Biology subjects

Buerkle, C. A.

Publications and source records attributed to Buerkle, C. A..

2 recordsLinked to original sources

bioRxiv2018

Admixture mapping in interspecific Populus hybrids identifies classes of genomic architectures for phytochemical, morphological and growth traits

The genomic architecture of functionally important traits is key to understanding the maintenance of reproductive barriers and trait differences when divergent populations or species hybridize. We conducted a Genome-Wide Association Study (GWAS) to study trait architecture in natural hybrids of two ecologically divergent Populus species. We genotyped 472 seedlings from a natural hybrid zone of Populus alba and P. tremula for genome-wide markers from reduced representation sequencing, phenotyped the plants in common gardens for 46 phytochemical (phenylpropanoid), morphological, and growth traits, and used a Bayesian polygenic model for mapping. We detected three classes of genomic architectures: (1) traits with finite, detectable associations of genetic loci with phenotypic variation in addition to highly polygenic heritability, (2) traits with indications for polygenic heritability only, (3) traits with no detectable heritability. For class (1), we identified genome regions with plausible candidate genes for phenylpropanoid biosynthesis or its regulation, including MYB transcription factors and glycosyl transferases. GWAS in natural, recombinant hybrids represents a promising step towards resolving the genomic architecture of phenotypic traits in long-lived species. This facilitates the fine-mapping and subsequent functional characterization of genes and networks causing differences in hybrid performance and fitness.

evolutionary biology↗

bioRxiv2018

Caterpillars on a phytochemical landscape

Modern metabolomic approaches that generate more comprehensive phytochemical profiles than were previously available are providing new opportunities for understanding plant-animal interactions. Specifically, we can characterize the phytochemical landscape by asking how a larger number of individual compounds affect herbivores and how compounds covary among plants. Here we use the recent colonization of alfalfa (Medicago sativa) by the Melissa blue butterfly (Lycaeides melissa) to quantify plant metabolites and the performance of caterpillars as affected by both individual compounds and suites of covarying phytochemicals. We find that survival, development time and adult weight are all associated with variation in nutrition and toxicity, including biomolecules associated with plant cell function as well as putative anti-herbivore action. The plant-insect interface is complex, with clusters of covarying compounds in many cases encompassing divergent effects on different aspects of caterpillar performance. Individual compounds with the strongest associations are largely specialized metabolites, including alkaloids, phenolic glycosides and saponins. The saponins are represented in our data by more than 25 individual compounds with beneficial and detrimental effects on L. melissa caterpillars, which highlights the value of metabolomic data as opposed to approaches that rely on total concentrations within broad defensive classes.

ecology↗