Overexpression of Multiple Genes to Generate Salt-Tolerant Cotton

Crop production is threatened by abiotic stresses throughout the world. Among those abiotic stresses, soil salinity, drought, and heat are the major stresses encountered in many places of the world including West Texas. To meet the increasing global demand for food and fiber, it is important to come up with novel technologies that are capable of improving crop production. Genetic engineering is a major approach that can generate plants capable of withstanding severe abiotic stresses, while improving the quality of the product. Cotton is considered as the main cash crop in West Texas. Soil salinity is a main abiotic stress that adversely impacts the growth, yield, and quality of cotton. Even though Na+ is a major cation present in soil solutions, high Na+ concentrations are toxic to plants due to the negative effects on plant metabolism and cellular processes. Over the years several genes have been introduced into transgenic plants to increase salt resistance, and these genes include AtNHX1 and SOS1. The gene AtNHX1 encodes a vacuolar membrane-bound sodium proton antiporter, whereas the gene SOS1 encodes a plasma membrane-bound sodium proton antiporter. We hypothesized that co-overexpression of these two genes would lead to a higher salt tolerance in transgenic plants than single gene overexpressing plants and we confirmed this hypothesis in Arabidopsis. We are now introducing the AtNHX1-SOS1 gene construct into cotton in order to make cotton significantly more salt tolerant.