Drought Responses of Leaf Tissues from Wheat Cultivars of Differing Drought Tolerance at the Metabolite Level

Abstract

Drought has serious effects on the physiology of cereal crops. At the cellular and specifically the metabolite level, many individual compounds are increased to provide osmoprotective functions, prevent the dissociation of enzymes, and to decrease the number of reactive oxygen species present in the cell. We have used a targeted GC-MS approach to identify compounds that differ in three different cultivars of bread wheat characterized by different levels of tolerance to drought under drought stress (Kukri, intolerant; Excalibur and RAC875, tolerant). Levels of amino acids, most notably proline, tryptophan, and the branched chain amino acids leucine, isoleucine, and valine were increased under drought stress in all cultivars. In the two tolerant cultivars, a small decrease in a large number of organic acids was also evident. Excalibur, a cultivar genotypically related to Kukri, showed a pattern of response that was more similar to Kukri under well-watered conditions. Under drought stress, Excalibur and RAC875 had a similar response; however, Excalibur did not have the same magnitude of response as RAC875. Here, the results are discussed in the context of previous work in physiological and proteomic analyses of these cultivars under drought stress.

Alginate oligosaccharides enhanced Triticum aestivum L. tolerance to drought stress

“…D1 protein, which is encoded by psbA gene, is an important structural and functional component in Photosystem (PS) II complexes [25]. It is reported that psbA gene transcription level decreases significantly in wheat seedling under drought stress [26].…”

Whole-Genome Mapping of Agronomic and Metabolic Traits to Identify Novel Quantitative Trait Loci in Bread Wheat Grown in a Water-Limited Environment

“…Drought stress, which has been identified as the most devastating abiotic constraint on crop productivity (Francia et al, 2005;Reynolds et al, 2005), causes substantial perturbations in plant metabolism (Bowne et al, 2011(Bowne et al, , 2012. Previous QTL studies of agronomic traits in wheat have lacked information on the biochemical pathways underlying those traits and their responses to drought.…”

“…Recent studies have shown that metabolic and proteomic profiles of cv Excalibur differ from those of cv Kukri following cyclic drought (Ford et al, 2011;Bowne et al, 2012). Thus, it should be possible to use progeny from a cv Excalibur/Kukri cross to map QTLs affecting the levels of individual metabolites under drought stress conditions.…”

Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants

“…Under drought, the quantity of proteins usually declines, while free amino acids tend to accumulate being partially converted into compatible solutes (e.g., proline) as reported by several groups during the past decades (Yoshiba et al, 1997;Su and Wu, 2004;Gruszka Vendruscolo et al, 2007;Parida et al, 2008;Bowne et al, 2012). Proline accumulation under abiotic stresses was reviewed in detail by Verbruggen and Hermans (2008).…”

“…Sink capacities may be strongly reduced under drought and heat. This may lead to an abnormal type of senescence accompanied by accumulation of free amino acids which could be partially converted into osmoprotectants in source leaves (Bowne et al, 2012). This process is initially reversible, but when prolonged it may turn into senescence finally leading to organ death.…”