Regulation of the OsNHX1 Gene Expression: Identification and Characterization of Novel Transcription Factors

For half of the world´s population, rice is life. This cereal crop is considered an important staple food worldwide, and more than three billion people count on it for 50-80% of their daily calorie intake. Soil salinity is a major environmental constraint to crop production, resulting in considerable yield losses around the globe every year. According to the Food and Agriculture Organization (FAO), in 2008 over 6% of world's total land and over 20% of irrigated land were affected by high levels of salt. Irrigated land is only 15% of cultivated land, but it produces one third of the world’s food, raising awareness about salinity as a serious problem for crop productivity. Rice like as most crops is very sensitive to salt, showing salt stress symptoms and reduced yield at relatively low soil salinity levels (≈ 40 mM NaCl). Among the agronomically important cereals, rice shows the highest sensitivity to salt. However, some degree of genotype tolerance for salt stress is available in rice germplasm. To cope with salt stress conditions, plants evolved several and diverse response mechanisms. One of these mechanisms is tissue tolerance, in which high salt concentration is found in leaves but is compartmentalized, especially in the vacuole, reducing the deleterious effect of Na+ in the cytosol and driving water uptake to cells. Cation/H+ antiporters mediate the transport of Na+ into the vacuole.(...)