Abstract Detail

Population Genetics/Genomics

Daundasekara, Kasuni [1], Garza, Elyssa [1], Pepper, Alan [2].

The evolutionary-genomic history of genes underlying serpentine tolerance in Caulanthus amplexicaulis var barbarae.

Adaptation to extreme environments is an important problem in ecology and evolutionary biology. Serpentine soil, which has high concentrations of toxic heavy metals (Ni, Cr, and Co) and low concentrations of essential plant nutrients (N, P, S, and K), is an excellent model environment to study plant adaptations to extreme environments. The tribe Thelypodieae (Brassicaceae) contains several taxa that are endemic to serpentine. Among these are the annual mustard, Caulanthus amplexicaulis var barbarae (CAB), which is serpentine tolerant, and its sister taxon, Caulanthus amplexicaulis var amplexicaulis (CAA), which is serpentine intolerant. This two-plant system is a superb model to study genetic and molecular mechanisms underlying serpentine tolerance. Several approaches (QTL analysis, coding sequence evolution, RNAseq) are being used in our laboratory to identify candidate genes for serpentine tolerance in CAB. In this study, we are using the gene ancestry of CAB and CAA as an additional tool to prioritize candidate genes. To trace the ancestry of CAB and CAA, we are using ~30 species within the genera Caulanthus, Streptanthus, and a few other related genera. Elucidation of the phylogenetic history of CAB and CAA is challenging due to at least one known episode of recent introgression. Here, we are determining the evolutionary history of CAB and CAA by building highly resolved gene phylogenies from both organellar and nuclear genomes. Results from chloroplast and mitochondrial phylogenies show that the maternal lineage of CAB and CAA clade is likely a serpentine intolerant Caulanthus lineage, while results from a nuclear phylogeny inferred using SNPs in putative single-copy nuclear genes provided evidence for the paternal lineage to be a Streptanthus lineage. We will be using gene-tree discordance between organellar and nuclear phylogenies to identify nuclear loci with paternal inheritance and explore the potential of using this knowledge together with data from QTL analysis, coding sequence evolution, and RNAseq to prioritize candidate serpentine tolerance genes for further investigation.

1 - Texas A&M University, Biology, 400 Bizzell St, College Station, Texas, 77843, United States
2 - Texas A&M University, Department Of Biology, Texas A&M University, TAMU 3258, 214 Bsbe, College Station, TX, 77843, United States

Keywords:
Brassicaceae
serpentine
hybridization
phylogeny
candidate genes.

Presentation Type: Poster
Session: P3, Population Genetics/Genomics Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3PG001
Abstract ID:163
Candidate for Awards:None