Proteomics-based dissection of stress-responsive pathways in plants

Abiotic stress has an ability to alter the levels of a number of proteins, which may be soluble or structural in nature or which may exist before and after folding in the plant cell. The most crucial function of plant cell is to respond to stress by developing defence mechanisms. This defence is brought about by alteration in the pattern of gene expression. This leads to modulation of certain metabolic and defensive pathways. Owing to gene expression altered under stress, qualitative and quantitative changes in proteins are obvious. These proteins might play a role in signal transduction, antioxidative defence, antifreezing, heat shock, metal binding, antipathogenesis or osmolyte synthesis. A significant part of the literature shows the quantitative and qualitative changes in proteins, mainly employing western analysis, enzymatic kinetics, fraction isolation, one-dimensional SDS-PAGE electrophoresis, etc. Fortunately, recent developments in sensitivity and accuracy for proteome analysis have provided new dimensions to assess the changes in protein types and their expression levels under stress. The novel aim of this review is to do a side-by-side comparison of the proteins that are induced or overexpressed under abiotic stress, examining those from biochemical literature and the ones observed, sequenced and identified using the advanced proteomics and bioinformatic techniques.