Fig.1

Responses mechanism towards abiotic stress tolerance. Primary stresses such as drought, salinity, cold, heat and chemical pollution, cause cellular level injury and secondary stresses like osmotic and oxidative stress. The initial stress signals that is osmotic and ionic effects or changes in temperature or membrane fluidity activates the signaling process and transcription panels, which activate stress- mechanisms to restore homeostasis and to defend and repair damaged proteins and membranes. Inadequate responses at one or more steps in the signaling and gene activation process might ultimately result in irreversible changes in cellular homeostasis and in the destruction of functional and structural proteins and membranes, leading to cell death. Reprinted from Vinocur and Altman (2005) with permission of © (2005) Elsevier. ABF ABRE binding factor, AtHK1 Arabidopsis thaliana histidine kinase-1, bZIP basic leucine zipper transcription factor, CBF/DREB C-repeat-binding factor/ dehydration-responsive binding protein, CDPK calcium-dependent protein kinase, COR cold-responsive protein, Hsp heat shock protein, LEA late embryogenesis abundant, MAP mitogen-activated protein, PLD phospholipase D, PtdOH, phosphatidic acid, PX peroxidase, ROS reactive oxygen species, SOD superoxide dismutase, SP1 stable protein 1