Progress 10/01/07 to 09/30/13
Outputs
Target Audience: Students and researchers in botany and biology Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Traing opportunities: Ph.D. students: Andrew Pais, Juliet Lindo Undergraduate stduents:Charlotte Rastas, Chanel Wilson,Ahmad Youself Abuahmad,Kim Shearer, International Ph.D. student: Zhecheng (Andres) Qi, Zhejiang University, China How have the results been disseminated to communities of interest? Published in journal articles, presentations at conferences and invited seminars, and communicated in courses. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
These goals have revised in 2011 and extended to address molecular mechanisms of inflorescence evolution in the group. The robust plastid DNA phylogeny obtained from this research was used to understand morphological and molecular evolution and biogeographic history via comparative analyses. Synthesis of the results of these analyses are in progress of preparation for publications. Transformation system in C. canadensis was established. test of function of key keys regulating inflorescence development were continued. The role of dogwood TFL1 and LFY homolog in regulating flowering time was confirmed. Results are in preparation for publication.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
2013. Xiang, QY(X), RG Franks, DY Xie, R Qu, and X Liu. The beginning of a long journey to uncovering the genetic myth of inflorescence divergence in dogwoods Building the tools and testing the initial puzzle pieces. 27th NC Plant Molecular Biology Retreat. September 13-15th, Asheville, NC.
2013. Liu*, J Zhang*, AY Abuahmad*, R Franks, D Xie, Q-Y (J) Xiang. Cornus TFL1-like genes extended vegetative growth and rescued indeterminate inflorescence in Arabidopsis. Botanical Society of America 2013 Conference. New Orleans, LA, July.
2013. Qi, Zhechen; Y Yu, R Whetten, R Ranney, R Miller, R Lewandowski, QY(J) Xiang. Phylogenomics of Fothergilla by GBS comparing data yields of experimental repeats and software and evaluating phylogenetic outcomes of taxon sampling and data type. Botanical Society of America 2013 Conference. New Orleans, LA, July. Botanical Society of America 2013 Conference. New Orleans, LA, July.
1. 2013. Xiang, Q-Y(J). Understanding plant biodiversity in eastern United States and eastern China via collaborative research and teaching with Zhejiang University. NCSU 3rd International Expo.
2013. Pais, A, YL Guo, A Weakly, and Q-Y(J) Xiang. Time and space of the early diversification of the Mock Orange genus Philadelphus (Hydrangeaceae) and its close affinity to Carpenteria inferred from molecular data and phylogenetic analyses. NCSU Graduate Student Research Symposium. Spring, 2013.
2013. Shearer, K, QY(J) Xiang, R Ranney. Evolution of Genome Size in the Dogwood Genus Cornus L. (Cornaceae). North Carolina Undergraduate Students Research Conference. Charlotte, NC, August. 2013.
2012. Rastas*, C., X Liu*, and Q-Y(J) Xiang. Sequencing and evolutionary analysis of SEPALlATA-1 gene in dogwood family. 21st North Carolina State University Undergraduate Research Spring Symposium.
5. 2012.Wilson*, C., X Liu*, and Q-Y(J) Xiang. Genetics of inflorescence evolution in Dogwoods (Cornus L.). 11th Annual North Carolina State University Summer Undergraduate Research Symposium.
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Results were disseminated via oral presentations at 2012 professional conferences [Botanical Society of America (BSA); American Society of Plant Taxonomist (ASPT); SouthEast Population, Ecology; and Evolutionary Genetics (SEPEEG)], seminars [Sun Yat-Sen (Zhongshan) University; Chenshan Botanical Garden, Shanghai; Institute of Botany, Chinese Academy of Sciences, Beijing; Duke University; National Evolutionary Synthesis Center (NESCent); and Fudan University], and journal publications. Three manuscripts were published, two manuscripts in review, two manuscripts in preparation (see below). 1. The molecular phylogenetic study of Philadelphus (Hydrangeaceae, Cornales) found that the genus Carpenteria is nested within Philadelphus. The phylogeny-based molecular dating and biogeographic analyses suggested that the group evolved and early diversified into three lineages in southwestern North America during the late Paleogene period. The occurrence of the genus in eastern North America, Europe, and Asia was the result of subsequent colonization and evolution of the core Philadelphus lineage. The phylogenetic pattern suggested that classification of the genus needs revision. A manuscript on the results was submitted for publication. 2. Meta-analyses of biogeographic origins of intercontinental disjunct endemic lineages using the biogeographic method developed from this project found most Asian plant endemic lineages evolved from ancestors in Asia while most North American endemics evolved from ancestors with wide distribution in both continents. A manuscript is in press. 3. Comparative investigation of bract development and B-class MADS-box gene expression based on the molecular phylogeny revealed independent origins of the petaloid, involucral bracts in two sister lineages of dogwoods as represented the flowering dogwood (Cornus florida) and the bunchberrie (little dogwood) (Cornus canadensis). A manuscript was published. 4. An agrobacterium-mediated genetic transformation system has been established for the little dogwood C. canadensis. This has allowed experiments of functional analyses of floral and inflorescence genes in dogwoods (e.g., characterizing the phenotypic effects of silencing and over expression of these genes) that are on going. The transformation protocol has been published. 5. Comparative gene expression analyses of LFY gene showed that the gene was expressed during inflorescence and floral development in all four major lineages of dogwoods that differ in inflorescence architecture and no significant difference of gene expression pattern was observed among the species studied. This suggested that LFY activities are likely required for flowering in dogwoods (as found in the model plants), but not responsible for the divergent morphology of inflorescences evolved in different species. - A manuscript was submitted for publication. 6. Genetic transformation experiments of TFL1 gene from dogwoods demonstrated effects of the gene in regulating flowering time in Arabidopsis. - unpublished PARTICIPANTS: Individuals worked on the project: Graduate and undergraduate students: Xiang Liu, Jian Zhang, Ashley Brooks, Andrew Pais, Yuelong Guo, Juan Liu, Yi Yu, Chanel Wilson, A. Yousef Abuahmad, Charlotte Rastas, Wendy Harris. Students and postdocs benefit for training and professional development: Graduate students: Chunmiao Feng, Ashley Brooks, Wendy Harris, Yuelong Guo. Visiting graduate students and scientists: Yi Yu, Juan Liu, Zhecheng Qi, Yunpeng Zhao. Postdoctoral students: Jian Zhang. Under graduate students: Wade Robert, Chris Trlica, Charlotte Rastas, Chanel Wilson, A. Yousef Abuahmad. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: No further modification.
Impacts
The project finding from phylogenetic analyses advanced our understanding of the origin and evolution of this horticultural and medicinally important lineage (Cornales) that diverged early in the Asterids clade. The phylogenetic relationships among families and genera found in the study provide a basis for future improved classification and circumscription of the order and the families. The finding from biogeographic analyses supported the long-term debated view that eastern Asia is a center of origin and diversification for north Temperate plant evolution. The comparative analyses of inflorescence and floral development and genetics provided novel insights into the developmental mechanisms underlying the evolution of determinate umbel and head inflorescence types. The genetic transformation protocol established by the project was the first available for the dogwood order and may be applicable to other woody plant groups. This transformation system provides a platform for future functional genomic studies of the group. In summary, the studies addressed fundamental questions in evolutionary biology, contributing to better understanding of plant biodiversity and its conservation and evolution. Results of the genetic studies of inflorescence morphology have potential for horticulture and agriculture industry. The resources and molecular methods established for the project are useful to other biologists in biology, horticulture and medicinal sciences, and facilitated investigations of phylogeny and biogeography of other taxa, e.g., on Lilium and Smilax in the lab.
Publications
- Zhao, YP, WW Ma, QY Dai, ZC Qi, P Li. KM Cameron, J Lee, QY(J) Xiang, CX Fu. 2012. Comparative phylogeography of the Smilax hispida group (Smilacaceae) in eastern Asia and North America: Implications for allopatric speciation, causes of diversity disparity, and origins of temperate elements in Mexico. Molecular Phylogenetics and Evolution. In Review.
- Harris, WK, J Wen, and QY(J) Xiang. 2012. Inferring the Biogeographic Origins of Inter-Continental Disjunct Endemics using A Bayes-DIVA approach. Journal of Sysematics and Evolution. In press.
- Guo, YL, A. Pais, AS Weakley, QY(J) Xiang. 2012. Molecular Phylogenetic analysis suggests paraphyly and early diversification of Philadelphus (Hydrangeaceae) in western North America: New insights into affinity with Carpenteria. Journal of Systematics and Evolution. Submitted, in review.
- Liu, J, CM Feng, X Liu, CX Fu, RG Franks, and QY(J) Xiang. 2012. Expression of LFY homologs from dogwoods (Cornus L.): evaluating the role in inflorescence evolution. Annals of Botany. Special Issue on Inflorescence evolution. In Review.
- Harris, WK, SR Manchester, and QY(J) Xiang. 2012. Accounting for phylogenetic and optimization uncertainty and fossil distribution in biogoegraphic analysis of Cornales: A comparison between Bayes-DIVA (parsimony) and BayseLagragne (likelihood method). Systematic Biology. In preparation.
- Feng, CM, X Liu, Y Yu, DY Xie, RG Franks, and QY(J) Xiang. 2012. Evolution of bract development and B-class MADS box gene expression in petaloid bracts of Cornus s. l. (Cornaceae). New Phytologist. doi: 10.1111/j.1469-8137.2012.04255.x.
- Liu*, X, CM Feng*, R Franks, R Qu, DY Xie, and QY(J) Xiang. 2012. Plant regeneration and genetic transformation of C. canadensis: A non-model plant appropriate for investigation of flower development in Cornus (Cornaceae). Plant Cell Report. DOI 10.1007/s00299-012-1341-x.
- Liu*, J, ZC Qi, YP Zhao, CX Fu and Q-Y(J) Xiang. 2012. Chloroplast DNA phylogenomics of Monocots: Insights into the placement of Liliales and influences of gene partitions. Molecular Phylogenetics and Evolution. 64: 545-562.
- Xiang, QY(J), DT Thomas, and QP Xiang. 2011. Resolving and dating the phylogeny of Cornales: Effects of taxon sampling, data partitions, and fossil calibrations. Mol. Phylogen. Evol. 59: 123-138.
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: Results were disseminated via oral presentations at annual conference of Botanical Society of America, annual conference of American Society of Plant Taxonomist, seminars at Clemson University, International Botanical Conference, lectures for NCSU Systematic Botany course and Plant Biology Study Abroad course in China. A manuscript summarizing the findings of phylogenetic relationships and divergence times of the order Cornales was published in journal of "Molecular Phylogenetics and Evolution, 59: 123-138.". Manuscripts reporting results on biogeographic history of the order is in revision for publication, and manuscript reporting inflorescence development and evolution were published in New Phytologist. Manuscripts on evolutionary development of bracts of dogwoods are in preparation for publication. Manuscript reporting the new genetic transformation in dogwood is also inpreparation. PARTICIPANTS: Individuals worked on the project: Graduate students: Wendy Harris, Chunmiao Feng,Jian Zhang, Ashley Brooks, Juan Liu, Yi Yu, Chris Trlica, Wade Robert, Charlotte Rastas. Research specialist: Xiang Liu. Students and postdocs benefit for training and professional development: Graduate students: Wade Wall, Chunmiao Feng, Ashley Brooks, Wendy Harris, Yuelong Guo. Visiting graduate students: Yi Yu, Juan Liu Postdoctoral students: Norman Douglas, Jian Zhang. Under graduate students: Wade Robert, Chris Trlica, Charlotte Rastas. Collaborators: Stephen Manchester, University of Florida; Robert Franks, Department of Genetics, North Carolina State University; Deyu Xie, Department of Plant Biology,North Carolina State University. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: no further modification
Impacts
1. The phylogenetic analyses resulted in a well-supported phylogeny of Cornales. This phylogeny revealed novel phylogenetic relationships different from previous findings from analyses including less sampling of species and less DNA sequence data. 2. Robust estimation of divergence times of the order Cornales and the age of its constituent families was obtained. 3. Results of biogeographic analysis of Cornales including fossil distributions suggested a wide distribution of the ancestor in the Cretaceous. Including and excluding fossils in the biogeographic analysis resulted in dramatic differences on the center of origin of Cornales, arguing for the importance and careful uses of fossil data in biogeographic studies. 4. Comparison of developmental pathways among Cornus species suggested that condensed inflorescences (e.g., head and umbels) in Cornus evolved from elongated ancestor via independent developmental changes. 5. Investigation of bract development and B-class MADS-box genes revealed indevelopent evolution of petaloid involucral bracts in the flowering dogwood (Cornus florida) and little dogwood (Cornus canadensis). 6. A genetic transformation system has been established for the little dogwood bunchberry C. canadensis. This has allowed experiments of functional analyses of floral and inflorescence genes (e.g., silencing and over expression). 7. Molecular phylogenetic and biogeographic study of Philadelphus (Hydrangeaceae) was conducted; results provide evidence for testing the morphological classification scheme. Manuscript is in preparation. In summary, the studies addressed fundamental questions in evolutionary biology. The findings from the project study contributed new knowledge to the understanding of plant biota, particularly on the origin and evolution of the dogwoods and relatives. Results of the genetic studies of inflorescences have important potential for horticulture and agriculture industry. The resources and molecular methods established for the Cornales study faciliated similar investigations of other taxa.
Publications
- Harris, WK, SR Manchester, and QY(J) Xiang. 2012. Accounting for phylogenetic and optimization uncertainty and fossil distribution in biogoegraphic analysis of Cornales using Statistical Dispersal-Vicariance Analysis Software. Systematic Biology. In preparation.
- Harris, WK, and QY(J) Xiang. 2012. Inferring the Biogeographic Origins of Inter-Continental Disjunct Endemics using A Bayes-DIVA approach Journal of Sysematics and Evolution. Invited paper. In preparation.
- Feng, CM, QY(J) Xiang, RG Franks (Co-corresponding authors). 2011. Phylogeny-based developmental analyses illuminate evolution of inflorescence architectures in dogwoods (Cornus s. l., Cornaceae) New Phytologist. 191:850-869. Cover page. (Xiang and Franks are co-corresponding authors).
- Feng, CM, X Liu, Y Yu, WH Zhang, DY Xie, RG Franks, and QY(J) Xiang. 2012. Independent developmental origins and divergent B-class MADS-box gene expression patterns in petaloid bracts of Cornus s. l. (Cornaceae). New Phytologist. In revision.
- Feng, CM, X Liu, Y Yu, WH Zhang, DY Xie, RG Franks, and QY(J) Xiang. 2012. Alteration in selection, co-evolution, and expression of MADS-box B-class genes after gene duplication in dogwoods (Cornus s. l.,Cornaceae). Molecular Biology and Evolution. In preparation.
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Progress 10/01/09 to 09/03/10
Outputs
OUTPUTS: OUTPUTS: Results were disseminated via oral presentations at annual conference of Botanical Society of America, annual conference of American Society of Plant Taxonomist, seminars at Appalachain State University and Zhejiang University, International Conference on New Frontiers in Plant Systematics and Evolution in Beijing, lectures for NCSU Systematic Botany course and Plant Biology Study Abroad course in China. Results on study of Cornelian cherry fossils (of the dogwood family Cornaceae) were published (see below). A manuscript summarizing the findings of phylogenetic relationships and divergence times of the order Cornales was submitted for publication in journal of "Molecular Phylogenetics and Evolution". Manuscripts reporting results on biogeographic history of the order and those on inflorescence development and evolution are in preparation for publication. PARTICIPANTS: Individuals worked on the project: Graduate students: Wendy Harris, Chunmia Feng,and Ashley Brooks, Yuelong Guo Research specialist: Xiang Liu Students and postdocs benefit for training and professional development: Graduate students: Wade Wall, Chunmiao Feng, Ashley Brooks, Wendy Harris, Yuelong Guo Visiting graduate students: Yi Yu, Juan Liu Postdoctoral students: Norman Douglas Under graduate students: Alicia Smith, Esther Ichugu Collaborators: Qiaoping Xiang, Institute of Botany, Chinese Academy of Sciences, China Stephen Manchester, University of Florida TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: The project expanded to include a developmental and genetic study of important traits of the plants, especially on the floral and inflorescence development and evolution, using an integrative approach combining phylogenetics, evolution, development, gene expression and genetic transformation.
Impacts
1. The phylogenetic analyses resulted in a well-supported phylogeny of Cornales. This phylogeny revealed phylogenetic relationships different from previous findings from analyses including less sampling of species and less DNA sequence data. 2. Robust estimation of divergence times of the order Cornales and the age of its constituent families was obtained. The divergence time estimations were found to be substantially sensitive to the number and position of the nodal calibrations and data partitions, but robust to taxon sampling within families. The findings of 1 + 2 were summarized in a manuscript for publication. 3. Results of biogeographic analysis of Cornales including fossil distributions suggested a wide distribution of the ancestor in the Cretaceous. Including and excluding fossils in the biogeographic analysis resulted in dramatic differences on the center of origin of Cornales, arguing for the importance and careful uses of fossil data in biogeographic studies. Results are in preparation for publication. 4. Fossil fruits confirmed that cornelian cherries were established in the Northern Hemisphere in the Early Tertiary. Via comparison of sections of fossil and extant fruits, the oldest known member of the subgenus, Cornus piggae sp. n., was described based on fossil fruit from the late Paleocene of North Dakota. The new species differs from the extant species and fossil fruits from the Early Eocene London Clay by having much thinner external walls and lower locule number. Comparison with fruits of extant cornelian cherries indicates that the morphological range among the modern species is narrower than that seen in the Paleogene. 5. Comparison of developmental pathways among Cornus species suggested that condensed inflorescences (e.g., head and umbels) in Cornus evolved from elongated ancestor via independent developmental changes. 6. The established regeneration system for Cornus canadensis provided a platform for establishing a genetic transformation system of the species to aid function analysis of candidate genes controlling inflorescnece development in Cornales. 7. Molecular phylogenetic and biogeographic study of Philadelphus (Hydrangeaceae) was conducted; results provide evidence for testing the morphological classification scheme. Manuscript is in preparation. In summary, the studies addressed fundamental questions in evolutionary biology. The findings from the project study contributed new knowledge to the understanding of plant biota, particularly on the origin and evolution of the dogwoods and relatives. Results of the genetic studies of inflorescences have important potential for horticulture and agriculture industry. The resources and molecular methods established for the Cornales study faciliated similar investigations of other taxa.
Publications
- Xiang, QY(J), DT Thomas, and QP Xiang. 2011. Resolving and dating the phylogeny of Cornales- effects of taxon sampling, data partitions, and fossil calibrations. Mol. Phylogen. Evol. Revision in Review.
- Douglas, N. W Wall, QY(J) Xiang; T Wentworth, W Hoffmann, M Hohmann. 2011. Recent vicariance and the origin of the rare, edaphically specialized Sandhills Lily, Lilium pyrophilum (Liliaceae): evidence from phylogenetic and coalescent analyses. Molecular Ecology. In revision.
- Boufford, DE, CX Fu, QY Xiang and Y P Zhao. 2010. Observations on Buckleya (Thesiaceae ) in China. J. Bot. Res. Inst. Texas 4(1): 281-286.
- Manchester, SR, QY (J) Xiang, and XP Xiang. 2010. Fruits of Cornelian cherries (Cornaceae: Cornus Subg. Cornus) in the Paleocene and Eocene of the Northern Hemisphere. International Journal of Plant Sciences.171: 882-891.
- Wall, AW, NA Douglas*, QY(J) Xiang, WA Hoffmann, TR Wentworth, and MG Hohmann. 2010. Evidence for range stasis during the latter Pleistocene for the Atlantic Coastal Plain endemic genus, Pysidanthera Michaux. Molecular Ecology 19: 4302-4314.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: 1. Additional phylogenetic analyses using DNA sequences from seven regions of chloroplast and nuclear genomes were conducted for Cornales. Results from different phylogenetic methods and different data partiones were compared. Resultes were submitted for publiccation. 2. Divergence times of lineages were estimated to understand the tempo of evolutionary events during the diversification of the order by taking into account of phylogenetic uncertainty, fossil uncertainty. Effects of species sampling, fossil calibration using fossils, and genes on the estimates were examined. Results were submitted for publication. 3. A new statitical approach for infering biogeographic history under phylogenetic uncertainty was developed and tested. Results has been published in a professional journal and presented as a poster at International Biogeographic Conference. 4. Effects of fossils on reconstructing biogeographic histories were explored in three lineages. Results were presented in the 4th International Biogeographic Conference in Mexico. 5. Additional analyses of the genetic data for Nyssa species using newly developed methods were conducted. Preparation of manuscript is underway. 6. Developing a tissue culture and transformation system for Cornus canadensis for studying the molecular basis of character evolution in Cornus. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
1. The phylogenetic analyses resulted in a well-supported phylogeny of Cornales using the different methods. This phylogeny revealed a phylogenetic relationships different from previous findings from analyses including less sampling of species and DNA sequence data. It supported an alignment of Cornus-Alangium with the African genera Curtisia and Grubbia, while the aquatic African genus Hydrostachyaceae is aligned with the Hydrangeaceae and Loasaceae. 2. The divergence time analyses using the recent method (named BEAST) found Cornales evolved in the early Cretaceous and diversified into six major families in the mid and late Cretaceous time. The divergence time estimations were sensitive to the number and position of the nodes calibrations on the phylogeny and the genes used, but estimations of time for the early divergence events of the order and ages of major families were fairly robust to taxon sampling if species selection was phylogeny-based to represent each major lineage. These results suggest caution in application of divergence time data, and analysis using multiple calibration points and multiple data sets with proper sampling is needed to derive reliable estimations. Findings of 1 + 2 were summarized in a manuscript for publication which is currently in review: Xiang, Qiu-Yun (Jenny), David T. Thomas, Qiao-Ping Xiang. Submitted. Resolving and dating the phylogeny of Cornales- effects of taxon sampling, data partitions, and fossil calibrations. Molecular Phylogenetics and Evolution. 3. The new statitical approach for infering biogeographic history under phylogenetic uncertainty provide an alternative and simple tool the to existing methods for infering biogeographic histories under phylogenetic uncertainty. The method was automated in a new computer software S-DIVA that is free to users. 4. We found that including and excluding fossils in the phylogeny for biogeographic analysis can result in dramatic inferences on the history, argued for the importance and careful uses of fossil data in biogeographic studies. 5. The new analyses of the genetic data for Nyssa species revealed little genetic divergence between Nyssa sylvatica and N. biflora, no genetic bottlenecks during the glaciation, and a possible assymmetrical gene flow between the two taxa. 6. A system for regenerating Cornus canadensis through oganogenesis has been established. The transformation system is under optimization. In summary, the findings from the project contributed new knowledge to the understanding of fundametnal questions in evolutionary biology, in addition to enhancing our knowledge in the origin and evolution of dogwoods and relatives. Results of the research also have general interest to the public and research communities of plant biogeography and evolution.
Publications
- Feng*, CM, SR, Manchester, QY(J) Xiang. 2009. Phylogeny and biogeography of Alangiaceae (Cornales) inferred from DNA sequences, morphology, and fossils. Molecular Phylogenetics and Evolution. 51:201-214.
- Feng*, CM, R. Qu, LL Zhou, DY Xie, and QY(J) Xiang. 2009. Shoot regeneration of dwarf dogwood (Cornus canadensis L.) and morphological characterization of the regenerated plants. Plant Cell Tiss Organ Cult. 97:27-37.
- Harris, AJ and QY(J) Xiang, 2009. Estimating ancestral distributions of lineages with uncertain sister groups: a statistical approach to dispersal vicariance analysis and a case using Aesculus L. (Sapindaceae) including fossils. Journal of Systematics and Evolution. 47:349 368.
- Harris* AJ, QY(J) Xiang, and David Thomas. 2009. Molecular and Morphological Inference of the Phylogeny, Origin, and Biogeographic History of Aesculus L. (Sapindaceae or Hippocastanaceae). TAXON 58:1-19.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Analyses to determine if rate of molecular evolution is related to rates of speciation and morphological changes in dogwoods (Cornus) found, in general, no relationships between rate of nucleotide substitutions and rate of speciation, but a possibile link between speciation and nonsynonymous substitions in chloroplast DNA exists. A positive relationship between rate of molecular evolution and rate of morphological changes were detected in the genus, which is specially pronounced in the dwarf dogwood group (the bunchberries). Furthermore, analyses to identify causes underlying variation of rate of molecular evolution revealed that a combination of factors including variation in mutation rate, selectin force, and genetic drift are responsible for the observed variation in rate of nucleotide substitutions among dogwood lineages. These results were published. Analyses of tracking evolutionary histories of key morphological characters and biogeographic range evolution using various methods found substantial sensitivity of results to the nature of characters as well as to the methodologies used. Results were published. Analyses of molecular evolution and tracing evolutionary histories of morphological characters over the reconstructed phylogeny of the entire Cornales are in progress. Biogeographic analysis of the entire order using the most recently published model-based method implementing fossils is also in progress. The results will be presented at the annual conference of Interntionla Biogoegraphic Society in January 2009. A genetic analysis of eastern North American Nyssa species(a member of the Cornales group) has been nearly completed and found a pattern different from those reported from other tree species in the eastern US. Results were presented at annual Botantical Society of America in Vancouver in July 2008. Fossil leaves of Cornus from the early Tertiary was reviewed and confirmed with microscopic study. Previously errorneously identified fossils of Cornus were corrected. Results were in press for publication. Investigation of fruit fossils of cornelian cherries by sectioning is finished and manuscript is under preparation. PARTICIPANTS: Participants of the project: Stephen Manchester (Collaborator from U. Florida), David Thomas and Xiang Liu (research technicians); CHunmiao (Mia) Feng (Ph.D. student) Research Collaborators on the project: Stephen Manchester, U. Florida Jeffrey Thorne, Statistic and Genetics, North Carolina State University Training of graduate students: Chunmiao (Mia) Feng, Ashley Brooks Training of undergraduate students: Anthony Oestergg R. Ostertag, Gayatri pongur Snigdha TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
1. Finding the key characters to confirm a leaf fossil to Cornus. Identification of leaf fossils has been difficult due to similarities of leaves across unrelated groups. Via collaboration with investigators in University of Florida and microscopic examination of fossil leaves, we found that the two-armed hairs with calcium carbonate deposite , charisteristic of the dogwood genus, were well preserved on fossils and can be used as a reliable character in association with venation pattern to identify dogwood leaf fossils. Using this feature, we clarified the mis-identification of some leaf fossils that previously considered belonging to Cornus. This finding has important impact to the reconstruction of biogeographic history of the genus, which is in turn, relevant to the understanding of biogeography of plant biota as a whole. It also demonstrated the utility of microscopic features in fossil identification. 2. Various approaches are available for reconstructing ancestral distributions and ancestral character state. The finding that results are substantially senstive to choice of method raises caution in such studies and has general interest in the community of evolutionary biology. 3. Causal factors underlying elevated rate of moleclar evolution in a particular lineage has often been difficult to identify and are usually poorly understood. Via collaboration with investigators in statistics and application of new methodologies, we were able to tease apart the various potential factors influencing the rate of nucleotide substitutions. The study represents one of the few detailed analyses aiming to unravel causal factors of rate variation among closely related species. 4. Relationships of rate of molecular evolution to rate of morphologial evolution and species richness have long been controversial. Through careful comparative analyses of several genes on the phylogeny, we found a pattern of positive relationship of rate of nucleotide substitutions to morphological changes, but no general pattern, although maybe a localized, pattern of positive relationship to species richness. This finding adds new knowledge to these fundamental questions in plant evolution and suggests complexity of relationships among biological factors in evolution. In summary, the findings from the project contributed new knowledge to the understanding of fundametnal questions in evolutionary biology, in addition to enhancing our knowledge in the origin and evolution of dogwoods and relatives. Results of the research also have general interest to the public and research communities of plant systematics and evolution.
Publications
- Xiang QY(J), JL Thorne, TK Seo, WH Zhang, DT Thomas, RE Ricklefs. 2008. Rates of nucleotide substitution in Cornaceae (Cornales) - pattern of variation and underlying causal factors. Molecular Phylogenetics and Evolution. 49:327-342.DOI: http://dx.doi.org/10.1016/j.ympev.2008.07.010
- Xiang QY(J) and DT Thomas. 2008. Tracking character evolution and biogeographic history through time in Cornaceae - Does choice of methods matter Journal of Systematics and Evolution. 46:349-374.
- Manchester, SR, QY(J) Xiang, TM Kodrul, and M Akhmetiev. 2009. Leaves of Cornus (Cornaceae) from the Paleocene of North America and Asia confirmed by trichome characters. International Journal of Plant sciences. come out in January issue.
- Zhang, WH, QY (J) Xiang, DT Thomas, BM Wiegmann, MW Frohlich and DE Soltis. 2008. Molecular evolution of PISTILLATA-like genes in the dogwood genus Cornus (Cornaceae). Molecular Phylogeny and Evolution. 47:175-195.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Investigation of phylogenetic relationships among genera of Cornales using molecular data was finished. The phylogeny was used as the basis to investigate biogeographic history and determine the timing of major evolutionary events during the Cornales radiation. Fossils of Cornales were studied to provide information in the investigation of the Cornales evolutionary history. A part of the results were presented at annual BSA meeting in Chicago and published in scientific journals. Two manuscripts on fossils are in preparation, and one manuscript on the phylogeny of Alangium (the sister of Cornus) is in review and one on phylogeny of Cornales is in preparation.
PARTICIPANTS: Participants: David Thomas, Wenheng Zhang, Mia Feng, Stephen Manchester. Collaborators: S.R. Manchester (U. Florida), Qiaoping Xiang (Institute of Botany, Chinese Academy of Sciences, Beijing). Training: Wendy K. Harris (MS student) Mia Feng (Ph.D. student) LaDonna Joseph (undergraduate student) Lidsey Perry (undergraduate student)
Impacts
1. Discovered the occurrence of Tertiary fossils of Curtisia, a small genus now confined to southern Africa, in Europe. This finding has important implication in the past distribution of the genus and the understanding of biogeographic history of Cornales. 2. Clarified relationships among the Cornales genera, which include many popular ornamental plants (e.g., Hydrangea, Davidia, Dogwoods, etc.) and the medicinally important Campotheca, which produce camptothecin, a compound proved to be anti-tumor effective drug. The phylogeny dipicting the relationships of Cornales genera provides a basis to guide the searching of new plant sources for anti-turmor natural products. 3. Due to the wide distribution of Cornales taxa in both northern and southern hemispheres, the biogeographic analysis of Cornales will shed light in our understanding of floristic exchanges among regions of Laurasia and between Laurasia and Gondwana land.
Publications
- STEVEN R. MANCHESTER1, QIU-YUN (JENNY) XIANG and QIAO-PING XIANG. 2007. Curtisia (Cornales) from the Eocene of Europe and its phytogeographical significance. Botanical Journal of the Linnean Society. 155:127-134. With 4 figures.
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