An award has been made to Robert A. Andersen (Bigelow Laboratory for Ocean Sciences, West Boothbay Harbor, Maine), Rose Ann Cattolico and Gabrielle Rocap (University of Washington, Seattle, Washington), Robert Jansen, Elizabeth Ruck and Edward Theriot (University of Texas, Austin Texas), Matt Julius (St. Cloud State University, St. Cloud, Minnesota), Stefano Draisma (National Herbarium and Leiden University, Leiden, The Netherlands) and Hiroshi Kawai (Kobe University, Kobe, Japan) to determine the relationships among the heterokont classes by generating two large molecular data sets. Currently, 14 taxonomic classes of heterokont algae are recognized, and they include over 100,000 described species (as many as one million total species has been estimated by experts). Common members include brown seaweeds (e.g., kelp) and the diatoms. Remarkably, despite two centuries of light microscopic study, 50 years of electron microscopic study, and 20 years of molecular investigations, the phylogenetic relationships among the 14 classes remains unknown. DNA sequences of seven nuclear, mitochondrial, and chloroplast genes from 270 heterokont algal species and 30 nonalgal relatives will be obtained and, entire chloroplast genomes from 30 species will be sequenced. The genome sequences will provide important new data for understanding chloroplasts and their origin(s), especially since knowledge in this field is greatly biased toward land plants. Algae serve as the base of the food chain for all organisms that dwell in the ocean and account for approximately half of the global photosynthesis, and therefore they provide approximately 50% of the oxygen we breathe. Members of the heterokont algae vary in morphology from simple unicells to highly complex seaweeds. Brown algae are the principal elements of seaweed beds and these macroalgae have high economic values as food and biomass resources. A number of heterokont algae are harmful to marine life. For example, some algae produce toxins that when concentrated in shellfish kill humans, while other species of heterokonts are well-known fish killers. Conversely, other heterokonts serve as a human food source, they are used in industrial processes and they have found new recognition in the nanotechnology industry. The closest relatives to the heterokont algae are the pseudofungi, which include many plant pathogens, such as the fungus that caused the Irish potato famine, and various molds and mildews. Graduate and undergraduate students and postdoctoral fellows from diverse cultural and ethnic backgrounds will be supported and trained in a wide diversity of fields, including evolution, genomics, molecular biology, computational biology, and plant biology. The research will be integrated with K-12 educators, public museums and parks using already established programs at several of the participating institutions. A Deep Brown web site already has been established, and it will be greatly expanded as part of this project.
Intellectual Merit - The goal of our project was to better understand the evolution of diatoms, a kind of single-celled plant. Diatoms are the basis of the food chain in oceans, lakes and streams around the world, and make much of the oxygen we breathe. Their shells are made from silica, literally glass. They fall to the bottoms of lakes and oceans and make diatomaceous earth. Because of their fossil record and unique biological properties, diatoms are of interest to a wide variety of scientists who study subjects ranging from climate change, food webs, water pollution. Our work makes diatoms better tools for all of these uses and more. Nanotechnologists are interested in diatoms because of the intricate minute patterns they are able to make out of silica, at scales humans cannot yet approach. Our research helps to identify appropriate models for study of development of the diatom shell. We have discovered a diatom which, although it is related to advanced diatoms, has a very primitvely structured shell. We named it Astrosyne. Diatoms attach to ships, water intake pipes and the like, which results in a process called "biofouling". They attach by mucilaginous pads. Astrosyne's closest relatives form such pads, but Astrosyne does not. A student on project is studying which suites of genes turn on and off in the development of these diatoms. By comparing primitve and advanced morphology, and pad-forming versus non-pad-forming in closely related diatoms, we hope to find clues which may ultimately lead to a detailed understanding of the genetic pathways which control specific changes in diatom shape and pad formation. We stress that this is a long-term goal, but that this kind of comparative study is a necessary first step. Many of the genes involved in fatty acid synthesis are in the chloroplast and so understanding the diatom chloroplast genome has relevance to development of diatom strains for biofuel production. Our investigations on the diatom chloroplast genome are going to more than double the available examples of diatom chloroplast genomes. We have shown that diatoms have some unique and unusual aspects to their chloroplast genomes compared to close relatives. They have more pseudogenes, and more plasmid-like inclusions, resulting in larger genomes than their relatives. In short, there are millions of diatom species. Understanding diatoms has great potential benefit to human economy and understanding of global ecology. Understanding how they are related to one another may allow scientists and technologists to better select model systems to study to address specific problems of need. Our research provides the necessary framework to organize what we know about diatoms and hopefully make that knowledge more useful. Broader Impacts - We have or are training 6 Ph.D. students on this grant. These students are going on to study the genomes of chloroplasts and mitochondria of diatoms and other organisms, to study evolution of diatom fatty acid genes (relevant to biofuels production), and to study the evolution of diatoms which form harmful blooms in streams. We use this research as examples in a class taught by the Principal Investigator on protozoa and algae. Undergraduates taking this class are in fields ranging from pre-medicine to biofuels. Our research is connected to museum outreach activities at the University of Texas at Austin. We use examples from this research to show K-12 teachers how study of phylogenetic trees can be a tool to make predictions organisms, their distribution in time and space, and their properties (including properties that may be useful to humans). Diatoms have great potential for practical use. But we know very little about them. This research itself will not produce practical uses. But we work hard to be aware of the practical purposes to which people would like to apply diatoms, and so direct our research to learn basic things about diatoms that will ultimately aid technological application of diatoms.
