Osmoprotectants: potential for crop improvement under adverse conditions

Abstract

Abiotic stresses such as drought, cold, heat, and salinity are major factors that limit plant growth and development and account for a major loss in crop productivity worldwide. Thus, engineering plants for tolerance towards such environmental menaces is the prime concern for crop improvement programs. Engineering osmoprotectants biosynthetic pathway is considered as one among many successful approaches taken for crop improvement under adverse conditions. Osmoprotectants or compatible solutes are thought to act by stabilizing membranes and proteins and maintaining osmotic potential in the cell during stresses. Although not all crop plants are able to synthesize these special molecules, many stress tolerant plants are shown to accumulate them under stress conditions. This group primarily includes proline, glycine betaines, ectoine, trehalose, and polyols. However, many attempts have been made at engineering plant system with genes from biosynthetic pathways of osmoprotectants; these transgenic plants have shown different tolerance levels, because of many metabolic limitations. Thus, a more elaborate and wholesome approach may be required to look past the current scenario. This chapter will encompass the potential role of osmoprotectants in plant stress adaptation and the possibilities for crop improvement.