Proteomic exploration reveals a metabolic rerouting due to low oxygen during controlled germination of malting barley (Hordeum vulgare L.)

Clare E O'Lone; Angéla Juhász; Mitchell Nye-Wood; Hugh Dunn; David Moody; Jean-Philippe Ral; Michelle L Colgrave

doi:10.3389/fpls.2023.1305381

Proteomic exploration reveals a metabolic rerouting due to low oxygen during controlled germination of malting barley (Hordeum vulgare L.)

Front Plant Sci. 2023 Dec 11:14:1305381. doi: 10.3389/fpls.2023.1305381. eCollection 2023.

Authors

Clare E O'Lone^{1

2}, Angéla Juhász¹, Mitchell Nye-Wood¹, Hugh Dunn³, David Moody⁴, Jean-Philippe Ral², Michelle L Colgrave^{1

5}

Affiliations

¹ Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Edith Cowan University, School of Science, Joondalup, WA, Australia.
² Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, ACT, Canberra, ACT, Australia.
³ Pilot Malting Australia, Edith Cowan University, School of Science, Joondalup, WA, Australia.
⁴ Barley Breeding, InterGrain Pty Ltd, Bibra Lake, WA, Australia.
⁵ Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Brisbane, QLD, Australia.

Abstract

Barley (Hordeum vulgare L.) is used in malt production for brewing applications. Barley malting involves a process of controlled germination that modifies the grain by activating enzymes to solubilize starch and proteins for brewing. Initially, the grain is submerged in water to raise grain moisture, requiring large volumes of water. Achieving grain modification at reduced moisture levels can contribute to the sustainability of malting practices. This study combined proteomics, bioinformatics, and biochemical phenotypic analysis of two malting barley genotypes with observed differences in water uptake and modification efficiency. We sought to reveal the molecular mechanisms at play during controlled germination and explore the roles of protein groups at 24 h intervals across the first 72 h. Overall, 3,485 protein groups were identified with 793 significant differentially abundant (DAP) within and between genotypes, involved in various biological processes, including protein synthesis, carbohydrate metabolism, and hydrolysis. Functional integration into metabolic pathways, such as glycolysis, pyruvate, starch and sucrose metabolism, revealed a metabolic rerouting due to low oxygen enforced by submergence during controlled germination. This SWATH-MS study provides a comprehensive proteome reference, delivering new insights into the molecular mechanisms underlying the impacts of low oxygen during controlled germination. It is concluded that continued efficient modification of malting barley subjected to submergence is largely due to the capacity to reroute energy to maintain vital processes, particularly protein synthesis.

Keywords: barley; controlled germination; low-oxygen; malt; malting; mass spectrometry; plant breeding; proteomics.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The research is financially supported by an Industry Ph.D. Scholarship sponsored by Edith Cowan University (ECU), InterGrain Pty Ltd, and the Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture and Food (G1004654) (C.E.O.). The research was supported by the Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science (CE200100012) (M.N. and A.J.). The authors declare that this study received funding from InterGrain Pty. Ltd. The funder had the following involvement in the study: provided malting barley samples.