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Contributed Talk

Session: : Interdisciplinary Tools to Advance Ecology 4

COS 108-3 - Association study of genetic variation and spectroscopic imaging variants

Tuesday, August 8, 2023
2:00 PM – 2:15 PM PDT
Location: D133-134

    Presenting Author(s)

  • CL

    Cheng Li

    Department of Geography, University of Zurich, Switzerland

    • Coauthor(s)

  • EC

    Ewa A. Czyz

    Department of Geography, University of Zurich, Switzerland

  • RR

    Rishav Ray

    Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Germany

  • RH

    Rayko Halitschke

    Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Germany

  • IB

    Ian T. Baldwin

    Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Germany

  • MS

    Michael E. Schaepman

    Department of Geography, University of Zurich, Switzerland

  • MS

    Meredith C. Schuman

    Department of Geography, Department of Chemistry, University of Zurich
    Zurich, Switzerland

Abstract: Plants are the trophic basis of terrestrial ecosystems and their diversity structures ecological communities. Genetic diversity is a key determinant of adaptive potential for species in a changing climate. Remote sensing of vegetation by its reflection of light is increasingly used to characterize trait distributions in plant communities. How leaves reflect light is determined by aspects of physiology and function emerging from the interaction of plant genomes with the environment. These include leaf structure, and contents of pigments, water, and other abundant constituents like lignins, phenolics, and proteins. High-resolution ("hyperspectral'') spectroscopy can characterize trait variation at finer scales, and may help to reveal underlying genetic variation: information important for assessing the potential of populations to adapt to global change.



In this study, we used a set of 360 inbred genotypes of the wild coyote tobacco Nicotiana attenuata: wild accessions, recombinant inbred lines (RILs), and transgenic lines (TLs) with targeted changes to gene expression, to dissect genetic versus non-genetic influences on variation in leaf spectra across three experiments. We calculated leaf reflectance from field spectroradiometer measurements covering visible to short-wave infrared wavelengths of light (400-2500 nm) using a standard light source and backgrounds, resulting in a small and quantifiable measurement uncertainty. Plants were grown in more controlled (glasshouse) or more natural (field) environments, and leaves were measured both on- and off-plant with the measurement set-up thus also in more to less controlled environmental conditions. Here, Entire spectra varied across genotypes and environments. We found that the greatest variance in leaf reflectance was explained by between-experiment and non-genetic between-sample differences, with subtler and more specific variation distinguishing groups of genotypes. The visible region was most variable, distinguishing experimental settings as well as groups of genotypes within experiments, whereas parts of the short-wave infrared may vary more specifically with genotype. Overall, more genetically variable plant populations had more varied leaf spectra. Based on these results, we then investigated associations between genetic variation and leaf spectral variation taking advantage of highly diverse genotypes of the MAGIC population and taking the identified experimental confounding factors into account. The preliminary results from genome-wide analysis identified around 30 SNPs associated with reflectance at certain wavelengths. The corresponding candidate genes with annotated functions indicated plausible underlying mechanisms.