Bulk Segregant Analysis of an Induced Floral Mutant Identifies a<i>MIXTA</i>-Like R2R3<i>MYB</i>Controlling Nectar Guide Formation in<i>Mimulus lewisii</i>

Abstract

The genetic and developmental basis of many ecologically important floral traits (e.g., carotenoid pigmentation, corolla tube structure, nectar volume, pistil and stamen length) remains poorly understood. Here we analyze a chemically induced floral mutant of Mimulus lewisii through bulk segregant analysis and transgenic experiments and identify a MIXTA-like R2R3 MYB gene that controls nectar guide formation in M. lewisii flowers, which involves epidermal cell development and carotenoid pigmentation.