Molecular and biochemical mechanisms associated with differential responses to drought tolerance in wheat (Triticum aestivum L.)

Drought stress is a common abiotic stress in wheat. In this study, PEG-induced drought stress caused significant decline in morpho-physiological characteristics in Bijoy but not in BG-25, suggesting that drought tolerance mechanisms exist in BG-25. Semi-quantitative RT-PCR (reverse transcriptase) revealed the upregulation of TaCRT1 (calreticulin Ca2+-binding protein) and DREB1A (dehydration responsive transcription factor) transcripts in drought-stressed roots of BG-25 and Bijoy, albeit to a lesser extent. These imply that increased TaCRT1 expression may be associated with the survival of the wheat plants under drought conditions. In addition, DREB1A suggests its involvement in gene regulation associated with drought tolerance. Higher antioxidant enzyme capacity (catalase, peroxidase and glutathione reductase) along with less MDA content in roots of BG-25 suggests that wheat tolerance to drought stress could be associated with higher oxidative scavenging ability. Finally, elevated S-metabolites (glutathione, methionine and cysteine) and proline in BG-25 indicates that strong antioxidant defense play a vital role in drought tolerance in wheat.