Abstract Detail



Comparative Genomics/Transcriptomics

Drummond, Chloe Pak [1], Chamberlain, Ian [2], Renner, Tanya [3].

A case of the blues, reds, and purples: flavonoid biosynthesis and evolution in Vaccinium L.

Vaccinium membranaceum Douglas ex Torr., tall bilberry, grows in western North America and the Great Lakes Region, and is economically important and in increasingly high demand due to the flavonoid secondary metabolites in its berries. Leaves of V. membranaceum have also been used for their flavonoid content to relieve ailments. The expression of flavonoid (phenylpropanoid) pathway genes and the secondary metabolite profiles in berries of related Vaccinium change with light quality, sometimes due to latitudinal or elevational gradients. Because domestication is not yet realized for V. membranaceum and harvesting pressure on natural populations remains high, understanding the environmental regulation of flavonoids in V. membranaceum can help with management of natural populations and inform future optimal growing conditions. Before assessing environmental regulation of gene expression and metabolite profiles in leaves and berries, we tested the evolutionary and genomic context of V. membranaceum. To do this required a robust Vaccinium-wide phylogeny. We estimated this using SuperCRUNCH and generated Maximum Likelihood and coalescent-based phylogenies using single-copy orthologs mined from our own V. membranaceum RNA-Seq data and available Vaccinium RNA-Seq data. Vaccinium, in particular bilberries (Vaccinium sect. Myrtillus), are known for their high berry flavonoid content. We hypothesized that within the genus, phenylpropanoid pathway genes have diverse functions, enabling the biosynthesis of various individual compounds. If so, we would expect to see an expansion of gene families in this pathway in Vaccinium. In addition, we expected that gene family members involved later in the phenylpropanoid pathway are more divergent in Vaccinium compared to those involved earlier in the pathway, which might be highly conserved with other Ericales. To test this, we ran HMMER to identify members of known phenylpropanoid pathway gene families from available genomes across Ericales plus two outgroups. We compared gene copy number and compared rates of evolution between gene families involved earlier or later in the pathway. Finally, we hypothesized that more gene copies or isoforms (due to alternative splicing) are expressed in bilberry control leaves and berries compared to other Vaccinium, contributing to a greater diversity of flavonoid products. With the caveat that the data were collected from different studies, we tested this by comparing gene and isoform counts in control and same-stage leaves and berries from our V. membranaceum and available V. myrtillus RNA-Seq data to those from the same tissues in other Vaccinium.


1 - The Pennsylvania State University, Department of Entomology, 512 Agricultural Sciences & Industries Building, University Park, PA, 16802, USA
2 - The Pennsylvania State University, Department of Entomology, 520 Agricultural Sciences & Industries Building, University Park, PA, 16802, USA
3 - The Pennsylvania State University, Department Of Entomology, 514 Agricultural Sciences & Industries Building, University Park, PA, 16802, United States

Keywords:
Vaccinium L.
bilberry
Flavonoids
Comparative genomics
transcriptomics.

Presentation Type: Oral Paper
Number:
Abstract ID:898
Candidate for Awards:Margaret Menzel Award


Copyright © 2000-2021, Botanical Society of America. All rights reserved

aws4