Resilience of cereal crops to abiotic stress: A review
AbstractIn the last century, conventional selection and breeding program proved to be highly effective in improving crops against abiotic stresses. Therefore, breeding for abiotic stress tolerance in crop plants should be given high research priority as abiotic stresses are the main factor negatively affecting crop growth and productivity throughout the globe. Advancement in physiology, genetics and molecular biology, have greatly improved our understanding of plant responses to stresses. Many studies show that salt tolerance is tightly associated with the ability to maintain ion homeostasis under salinity. Na+ transporter SKC1 unloads Na+ from xylem; plasma membrane N+/H+ antiporter SOS1 excludes sodium out of cytosol, and tonoplast Na+/H+ antiporter NHX1 sequesters Na+ into the vacuole. Silicon deposition in exodermis and endodermis of rice root reduces sodium transport through the apoplastic pathway. A number of transcription factors regulate stress-inducible gene expression that leads to initiating stress responses and establishing plant stress tolerance. Over expression of some transcription factors, including DREB/CBF and NAC, enhances salt, drought, and cold tolerance in rice. A variant of one of ERF family genes, Sub1A-1, confers immersion tolerance to lowland rice. These findings and their exploitation will hold promise for engineering breeding to protect crop plants from certain abiotic stresses. Although, cereal crops are also quite sensitive to various abiotic stresses, hence in this short review, we will present recent progresses in adaptation of cereal crops to salinity, drought and cold tolerance are emphasized and the future potentials are highlighted.
Keywords: Cereal crops, abiotic stresses, food insecurity, molecular breeding, quantitative trait loci (QTLs), salinity, water stress.
African Journal of Biotechnology, Vol 13(29) 2908-2921