Monocots (including such groups as grasses, palms, orchids, and philodendrons) include more than 65,000 species of flowering plants, occur in almost all habitats, and provide the great majority of the human diet. A definitive family tree for this group will be developed and used to understand the broad-scale evolution of monocots over geologic time. A total of 23 genes in 601 species, whole chloroplast genomes in 175 species, and all genes expressed in 50 species will be sequenced and used to reconstruct the evolutionary history of this group. Additionally, phenotypic data from living and fossil species will be collected, and all data will be analyzed integratively to provide a comprehensive understanding of monocot evolution.
The resulting family tree will provide the foundation for many new studies in physiology, ecology, biogeography, and genomics of flowering plants. Web access to all data and results will be provided to researchers and K-12 teachers and students. Several post-doctoral fellows, graduate students, and undergraduates (with a focus on women and minorities) will be trained, and four young faculty will be supported. A museum exhibit on the evolution of flowering plants will be produced for high-profile venues in New York, Chicago, Denver, and Berkeley, and a children's monocot garden exhibit will be developed at the New York Botanical Garden. Posters illustrating monocot diversity and evolution will be distributed to colleges, and staff will give talks at public high schools.
Monocots, comprising ca. 25% of all flowering plants, dominate many habitats and include many species with tremendous ecological and economic importance. Cereal grains (e.g. corn, wheat and rice) and many other edible taxa (e.g., bananas, taro, palms, yams, coconuts, asparagus and onions) are economically essential as primary sources of carbohydrates and oils; pasture grasses indirectly provide most meat protein. Numerous species have unexplored pharmaceutical properties (e.g., Agave, Costus, Dioscorea, Smilax) and several are noxious agricultural weeds (e.g., many grasses, Hydrilla, Eichhornia). Monocots also support a lucrative horticultural industry (e.g., bulbs, orchids, turf and ornamental grasses). From a biological perspective, monocots exhibit kaleidoscopic variation in anatomy, morphology, physiology, ecology, and geographic distribution. The Monocot Tree of Life Project has resolved longstanding uncertainties about relationships among distinct monocot lineages and greatly advanced understanding the molecular, developmental, and ecological innovations that have spurred monocot diversification. While much previous and ongoing genomic research had been performed on grains species in the grass family, the Monocot Tree of Life Project greatly expanded genomic resources for a diverse collection of monocot species. These data have greatly improved understanding of relationships among important monocot lineages (including grasses, sedges, bromeliads, bananas, palms, orchids, irises, agaves, onions, amaryllids, tulips, lilies, yams, and aroids). Moreover, the Monocot Tree of Life Project has advanced knowledge about the timing and impact of gene and genome duplication events over 130 million years of monocot history. For example, we resolved the timing of genome duplications that were fist identified in analyses of the rice and sorghum genomes. Our findings have implicated genome duplications as the source of raw genetic material for innovations in growth forms and reproductive structures. Further, these innovations have contributed to increased speciation rates in the grasses and orchids. At the same increased diversification rates in other monocot groups including palms and lilies are not associated with genome duplication events. Mapping of ecological traits - including mode of reproduction, growth form, mode of carbon fixation (photosynthesis) and habitat characteristics – onto the monocot tree of life is implicating drivers of diversification. For example, the origin of wind pollination within the Poales is significantly correlated with shifts to open habitats and small, inconspicuous, unisexual, and nectar-free flowers. Multiple origins of C4 photosynthesis within the grass family may be associated with a genome duplication event in the last common ancestor of the grasses. Origins of Crassulacean acid metabolism (CAM) aided photosynthesis in arid habitats are more broadly distributed across the monocot tree of life and we are continuing to assess whether gene and genome duplication events may be facilitating shifts to CAM from more typical C3 photosynthesis. Understanding the molecular basis for these transitions will aid development of biofuel, feed and food crops that are able to achieve high productivity in water-limited environments. More generally, the Monocot Tree of Life Project has developed a historical context that is illuminating 130 million years of monocot evolution. In addition, the genomics data we have generated is being used by a wide array of researchers performing comparative analyses of gene and genome structure and function. By understanding the timing of gene and genome duplications in relationship to developmental and ecological innovations, and changes in speciation rates, we are better able to predict the fate of species in changing local, regional and global environments. Further, we are informing current plant breeding and genetic engineering efforts by elucidating how plants have adapted to past environmental changes. The Monocots Tree of Life Project has been a very productive research program. We hope are work illustrates how genome data can be used to resolve species relationships and how knowledge species relationships can be used to understand the molecular, genetic, developmental and ecological processes that spawn biological innovation and diversification.
