Elliot Gardner PhD Candidate

Major adviser: Nyree Zerega, PhD

Research: Plant evolution and domestication

Research Interests:  Artocarpus; Moraceae systematics; underutilized crops; phylogenomics; pollination biology; plant domestication

Current Research

Dissertation: Evolutionary transitions: phylogenomics and pollination of Artocarpus (Moraceae)Artocarpus anisophyllus
(Moraceae) is a genus of about 70 tree species native to tropical Asia and Oceania. The genus also contains over a dozen nutritious underutilized food crops that could play a key role in tropical food security, including jackfruit, cempedak, terap, and breadfruit—a low-input, nutritious, perennial crop with yields that often surpass major annual, high energy-input staples like wheat and rice. Artocarpus evolved from wind pollinated ancestors but contains both wind and insect pollinated species, making it an ideal system for studying the shift from wind to insect pollination.

The primary question underlying my dissertation is this: what are the evolutionary implications of a shift from wind to animal pollination, and might such a shift be an important driver of diversification in flowering plants? My research combines phylogenetics, field experiments, and trait analyses to illuminate the evolutionary implications of pollination shifts while simultaneously generating resources to promote improvement of underutilized crops.

Phylogenomics of Artocarpus
I am using target-enrichment sequencing (HybSeq) of 458 genes to reconstruct the phylogeny of Artocarpus. The targets were developed from a draft genome assembly of Artocarpus camansi, the wild progenitor of breadfruit.

Artocarpus odoratissimusPollination biology of Artocarpus
Artocarpus pollination ranges from wind to a unique tripartite mutualism mediated by a parasitic fungus; however, the pollination mechanism for most species remains unknown. Field studies in Sabah, Malaysia, Hawai’i, and Florida aim to characterize pollination mechanisms for targeted species. Combined with larger-scale studies of morphology and floral scent, these studies will allow traits to be correlated with pollination mechanisms. Analyzed in a phylogenetic context, these data will help identify transitions from wind to animal pollination and associated evolutionary patterns.

Origins and diversity of terap (Artocarpus odoratissimus): the intersection of population genetics and phylogenetics
Terap (Artocarpus odoratissimus) is a prized tree crop in Borneo, where it is endemic, but is little known outside Southeast Asia. A morphologically distinct wild from exists, but its relationship to cultivated terap is unclear. I am using DNA microsatellite markers combined with phylogenomics (HybSeq) to test whether cultivated terap derives from the wild form and characterize the genetic diversity of this crop.

Other Projects:
Phylogeny and biogeography of Maclura (Moraceae)
Phylogeography of breadfruit using phylogenomic markers (HybSeq)
Conservation of the limestone endemic Artocarpus annulatus
Fungal communities of Artocarpus inflorescences

Williams, E.W., E.M. Gardner, R. Harris III, A. Chaveerach, J.T. Pereira, and N.J.C. Zerega. Out of Borneo: Biogeography, phylogeny, and divergence date estimates of Artocarpus (Moraceae). Accepted pending minor revisions. Annals of Botany.
Johnson, M.G., E.M. Gardner, Y. Liu, R. Medina, B. Goffinet, A.J., N.J.C. Zerega, and N.J. Wickett. 2016. HybPiper: Extracting coding sequence and introns for phylogenetics from high-throughput sequencing reads using target enrichment.Applications in Plant Sciences, 4(7), apps.1600016. http://doi.org/10.3732/apps.1600016
Gardner, E.M., M.G. Johnson, D. Ragone, N.J. Wickett, and N.J.C. Zerega. 2016. Low-coverage, whole-genome sequencing ofArtocarpus camansi (Moraceae) for phylogenetic marker development and gene discovery. Applications in Plant Sciences4(7), apps.1600017.http://doi.org/10.3732/apps.1600017
Gardner E.M., K.M. Laricchia, M. Murphy, D. Ragone, B.E. Scheffler, S. Simpson, E.W. Williams, N.J.C. Zerega. 2015. Primer Note: Chloroplast microsatellite markers for Artocarpus (Moraceae) developed from transcriptome sequences. Applications in Plant Sciences 3(9):1500049http://dx.doi.org/10.3732/apps.1500049.
Zerega, N.J.C., G. Ravikanth, E.M. Gardner, K. Laricchia, T. Melhem, M. Wang, C. E. Witherup, S. Setty, M.I. Zuberi, M.R. Jagdish, and D. Ragone. 2014. New genomic resources to understand genetic diversity and promote crop improvement of jackfruit (Artocarpus heterophyllus), breadfruit (A. altilis), and other under utilized Artocarpus crops. Procedings of the International Symposium on Jackfruit (Artocarpus heterophyllus) and Breadfruit (Artocarpus altilis Fosberg) of the Tropics.
Honors and Awards
2015 NSF Doctoral Dissertation Improvement Grant
2015 Mohamed bin Zayed Species Conservation Fund Grant
2015 Institute for Sustainability and Energy, Northwestern University, Student Research Grant
2015 Plant Biology and Conservation Graduate Student Research Grant, Northwestern University
2014 Botanical Society of America, Graduate Student Research Award
2014 Garden Club of America, Centennial Pollinator Fellowship
2014 Dr. John N. Nicholson Fellowship, Northwestern University
2014 Plant Biology and Conservation Graduate Student Research Grant, Northwestern University
2013 Systematics Research Fund, Research Grant
2013 American Society of Plant Taxonomists, Graduate Student Research Grant
2013 Torrey Botanical Society Student Training Fellowship