Engineering stress tolerance in maize

A wide range of environmental stresses (such as chilling, ozone, high light, drought, and heat) can damage crop plants, with consequent high annual yield losses. A common factor in all these unrelated adverse conditions, called oxidative stress, is the enhanced production of active oxygen species (AOS) within several subcellular compartments of the plant. AOS can react very rapidly with DNA, lipids and proteins, causing severe cellular damage. Under normal growth conditions, AOS are efficiently scavenged by both enzymatic and non-enzymatic detoxification mechanisms. Nevertheless, during prolonged stress conditions such detoxification systems get saturated and damage occurs. The main players within the defence system are superoxide dismutases, ascorbate peroxidase, and catalases. These enzymes directly eliminate the harmful AOS. By enhancing the levels of these proteins in transgenic plants via transformation technology the improvement of tolerance against oxidative stress is being attempted. In our research, we are generating transgenic maize lines that overproduce various antioxidative stress enzymes and we are assessing the performance of these plants during chilling stress.