Ex-foliar application of glycine betaine and its impact on protein, carbohydrates and induction of ROS scavenging system during drought stress in flax (Linum usitatissimum)

Abstract

Crop plants have an innate capacity to acclimatize and survive myriad stresses in field conditions. This acclimatization to stress enhances crop stand in field and productivity of plant. Inter alia field crops withstand drought stress (hydropenia) by inducing synthesis or accumulation of osmolytes such as (i) proline and other amino acids, (ii) glycine betaine (GB), (iii) soluble carbohydrates, and (iv) reactive oxygen species (ROS) scavenging system as intrinsic drought antagonizing molecules. Precise in vivo induction of osmolytes and their effect on ROS scavenging system in flax/linseed has not been elucidated. The investigation was carried out to identify a tolerant and susceptible cultivar of flax from a core collection of 53 core accessions and evaluate the role of compatible osmolytes in Linum usitatissimum under hydropenia. We screened eight morphometrically diverse flax genotypes in field under irrigated and un-irrigated condition and classified them as tolerant and susceptible genotypes. Further, we examined the effect of ex-foliar glycine betaine application - a signature molecule involved in drought tolerance, on selected tolerant and susceptible varieties. Our results showed stimulatory impact of glycine betaine on accumulation of ROS scavenging antioxidants, total soluble protein and on its own accumulation. While the ex-foliar application had no inhibitory effect on the growth of plants; accumulation of free proline, amino acids and carbohydrates are inhibited par se in flax. Our findings reveal, flax is a non-accumulator of glycine betaine and exogenous application of glycine betaine enhances its own levels during drought stress.

Keywords: Antioxidants; Drought/hydropenia; Flax; Glycine betaine; Reactive oxygen species.