Theoretical and Applied Genetics

, Volume 130, Issue 5, pp 1053–1063 | Cite as

Variation in barley (1 → 3, 1 → 4)-β-glucan endohydrolases reveals novel allozymes with increased thermostability

  • Juanita C. Lauer
  • Suong Cu
  • Rachel A. Burton
  • Jason K. Eglinton
Original Article


Key message

Novel barley (1 → 3, 1 → 4)-β-glucan endohydrolases with increased thermostability.


Rapid and reliable degradation of (1 → 3, 1 → 4)-β-glucan to produce low viscosity wort is an essential requirement for malting barley. The (1 → 3, 1 → 4)-β-glucan endohyrolases are responsible for the primary hydrolysis of cell wall β-glucan. The variation in β-glucanase genes HvGlb1 and HvGlb2 that encode EI and EII, respectively, were examined in elite and exotic germplasm. Six EI and 14 EII allozymes were identified, and significant variation was found in β-glucanase from Hordeum vulgare ssp. spontaneum (wild barley), the progenitor of modern cultivated barley. Allozymes were examined using prediction methods; the change in Gibbs free energy of the identified amino acid substitutions to predict changes in enzyme stability and homology modelling to examine the structure of the novel allozymes using the existing solved EII structure. Two EI and four EII allozymes in wild barley accessions were predicted to have improved barley β-glucanase thermostability. One novel EII candidate was identified in existing backcross lines with contrasting HvGlb2 alleles from wild barley and cv Flagship. The contrasting alleles in selected near isogenic lines were examined in β-glucanase thermostability analyses. The EII from wild barley exhibited a significant increase in β-glucanase thermostability conferred by the novel HvGlb2 allele. Increased β-glucanase thermostability is heritable and candidates identified in wild barley could improve malting and brewing quality in new varieties.


Wild Barley Backcross Line Endosperm Cell Wall Wild Barley Accession Tibetan Wild Barley 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This research received financial support from Australian farmers and the Federal Government through the Grains Research and Development Corporation (GRS10407), the Australian Research Council Centre of Excellence in Plant Cell Walls (CE110001007) and an Australian Postgraduate Award through the University of Adelaide.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflicts of interest.

Supplementary material

122_2017_2870_MOESM1_ESM.docx (19 kb)
Supplementary material 1 (DOCX 18 KB)
122_2017_2870_MOESM2_ESM.docx (17 kb)
Supplementary material 2 (DOCX 17 KB)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  1. 1.School of Agriculture, Food and WineThe University of AdelaideGlen OsmondAustralia
  2. 2.Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and WineThe University of AdelaideGlen OsmondAustralia

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