Elsevier

Food Chemistry

Volume 192, 1 February 2016, Pages 928-933
Food Chemistry

The effects of GA and ABA treatments on metabolite profile of germinating barley

https://doi.org/10.1016/j.foodchem.2015.07.090Get rights and content

Highlights

  • The change of metabolite during germination is time- and genotype dependent.

  • Sugars and amino acids are the most dramatically changed compounds.

  • Addition of GA enhanced the activities of starch-degrading enzymes.

  • Effect of GA and ABA on metabolite differs between barley genotypes.

Abstract

Sugar degradation during grain germination is important for malt quality. In malting industry, gibberellin (GA) is frequently used for improvement of malting quality. In this study, the changes of metabolite profiles and starch-degrading enzymes during grain germination, and as affected by GA and abscisic acid (ABA) were investigated using two wild barley accessions XZ72 and XZ95. Totally fifty-two metabolites with known structures were detected and the change of metabolite during germination was time- and genotype dependent. Sugars and amino acids were the most dramatically changed compounds. Addition of GA enhanced the activities of starch-degrading enzymes, and increased most metabolites, especially sugars and amino acids, whereas ABA had the opposite effect. The effect varied with the barley accessions. The current study is the first attempt in investigating the effect of hormones on metabolite profiles in germinating barley grain, being helpful for identifying the factors affecting barley germination or malt quality.

Introduction

Barley is a most widely used cereal crop for brewing industry, and malting is an essential step for the production of beer and wines. During malting, the enzymes related to starch degradation are developed or activated. Under the coordinative actions of these starch-degrading enzymes, including α-amylase, β-amylase, limit dextrinase (LD) and α-glucosidase, starch as well as other polysaccharides in the endosperm of the germinating grains is degraded into monosaccharide, mainly glucose for further fermentation (Manners, 1974). Therefore high activities of these hydrolytic enzymes are favorable for complete degradation of starch and polysaccharides, leading to high malt extract, an important quality trait for malt barley.

It is commonly known that addition of GA could promote germination of barley grains during malting (Himmelbach et al., 1998, Ritchie and Gilroy, 1998), which is attributed to enhanced synthesis and secretion of the enzymes related to seed germination (Bewley & Black, 1994). In the brewing industry, GA is frequently used for increasing activities of α-amylase and LD, thereby improving the malting quality (Chandler et al., 1984, Hader et al., 2003). On the other hand, ABA, as an antagonist of GA, inhibits seed germination (Frank, Scholz, Peter, & Engel, 2011). Chen and An (2006) used microarray analysis to investigate the transcriptional changes of barley aleurone in responses to GA and ABA treatments and detected more than 2200 genes, in which 1328 and 206 genes showed over threefold change under GA or ABA treatment. However, little effort has been done to study the impact of GA or ABA treatment on metabolites including sugars, amino acids or organic acids in geminating barley grains.

The measurement of small metabolites has been facilitated by the development of gas chromatography–mass spectrometry (GC–MS) technology. Hence the metabolite profile of a single sample can be obtained, which may allow us to make insight into the metabolic processes in response to germinating conditions, such as addition of GA and ABA (Fiehn, 2002, Goodacre et al., 2004). So far, GC–MS has been successfully applied in the studies on plant tolerance to abiotic stresses such as phosphate deficiency (Huang et al., 2008), salinity (Yousfi, Rabhi, Hessini, Abdelly, & Gharsalli, 2010) and drought (Guo et al., 2009). Frank et al. (2011) investigated the metabolites profiles of barley whole seeds during micro-malting, and Gorzolka, Lissel, Kessler, loch-ahring, and Niehaus (2012) conducted metabolomic analysis on barley malting at industrial scale.

In the modern barley breeding, narrower genetic diversity has become a bottleneck of developing the new cultivars with high biotic and abiotic stress tolerance, and better malt quality. Comparatively, wild barley is much wider in genetic diversity and regarded as an elite source of genes for crop improvement (Ellis et al., 2000). Recently, Tibetan wild barley is proved to be rich in genetic diversity of stress tolerance and barley quality. For instance, in comparison with cultivated barley, the wild barley shows greater variation in HvGlb1, encoding β-glucanase isoenzyme (Jin et al., 2011), β-amylase activity (BAA) and β-amylase thermostability (BAT) (Zhang et al., 2014). In the previous studies (Jin et al., 2011, Zhang et al., 2014), we found that XZ72 and XZ95 have higher activities of starch-degrading enzymes. So the two Tibetan wild barley accessions were used in this study.

In this study, a GC–MS-based strategy was used to investigate the impact of GA and ABA additions on metabolite profiles in the germinating seeds of the two Tibetan wild barley accessions during malting.

Section snippets

Malting procedure

Two Tibetan wild barley accessions, i.e. XZ72 and XZ95 were malted in Joe White Malting System (Adelaide, SA, Australia). The malting procedures were as below: (1) Steeping stage: 5–8–8–12–4–5–2 h (wet–dry–wet–dry–wet–dry–wet); (2) Germination stage: 96 h at 16 °C. GA (0.5 ppm) or ABA (0.5 ppm) was added at the last wet stage during steeping by adding them into individual containers. Seed samples were collected at 24 h, 48 h, 72 h and 96 h after germination, and freeze dried, and then grinded for

The changes of degrading enzymes activities and β-glucan content as affected by GA and ABA treatments during germination

The changes of degrading enzyme activities and β-glucan content in the germinating grains of the two barley accessions were determined every day during germination. The activities of the enzymes, including α-amylase, β-glucanase and LD showed the dramatic increase, while β-amylase activity remained little change. Meanwhile, β-glucan content declined greatly during germination (Fig. 1a–e).

GA treatment markedly increased the activities of α-amylase, β-glucanase and LD in both barley accessions,

Discussion

In the current study, XZ72 and XZ95 showed similar trend in starch degrading enzymes activities and β-glucan content as affected by GA and ABA treatments (Fig. 1), but the differences between two cultivars became predominant during germination. The metabolites of XZ72 and XZ95 had the similar content at the very beginning of germination, and differed between the two genotypes when the germination entered the second day (2 d). XZ72 had significantly higher metabolite level than XZ95 at the 4 d of

Conclusions

In this study, we used GC–MS to analyze changes of metabolites for two Tibetan wild barley accessions XZ72 and XZ95 during germination and as affected by addition of GA and ABA. α-amylase, β-glucanase and LD increased dramatically, and β-amylase activity remained little change during germination. Meanwhile, β-glucan content declined greatly. GA treatment caused great increase in the activities of some sugar-degrading enzymes, and ABA had the opposite effect. Sugars and amino acids are most

Acknowledgments

This research was supported by Natural Science Foundation of China (31129005 and 31330055), China Agriculture Research System (CARS-05) and Jiangsu Collaborative Innovation Center for Modern Crop Production (JCIC-MCP). We deeply thank Mr. Xianyin Zhang and Miss Mei Li, the technicians of 985-Institute of Agro-biology for providing convenience in the experiment.

References (34)

  • P.M. Chandler et al.

    The effects of gibberellins acid and abscisic acid on a-amylase mRNA levels in barley aleurone layers: Studies using an a-amylase cDNA clone

    Plant Molecular Biology

    (1984)
  • K. Chen et al.

    Transcriptional responses to Gibberellin and Abscisic acid in barley aleurone

    Journal of Integrative Plant Biology

    (2006)
  • R.P. Ellis et al.

    Wild barley: A source of genes for crop improvement in the 21st century?

    Journal of Experimental Botany

    (2000)
  • T.M. Enari et al.

    Centenary review: Mobilization of endosperm reserves during the germination of barley

    Journal of the Institute of Brewing

    (1986)
  • D.E. Evans et al.

    Improved prediction of malt fermentability by measurement of the diastatic power enzymes betaamylase, alpha-amylase, and limit dextrinase: II. Impact of barley genetics, growing environment, and gibberellin on levels of alpha-amylase and limit dextrinase in malt

    Journal of the American Society of Brewing Chemists

    (2009)
  • D.E. Evans et al.

    Improved prediction of malt fermentability by measurement of the diastatic power enzymes β-amylase, α-amylase, and limit dextrinase: I. Survey of the levels of diastatic power enzymes in commercial malts

    Journal of the American Society of Brewing Chemists

    (2008)
  • O. Fiehn

    Metabolomics: The link between genotypes and phenotypes

    Plant Molecular Biology

    (2002)
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