Abiotic Stress Tolerance In Wheat Research Articles

Molecular modeling and in-silico characterization of TaPase, a stress-modulated acid phosphatase gene from wheat (Triticum aestivum)

Acid phosphatases have been reported to play an important role to increase orthophosphate (Pi) availability under abiotic stress conditions thus affecting growth of plants. Previously, we have reported cloning of an acid phosphatase gene ( TaPase ), its expression analysis and regulation by different abiotic stresses. The present study was designed to analyze in-silico characterization and molecular modeling of TaPase by various bioinformatic approaches like motif analysis, phylogenetic tree construction, secondary structure prediction and 3D structure analysis. Phylogenetic studies of cloned TaPase gene along with other reported phosphatases revealed the existence of three groups. The 3D structure of TaPase protein was predicted by Phyre 2 server. The modeled structure was refined by energy minimization and stereochemical qualities were validated by PROCHECK, VADAR, Verify3D and QMEAN servers, indicating the acceptability of predicted model. Ligand binding studies indicated the interaction of histidine residue with zinc metal. Analysis of cis -elements provides molecular evidence for the possible involvement of TaPase in the process of abiotic stress tolerance in wheat. Based upon these results, a possible physiological role of TaPase in wheat is discussed. Normal 0 false false false EN-US X-NONE X-NONE

QTL on wheat (Triticum aestivum L.) chromosomes 1B, 3D and 5A are associated with constitutive production of leaf cuticular wax and may contribute to lower leaf temperatures under heat stress

Cooler canopy temperatures and glaucousness have both been identified as adaptive traits for improving abiotic stress tolerance in wheat. The objective of this study was to determine if glaucousness resulting from the constitutive production of leaf cuticular waxes was associated with cooler leaf and spike temperatures under heat stress and to identify associated quantitative trait loci (QTL). A set of 121 recombinant inbred lines (RILs) derived by crossing the heat tolerant wheat cultivar ‘Halberd’ and heat susceptible wheat cultivar ‘Karl92’ was utilized for QTL mapping. Flag leaf cuticular wax was extracted and quantified using a colorimetric technique at 10 days after pollination prior to initiation of the heat stress. The parental cultivars and RIL population were then subjected to a heat treatment of 38 °C and temperature depression of both leaf and spike was measured. The parental cultivar Halberd had high flag leaf wax content, and cooler leaf and spike temperatures compared to Karl92, with the RIL population showing significant genetic variation for these traits. QTL identified for leaf and spike temperature depression and leaf waxes explained 8–12 % of the phenotypic variation. Stable QTL for leaf wax content were located on chromosomes 1B and 5A with the 5A QTL region showing localization with QTL for leaf and spike temperature depression, indicating a genetic link between these traits. The results suggest that common genetic loci may influence both of these adaptive traits and could be targeted to improve adaptation to high temperature stress.

Transcriptional activation of Cor/Lea genes and increase in abiotic stress tolerance through expression of a wheat DREB2 homolog in transgenic tobacco

Wdreb2, previously isolated as a DREB2 homolog, is expressed in wheat seedlings under abiotic stresses, such as cold, drought, and high salinity, and following treatment with exogenous ABA. In the present study, we generated transgenic tobacco plants expressing Wdreb2 to clarify roles of Wdreb2 in stress tolerance and the direct trans-activation of Cor/Lea genes by WDREB2. Wdreb2 expression significantly improved freezing and osmotic stress tolerance in tobacco plants. Several putative stress- and ABA-responsive cis-elements were found in the 5' upstream regions of four wheat Cor/Lea genes, Wdhn13, Wrab17, Wrab18, and Wrab19. The expression level of a gusA reporter gene under control of Cor/Lea promoter sequences was enhanced by cold, drought and ABA treatment in transgenic tobacco plants. Moreover, the gusA expression level was markedly enhanced by Wdreb2 expression under nonstressful conditions. These results clearly indicate that WDREB2 acts as a transcription factor and positively regulates Wdhn13, Wrab17, Wrab18, and Wrab19 in the development of multiple abiotic stress tolerance in wheat.