Abiotic stress in crops: Candidate genes, osmolytes, polyamines, and biotechnological intervention

Agricultural production and quality are adversely affected by various abiotic stresses including water deficit conditions (drought), salinity, extreme temperatures (heat, cold), light intensities beyond those saturating for photosynthesis, and radiation (UVB, C). This is exacerbated when such exposure occurs during seed germination and reproductive phases of development. Estimates of crop losses can amount to billions of US dollars worldwide. To prevent such losses, it is necessary to develop stress-tolerant crops. One approach is to identify resistant germplasm using breeding strategies assisted by molecular markers and transfer those attributes to sensitive varieties, but this approach is a timely process. Introduction of genes that can improve stress tolerance in crops against heat, drought, and salinity is relatively a more effective technology. In this regard, the scientific community is well placed since a number of critical genes, particularly transcription factors that regulate gene expression in response to environmental stresses, have been identified and the proof-of-the-concept validated. Translation of the technology into major crops (rice, wheat, sorghum, and maize) and vegetable/fruit crops is the need of the times.