Characterization of Monolignol Oxidoreductases from the Berberine Bridge Enzyme-like Protein Family in Arabidopsis thaliana

Reinmar Stefan Eggers, Alexandra Jammer, Karl Gruber, Peter Macheroux, Silvia Wallner

Research output: Contribution to conferencePoster


Flavoproteins catalyze a plethora of biological reactions throughout all kingdoms of life. Among the flavoprotein superfamily, the members of the berberine bridge enzyme-like (BBE-like) subfamily (pfam 08031) were found to be present in bacteria, fungi and plants [1]. The family name derives from the so-called “berberine bridge”, a characteristic C-C bond formed during the cyclisation reaction of (S)-reticuline to (S)-scoulerine catalyzed by the berberine bridge enzyme [2, 3].
Based on sequence similarities, BBE-like enzymes were identified to be present throughout the plant kingdom ranging from two in the moss Physcomitrella patens to 57 in western poplar (Populus trichocarpa). Arabidopsis thaliana, known as the plant biologists beloved pet, harbors 28 genes encoding BBE-like proteins (AtBBE-like). Results obtained from microarray expression analyses suggest the involvement of AtBBE-like proteins in various stress-induced plant responses as well as developmental processes. Despite the similarities in sequences and structures, the biological functions of the individual AtBBE-like genes appear to be highly diverse, very specific, and non-systemic. Following the protein distance tree presented by Daniel et al. [4], we focus on the AtBBE-like proteins of subgroup six.
In order to complement the biochemical characterization of AtBBE-like subgroup 6, of which two were found to oxidize monolignols to their corresponding aldehydes [4], we generated tissue-specific reporter lines and loss-of-function mutants. Expression patterns of reporter lines were characterized in seedlings and showed expression mainly to be located in roots for all of the 5 genes of subgroup 6. Additionally, AtBBE-like13 reporter lines showed altered expression in lateral roots when treated with indole-3-acetic acid (IAA). Phenotypic description of loss-of-function mutants, a detailed description of reporter lines and physiological experiments comparing mutant to wild type plants will widen our understanding of the AtBBE-like protein family.

[1] Daniel et al. (2017) Archives of Biochemistry and Biophysics 632: 88–103.
[2] Battersby et al. (1963) Proceedings of the Chemical Society: 268.
[3] Winkler et al. (2006) The Journal of Biological Chemistry 281: 21276–21285.
[4] Daniel et al. (2015) The Journal of Biological Chemistry 290: 18770–1878

Original languageEnglish
Publication statusPublished - 6 Feb 2020
Event23rd DocDac 2020 - TU Graz, Graz, Austria
Duration: 6 Feb 20206 Feb 2020


Conference23rd DocDac 2020


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