Transgenic Approaches for Abiotic Stress Tolerance in Crop Plants

Abstract

Abiotic stresses including drought, salinity and cold are a major challenge for sustainable food production as they may decrease the potential yields in crop plants by 70 %. Success in breeding for better adapted varieties to abiotic stresses depends upon intensive efforts using novel biotechnological approaches, including molecular biology, genetics, plant and cell physiology and breeding. Many abiotic stress-induced genes have been identified and some have been cloned. The use of current molecular biology tools to reveal the control mechanisms of abiotic-stress tolerance, and for engineering stress-tolerant crops is based on the expression of specific stress-related genes. Hence, plant genetic engineering and molecular-marker approaches allow development of abiotic stress-tolerant germplasm. Transgenic plants carrying genes for abiotic stress tolerance are being developed, mainly by using Agrobacterium and biolistic methods; transgenics carrying different genes relating to abiotic stress tolerance have been developed in crop plants like rice, wheat, maize, sugarcane, tobacco, Arabidopsis, groundnut, tomato and potato. This chapter focuses on recent progress in using transgenic technology for the improvement of abiotic-stress tolerance in plants. It includes discussion of metabolic engineering for biosynthesis and accumulation of compatible osmolytes (i.e. proline, glycine betaine, ectoine and polyols), reactive oxygen species formation under abiotic stress, ROS scavenging and detoxification in plant cells, single gene transgenic versus multiple genes and transcription factors and their roles in management of abiotic stresses.