An award is made to Sarah Mathews (Lead PI), Jianhua Li (Co-PI), Harvard University; Reed S. Beaman (PI), Nico Cellinese (Co-PI), Yale University; Christopher S. Campbell (PI), University of Maine; Richard C. Cronn (Collaborator), USDA Forest Service; Sean W. Graham (Co-PI), University of British Columbia; Stefanie M. Ickert-Bond (PI), University of Alaska; Dean G. Kelch (PI), University of California-Berkeley and California State Herbarium; Aaron I. Liston (PI), Oregon State University; Linda A. Raubeson (PI), Central Washington University; Gar W. Rothwell (PI), Gene Mapes (Co-PI), Ohio University; Andrea E. Schwarzbach (PI), University of Texas-Brownsville; Dennis W. Stevenson (PI), New York Botanical Garden; Ruth A. Stockey (Co-PI), University of Alberta to construct sequence-based phylogenetic hypotheses for all living gymnosperms and for seed plants overall, and morphology-based hypotheses to include ALL living species of gymnosperms (conifers, cycads, Gingko, and Gnetales) including examples from the fossil record, along with exemplar angiosperms (flowering plants). Nuclear, plastid and mitochondrial sequences will be utilized in the analysis along with the morphological characters to allow the rich record of fossil gymnosperms to be included. All of the data (molecular, morphological, voucher, etc.) will be submitted to standardized and accessible databases through an enhanced version of the web-based informatics tool TOLKIN (Tree Of Life Knowledge and Information Network, www.tolkin.org). The evolution of the seed marks one of the most important innovations in the history of land plants and led to greater mating control and to enhanced survival and dispersal capabilities. Seed bearing plants dominate the landscape; today, forests and grasslands are among our most important resources. Understanding the origin(s) of seeds is basic to understanding seed plant phylogeny. Obtaining the needed phylogenetic framework is not a trivial undertaking and the multi-faceted approach is designed to address the inherent complexity of the problem, incorporating approaches not considered by all projects (e.g., including all gymnosperms, serious attention to the fossil data). While phylogenetic inference will be the main focus of the project, data will bear significantly on the understanding of historic patterns of biotic change at the global level, and will provide insight into the origins of many important plant traits, including those that are the basis of breeding programs in horticulture and forestry. In addition to training students, workshops for K-12 teachers will be held at several botanic gardens.
This project supported the analysis of chloroplast genomes to assess phylogenetic relationships within gymnosperms as well as documenting morphological variation in both extant and extinct members of gymnosperms by constructing a morphological matrix which includes approximately 70 fossil taxa and 200 living taxa, scored for 200-240 characters. Within gymnosperms (naked seed plants) we can recognize several groups such as the conifers (e.g., pines, spruce, junipers, podocarps), cycads, Ginkgo (maidenhair tree) and the Gnetales. In particular the current project as part of the larger Collaborative Research: Gymnosperms on the Tree of Life: Resolving the Phylogeny of Seed Plants project focused on the Gnetales. The Gnetales are an enigmatic assemblage of plants including Mormon-tea (Ephedra, Figs. 1-6), Gnetum and Welwitschia. Ephedra comprises 50 species distributed in Africa, Asia, North America, South America and Europe (Fig. 5). Ephedra has been resolved as the sister to a clade comprised of Gnetum and Welwitschia in most phylogenetic analyses. Welwitschia is a monotypic genus endemic to the Namib Desert (often referred to as "stranded octopuses"), while Gnetum is a tropical liana (seldom a tree) of SE Asia, Africa and South America. The Gnetales has featured prominently in one of plant sciences major unanswered challenges: the origin of seed plants. A better understanding of this enigmatic group and their biogeographic history is of pivotal importance to understanding seed plant evolution and will shed light on dispersal routes and ancestral areas. While extant gymnosperms appear monophyletic, the relative position of the Gnetales remain unresolved. Analysis of whole chloroplast genome data for Ephedra support the monophyly of Ephedra. The majority of species relationships are robustly supported by plastome data. New World clades are derived from within Old World clades. Divergence time estimation supports an Oligocene divergence of the Asian and New World clades and Miocene dispersal into South America well before the closure of the Isthmus of Panama. Furthermore, as compared to plastome data from pines, these result reflect a relatively recent divergence of extant Ephedra. In fact they support the hypothesis that extant diversity in Ephedra is the result of a second recent radiation in the Paleogene, rather than being of Cretaceous age as some of the recent fossils might suggest. Our detailed comparative analysis of seed coat surfaces in both extant and extinct fossil members of the genus Ephedra corroborates the hypothesis that Cretaceous ephedroid fossils are extinct stem relatives to the extant clade. Biogeographically, Ephedra supports a classic Beringian disjunction and its biogeographic history appears dominated by long-distance dispersal (Fig. 5). The Solexa sequencing presents a relatively inexpensive and efficient way to produce whole plastome data capable of resolving species relationships within Ephedra. Numerous rare to obtain samples of Chinese Ephedra were added to the DNA bank for Gnetales by the PI. We have published 4 articles (including 1 in review), presented 13 research presentation at national and international conferences (incl. 6 invited symposium presentation) resulting from this NSF support. In the course of this study one post-doctoral accociate, one graduate student, four female undergraduate students (incl. one female REU student) as well as a high school student (RAHSS = Research Assistantships for High School Students) were trained in molecular laboratory techniques and phylogenetic analysis and other bioinformatics tools. Support from the grant has allowed these students to graduate in a timely manner, or enter graduate or medical school. Finally, the PI participated in educational outreach to promote the use and understanding of gymnosperms in several venues both locally and on the national level. We made four educational kits available for sign out at the Museum of the North. These kits can be signed out by teachers to aid in science education using gymnosperms. Several teaching modules for comparing past and present biodiversity (particularly gymnosperm) using coal balls were developed during the grant and implemented in several biology courses. The PI will continue to use those teaching units for training undergraduate students and has them made available for use in the undergraduate science curriculum.
