Abiotic stresses like drought, cold, heat and high salinity are the most damaging factors to agricultural productivity worldwide. Functional genomics has played a key role in making plant breeding more efficient in development of crop varieties tolerant to biotic and abiotic stresses. Numerous genes and their products respond to these stresses at transcriptional and translational level. Although many drought responsive genes have been discovered, it is still of great importance to analyse drought-inducible genes and their expression in drought-tolerant crops. In addition to various molecular markers, Expressed Sequenced Tags (ESTs) are currently used as a fast and efficient method of profiling genes expressed in various tissues, cell types or developmental stages. The genes, thus, discovered will be utilized in their transfer to commercially important crops through marker assisted selection or transgenic breeding. This review discusses the techniques currently most in use in gene expression analysis, together with some important experimental design variables, such as the developmental stage of the plant, stress intensity and duration, and how different stresses may interact when performing assays.
cold, drought, marker, crops species, gene expression, expressed sequenced tags