Executive Summary : | Drought and salinity are the two major abiotic stresses known to adversely affect plant growth and productivity worldwide. Plants exposed to an excess salt or water deficiency experience ionic and osmotic stress causing oxidative stress and finally resulting in cellular damage. Stomatal closure leading to a drastic decline in photosynthesis and inhibition of cell expansion is a common feature observed in plants experiencing drought or salinity stress. Further, prolonged exposure to stress or higher intensity of stress leads to decrease in metabolic processes, increased oxidative damage, and ultimately cause cell death. Stress tolerance is a complex mechanism with a plethora of biochemical pathways and complex regulatory mechanisms involved in regulating the water uptake, maintaining optimum carbon fixation rates, and maintaining ionic and redox homeostasis. While Arabidopsis thaliana is considered an excellent model to understand the fundamental physiological, biochemical, and molecular processes during development in plants, due to its glycophytic nature, the mechanisms of salt/drought stress tolerance cannot be explored in depth. In this scenario, Eutrema salsugineum, an extremophilic plant and a close relative of A. thaliana which is adapted to grow well under extreme conditions of salinity, drought, cold, and nitrogen starvation can be used as a model to elucidate the mechanisms of drought and salt stress tolerance. The current research proposal aims to analyze the physiological, biochemical (glycomics) and molecular basis of protection of photosynthesis and cell wall remodeling during drought, salt stress and subsequent recovery in E. salsugineum plants. The changes in photosynthetic gas exchange, chlorophyll fluorescence parameters, thylakoid membrane protein complexes during drought, salt stress and subsequent recovery in stress sensitive A. thaliana and extremophilic E. salsugineum plants will be compared. Further, the changes in PSI and PSII proteins will be assessed to understand their regulation in stress-sensitive and tolerant species. Since cell wall is an important component for maintaining the structural integrity of the cells during abiotic stress conditions, the structural characterization of cell walls of E. salsugineum and A. thaliana cells using glycomics approaches during salt, drought stress and upon recovery is proposed. This will address the mechanisms of cell wall remodeling employed by stress-tolerant E. salsugineum plants for protecting the cell wall from oxidative damage during salt or drought stress conditions and thus will shed light on the underlying mechanisms of stress tolerance and thus can be used for the identification of genetic determinants of stress tolerance. Elucidating these underlying mechanisms of stress tolerance in the proposed extremophilic plant will be pivotal for generating climate-resilient agricultural crop plants. |