Research Genetic analysis of the liverwort Marchantia polymorpha reveals that R2R3MYB activation of flavonoid production in response to abiotic stress is an ancient character in land plants Nick W. Albert1 , Amali H. Thrimawithana2 , Tony K. McGhie1 , William A. Clayton1,3, Simon C. Deroles1 , Kathy E. Schwinn1 , John L. Bowman4 , Brian R. Jordan3 and Kevin M. Davies1 1The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North, New Zealand; 2The New Zealand Institute for Plant & Food Research Limited, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand; 3Faculty of Agriculture and Life Sciences, Lincoln University, Christchurch 7647, New Zealand; 4School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia Summary Author for correspondence: The flavonoid pathway is hypothesized to have evolved during land colonization by plants Kevin M. Davies c. 450 Myr ago for protection against abiotic stresses. In angiosperms, R2R3MYB transcription Tel: +64 6 3556123 factors are key for environmental regulation of flavonoid production. However, angiosperm Email:
[email protected] R2R3MYB gene families are larger than those of basal plants, and it is not known whether the Received: 29 October 2017 regulatory system is conserved across land plants. We examined whether R2R3MYBs regulate Accepted: 19 December 2017 the flavonoid pathway in liverworts, one of the earliest diverging land plant lineages. We characterized MpMyb14 from the liverwort Marchantia polymorpha using genetic New Phytologist (2018) 218: 554–566 mutagenesis, transgenic overexpression, gene promoter analysis, and transcriptomic and doi: 10.1111/nph.15002 chemical analysis. MpMyb14 is phylogenetically basal to characterized angiosperm R2R3MYB flavonoid regulators. Key words: CRISPR/Cas9, evolution, Mpmyb14 knockout lines lost all red pigmentation from the flavonoid riccionidin A, flavonoid, liverwort, MYB, stress.