Title : Genetic Engineering of Multiple Stress Resistance in Apple Through Enhancement of Antioxidant Enzymes

Objectives: During exposure to both biotic and abiotic stress, molecular oxygen can undergo reactions that result in the formation of reactive oxygen intermediates (ROIs) including singlet oxygen and highly reactive oxygen compounds such as hydrogen peroxide. ROIs and hydrogen peroxide are highly destructive to lipids, nucleic acids, and proteins. Collectively, the injury resulting from these reactive oxygen compounds is referred to as oxidative stress. In relation to fruit crops, oxidative stress plays a role in freezing and low temperature injury, sunburn (sunscald), and physiological scald. These are all major problems for the fruit industry and can significantly reduce fruit quality. Andrews and Johnson (1997) reported that sunburn on apples is a result of the combined effects of elevated temperatures and high light intensity both of which result in the formation of ROIs.