Investigating the role of a polymorphism in the sequence of MYB7 and the evolution of flower color in the Clarkia clade Rhodanthos

Abstract

Determining how genetic changes alter developmental processes to generate diversity of phenotypes is a major objective of evolutionary developmental biology. Color patterning in animals and plants are employed as model systems to address this issue. In this study, individuals from the genus Clarkia were studied to investigate the evolution of basal pigmentation and white cup morphology. Pigmentation is the result of anthocyanin production, and putative regulators of anthocyanin production in Arabidopsis are AtMYB90, AtMYB113, and AtMYB114. To investigate the evolution of diverse pigmentation in Clarkia, the MYB7 transcription factor was investigated based on its sequence homology to AtMYB90, AtMYB113, and AtMYB114 from BLAST. MYB7 is one of the many proteins in the MYB family, which is a functionally diverse set of proteins represented in all eukaryotes. To determine if MYB7 is involved in the regulation of development of a phenotypically diverse set of flower color in Clarkia, n=31 total samples of Clarkia were phenotyped. Sequence data was obtained from samples to determine SNPs that could be used to genotype the individuals utilizing PCR RFLP. Based on comparing the distribution of phenotypes and genotypes, it was found that phenotype was independent of MYB7 presence (Fisher's exact test: p = 0.7393). These findings show that MYB7 was not associated with flower pigmentation in Clarkia. The elucidation of MYB protein function will help determine the contributions of MYB proteins to the biology of plants in general.