Drought tolerance in Triticum aestivum L. genotypes associated with enhanced antioxidative protection and declined lipid peroxidation

Abstract

Drought is one of the major constraints in wheat production and causes a huge loss at grain-filling stage. In this study we highlighted the response of different wheat genotypes under drought stress at the grain-filling stage. Field experiments were conducted to evaluate 72 wheat (Triticum aestivum L.) genotypes under two water regimes: irrigated and drought condition. Four wheat genotypes, two each of drought tolerant (IC36761A, IC128335) and drought-susceptible category (IC335732 and IC138852) were selected on the basis of agronomic traits and drought susceptibility index (DSI), to understand their morphological, biochemical and molecular basis of drought stress tolerance. Among agronomic traits, productive tillers followed by biomass had high percent reduction under drought stress, thus drought stress had a great impact. Antioxidant activity (AO), total phenolic and proline content were found to be significantly higher in IC128335 genotype. Differential expression pattern of transcription factors of ten genes revealed that transcription factor qTaWRKY2 followed by qTaDREB, qTaEXPB23 and qTaAPEX might be utilized for developing wheat varieties resistant to drought stress. Understanding the role of TFs would be helpful to decipher the molecular mechanism involved in drought stress. Identified genotypes (IC128335 and IC36761A) may be useful as parental material for future breeding program to generate new drought-tolerant varieties.

Keywords: Antioxidant activity; DSI; Drought; SOD; Triticum aestivum; Wheat.

Fig. 1

Variation in biochemical parameters/enzymatic activities in the shoots of contrasting wheat genotypes: drought-sensitive (IC138852 and IC335732) and drought-tolerant (IC36761A and IC128335). a Lipid peroxidation, b antioxidant activity, c total phenolic content, d carotenoid content, e proline content, f total chlorophyll content, g SOD, h POX and i GR. Bars indicate standard error of mean

Fig. 2

Expression of transcription factors qTaDREB (a), qTaExpb23 (b), qTaHSP20 (c), qTaWRKY2 (d), qTaNAC2a (e), qTaMyb33 (f), qTaHSP-sti (g), qTaHSP90 (h), qTaHSP40 (i) and qTaAPX (j) in drought susceptible and tolerant wheat genotypes. The transcript level of these two genes was normalized to actin expression. Each bar represents the mean from three independent experiments with standard error of mean

Fig. 2

Expression of transcription factors qTaDREB (a), qTaExpb23 (b), qTaHSP20 (c), qTaWRKY2 (d), qTaNAC2a (e), qTaMyb33 (f), qTaHSP-sti (g), qTaHSP90 (h), qTaHSP40 (i) and qTaAPX (j) in drought susceptible and tolerant wheat genotypes. The transcript level of these two genes was normalized to actin expression. Each bar represents the mean from three independent experiments with standard error of mean

Fig. 3

Gene ontology (GO) classification. Green, blue and yellow bars represent the number of TFs involved in the biological, molecular and cellular processes

Fig. 4

Functional annotation; pie chart created using Blast2GO. Depicted different GO terms represented as: a biological process, b molecular function, and c cellular component, respectively