The investigator has previously characterized the expression pattern and gene structure of alleles of the maize p1 (pericarp color1) gene. P1 is a myb type of transcription factor and controls the biosynthesis of red flavonoid pigments called phlobaphenes. Previous findings suggest that allelic expression at the p1 locus is a function of the gene structure and gene organization, which is further regulated by epigenetic mechanisms. The investigator has now characterized a dominant modifier called Ufo1 (Unstable factor for orange1). In the absence of Ufo1, plants of P1-wr (white pericarp & red cob glumes) allele produce ears with colorless kernel pericarp and red cobs and this phenotype is highly stable. In the presence of Ufo1, the P1-wr confers variably enhanced kernel pericarp, cob and plant pigmentation. Preliminary expression studies demonstrate that the gain of pigmentation is associated with increased steady state levels of p1 transcript that is correlated with decrease in DNA methylation of promoter and coding sequence of the P1-wr. Further experiments will investigate Ufo1 induced de-regulation of a well-programmed expression profile via transient DNA methylation changes of p1 alleles. Specifically, 1) using bisulfite sequencing methods, this project will identify specific type(s) and position(s) of DNA methylation modifications in the p1 sequence in the presence of Ufo1, 2) genes identified from the microarray analysis of Ufo1 versus ufo1 genotype RNA will be further tested for their expression and functionality and 3) to clone the Ufo1 gene, the research project will begin to develop plant populations to fine map the Ufo1 factor within the known crude position on the short arm of chromosome 10. In the longer run, this study will lead to the identification of molecular marks and mechanisms that may regulate stability of transgenes and natural alleles. Graduate students and undergraduates students will perform the majority of the research on this project. This project will provide training opportunities in epigenetics, as well as in functional genomics.
