Abstract Detail


Daundasekara, Kasuni [1], Garza, Elyssa [2], Pepper, Alan [3].

Identifying serpentine adaptation genes by tracing evolutionary-genomic history of Streptanthus, Caulanthus, and their allied genera (Brassicaceae) .

Plant adaptation to extreme environments is an important question 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, Ca and K), is an excellent model environment to study plant adaptations to extreme environments. The tribe Thelypodieae (Brassicaceae) includes the genera Caulanthus and Streptanthus and 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 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 that the paternal lineage is a Streptanthus ancestor. We are using gene-tree discordance between organellar and nuclear phylogenies to identify nuclear loci with paternal inheritance and explore the potential of using this information, together with data from QTL analysis, coding sequence evolution, and RNAseq to prioritize candidate serpentine tolerance genes testing using synthetic biology and CRISPR/CAS9 mutagenesis approaches.

1 - Texas A&M University, Biology, 400 Bizzell St, College Station, TX, 77843, United States
2 - 401 Fall Cir, APT B, 401 Fall Cir, APT B, College Station, TX, 77840, United States
3 - Texas A&M University, Department Of Biology, Texas A&M University, TAMU 3258, 214 Bsbe, College Station, TX, 77843, United States

candidate genes.

Presentation Type: Poster
Number: PPL007
Abstract ID:498
Candidate for Awards:None

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