Abstract Detail

Phytochemical

Tobin, Trinity M. [1], McCarthy, Elizabeth [2].

Using droplet digital PCR to examine the role of homeolog expression bias in flower color evolution in Nicotiana allopolyploids of different ages.

Allopolyploidy results from whole genome duplication accompanied by interspecific hybridization and has played a prominent role in angiosperm evolution. The resulting merger of divergent genomes produces genomic shock that can cause genomic, cytogenetic, gene expression, epigenetic, and phenotypic changes in allopolyploid species. Allopolyploidy can also result in homeolog expression bias, where the expression levels of progenitor copies of the same gene (homeologs) are skewed toward one progenitor over the other. Here, we examine whether changes in the direction and magnitude of homeolog expression bias among allopolyploid accessions from the same origin are associated with the differences in flower color observed among those accessions. We investigate this question using Nicotiana (Solanaceae) allopolyploid species of different ages, Nicotiana tabacum (~0.6 million years old as well as first generation synthetic lines) and Nicotiana section Repandae (~4 million years old), which each exhibit variation in flower color. We use droplet digital polymerase chain reaction (ddPCR) to determine transcript accumulation of each homeolog of the genes of the flavonoid biosynthetic pathway, the branched pathway that produces various colorless (to humans) flavonols and colorful anthocyanins. Differences in the composition of these pigments underlie the variation in flower color among the Nicotiana species examined here. Synthesis of these homeolog expression bias analyses with our data of the floral anthocyanin and flavonol pigment composition of these species will allow us to determine whether changes in homeolog expression bias drive changes in flower color during evolution of allopolyploid species.

1 - SUNY Cortland, Department of Biological Sciences, P.O. Box 2000, Cortland, NY, 13045, US
2 - SUNY Cortland, Department Of Biological Sciences, P.O. Box 2000, Cortland, NY, 13045, United States

Keywords:
allopolyploidy
Anthocyanins
droplet digital PCR
Evolution
flavonols
homeolog expression bias
Nicotiana.

Presentation Type: Poster
Number: PPM001
Abstract ID:876
Candidate for Awards:None