Identifying the guard cell ion channels responsible for drought tolerance in rice

Abstract

newline One-half of the world s population consumes rice and wheat as a major portion of their diet. It is well known that of all the cereals, rice tops the list as the leading staple food. In India, more than 65% of the population consumes rice as staple food. The modern rice production is may not enough to feed the growing population of India. Climate change is drastically affecting the cultivation of rice, and its output is affected significantly by newlinewater stress. An adaptation of a plant to water deficit conditions is orchestrated by efficient water uptake and a stringently-regulated water loss. Transpiration remains the principal means of water loss from plants and is mediated by microscopic pores called stomata. Stomatal aperture gating is facilitated by ion channels and Aquaporins (AQP) which regulate the turgidity of the guard-cells. In a similar manner, efficient water uptake by the roots is controlled by the presence of AQPs in the plasma membrane of root cells. newlineIn the present study, we compared the electrophysiological properties and trans-membrane water permeability coefficient measurements of guard cell protoplasts (GCP) from drought-tolerant and sensitive varieties of Oryza sativa L. The guard-cells isolated from the drought sensitive lowland rice variety ADT-39 show significant low osmotic water permeability than the drought-tolerant rice varieties of Anna (lowland) and DoddaByraNellu (upland wild). A detailed electrophysiological profiling of the guard cells from these varieties of rice was conducted. Reversal potential measurements to gauge selectivity, kinetics of channel gating and blocker studies were performed on these guard cell protoplasts, newline