Developing salt-tolerant crop plants: challenges and opportunities.

Soil salinity, one of the major abiotic stresses reducing agricultural productivity, affects large terrestrial areas of the world; the need to produce salt-tolerant crops is evident. Two main approaches are being used to improve salt tolerance: (i) the exploitation of natural genetic variations, either through direct selection in stressful environments or through mapping quantitative trait loci and subsequent marker-assisted selection; and (ii) the generation of transgenic plants to introduce novel genes or to alter expression levels of the existing genes to affect the degree of salt stress tolerance. Here, we discuss the challenges and opportunities provided by recently developed functional tools for the development of salt-tolerant crops.