 4-D and cadmium. The scientists also identified s-nitrosylation in the power house of the cell, the mitochondrion. Plants are subject to many stresses through their development and have evolved a range of resistance mechanisms. Once the biochemistry behind these survival responses is clear, plant breeders can apply them to crop design to avoid loss due to disease and abiotic,non-living chemical and physical factors.
