Among different organic solutes, glycine betaine (GB) is an important compatible solute under stress condition. It performs different functions, and under stressed environment, its role becomes pivotal as an osmoÀ/stress-protectant. Choline and glycine are precursor molecules in GB biosynthetic pathway. Choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH) function as biosynthetic enzymes. Under stress conditions, the role of increased GB contents has been advocated in stress tolerance through their involvement in different stress-responsive pathways. In an extreme halophyte Salicornia species, GB contents and BADH mRNA transcript increased under salinity stress. The role of exogenously supplied GB has also been shown in salt tolerance in plants. This offered opportunity for genetic engineering with genes involved in GB