Maize specialized metabolome networks reveal organ-preferential mixed glycosides

Sandrien Desmet; Yvan Saeys; Kevin Verstaen; Rebecca Dauwe; Hoon Kim; Claudiu Niculaes; Atsushi Fukushima; Geert Goeminne; Ruben Vanholme; John Ralph; Wout Boerjan; Kris Morreel

doi:10.1016/j.csbj.2021.01.004

Maize specialized metabolome networks reveal organ-preferential mixed glycosides

Comput Struct Biotechnol J. 2021 Jan 26:19:1127-1144. doi: 10.1016/j.csbj.2021.01.004. eCollection 2021.

Authors

Sandrien Desmet^{1

2}, Yvan Saeys^{3

4}, Kevin Verstaen⁴, Rebecca Dauwe⁵, Hoon Kim⁶, Claudiu Niculaes⁷, Atsushi Fukushima⁸, Geert Goeminne^{1

9}, Ruben Vanholme^{1

2}, John Ralph⁶, Wout Boerjan^{1

2}, Kris Morreel^{1

2}

Affiliations

¹ Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium.
² Center for Plant Systems Biology, VIB, B-9052 Gent, Belgium.
³ Department of Applied Mathematics, Computer Science and Statistics, Ghent University, B-9052 Gent, Belgium.
⁴ Data Mining and Modelling for Biomedicine, Center for Inflammation Research, VIB, B-9052 Gent, Belgium.
⁵ Unité de Recherche BIOPI EA3900, Université de Picardie Jules Verne, 80000 Amiens, France.
⁶ Department of Biochemistry and the U.S. Department of Energy Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin, Madison, WI 53726, United States.
⁷ Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany.
⁸ RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa 230-0045, Japan.
⁹ VIB Metabolomics Core Ghent, VIB, B-9052 Gent, Belgium.

Abstract

Despite the scientific and economic importance of maize, little is known about its specialized metabolism. Here, five maize organs were profiled using different reversed-phase liquid chromatography-mass spectrometry methods. The resulting spectral metadata, combined with candidate substrate-product pair (CSPP) networks, allowed the structural characterization of 427 of the 5,420 profiled compounds, including phenylpropanoids, flavonoids, benzoxazinoids, and auxin-related compounds, among others. Only 75 of the 427 compounds were already described in maize. Analysis of the CSPP networks showed that phenylpropanoids are present in all organs, whereas other metabolic classes are rather organ-enriched. Frequently occurring CSPP mass differences often corresponded with glycosyl- and acyltransferase reactions. The interplay of glycosylations and acylations yields a wide variety of mixed glycosides, bearing substructures corresponding to the different biochemical classes. For example, in the tassel, many phenylpropanoid and flavonoid-bearing glycosides also contain auxin-derived moieties. The characterized compounds and mass differences are an important step forward in metabolic pathway discovery and systems biology research. The spectral metadata of the 5,420 compounds is publicly available (DynLib spectral database, https://bioit3.irc.ugent.be/dynlib/).

Keywords: Mass spectrometry; Specialized metabolism; Spectral metadata analysis; Zea mays.