Floral Color, Anthocyanin Synthesis Gene Expression and Control in Cape Erica Species

N C Le Maitre; Michael David Pirie; Dirk U Bellstedt

doi:10.3389/fpls.2019.01565

Floral Color, Anthocyanin Synthesis Gene Expression and Control in Cape Erica Species

Front Plant Sci. 2019 Nov 28:10:1565. doi: 10.3389/fpls.2019.01565. eCollection 2019.

Authors

N C Le Maitre¹, Michael David Pirie^{2

3}, Dirk U Bellstedt¹

Affiliations

¹ Bellstedt Laboratory, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa.
² Johannes Gutenberg-Universität, Mainz, Mainz, Germany.
³ University Museum, University of Bergen, Bergen, Norway.

Abstract

Introduction: The Cape Floristic Region (CFR) is a biodiversity hotspot, recognized globally for its unusually high levels of endemism. The origins of this biodiversity are a long-standing topic of research. The largest "Cape clade," Erica, radiated dramatically in the CFR, its ca. 690 species arising within 10-15 Ma. Notable between- and within-species flower color variation in Erica may have contributed to the origins of species diversity through its impact on pollinator efficiency and specificity. Methods: We investigate the expression and function of the genes of the anthocyanin biosynthesis pathway that controls floral color in 12 Erica species groups using RT-qPCR and UPLC-MS/MS. Results: Shifts from ancestral pink- or red- to white- and/or yellow flowers were associated with independent losses of single pathway gene expression, abrogation of the entire pathway due to loss of the expression of a transcription factor or loss of function mutations in pathway genes. Discussion: Striking floral color shifts are prevalent amongst the numerous species of Cape Erica. These results show independent origins of a palette of mutations leading to such shifts, revealing the diverse genetic basis for potentially rapid evolution of a speciation-relevant trait.

Keywords: Erica; RT-qPCR; UPLC-MS/MS; anthocyanin; floral color; gene expression.