eChapter Name: Identification of Salt Tolerant Crop Variety by Glycine Betaine (GB) Method
9789389571905
eBook Name: MOLECULAR DIAGNOSTICS A PRACTICAL MANUAL
by Diwakar Singh, K.P. Suthar, Reetu Mehta
Objective: To identify salt tolerant genotypes by Glycine Betaine (GB) method in laboratory.
Background information:
Salt or salinity is a biggest danger that causes reduction in crop productivity worldwide. Salinity reduces the germination percentage, plant vigour and ultimately loss in final crop yield. There are different physiological parameters that are affected by high level of salinity viz., oxidative stress, physical alteration of bio-membrane, nutritional imbalance, loss of cell division & cell expansion, water stress, genotoxicity and ion toxicity. Together, these effects reduce plant growth, development and survival. During the onset and development of salt stress within a plant, all the major processes such as photosynthesis, protein synthesis and energy and lipid metabolism are affected. During initial exposure to salinity, plants experience water stress, which in turn reduces leaf expansion (Petronia, et al. 2011).
The water-soluble compounds which, are low in molecular weight, accumulate at certain concentration known as “compatible solutes” or “osmolytes” is the common strategy adopted by many organisms to combat the abiotic stresses. Some common compatible solutes are betaines, sugars (mannitol, sorbitol and trehalose), polyols, polyamines and amino acid (proline). Their accumulation is favored under water-deficit or salt stress as they provide stress tolerance to cell without interfering cellular machinery. The tolerant or sensitive species show difference in the stress tolerance level based on levels of accumulation of these compounds during abiotic stress condition. Accumulation of osmolytes like glycinebetaine (GB) in cells is known to protect organisms against abiotic stresses via osmoregulation or osmoprotection. Other roles of GB like cellular macromolecule protection and ROS detoxification have been suggested as mechanisms responsible for abiotic stress tolerance. In addition, GB also influences expression of several endogenous genes in plants.