Associate Curator and Head of Section Cynthia Morton
Overall Research Objectives
My overall research objectives and planned direction remain constant: to integrate my own research skills in molecular systematics, morphology, genomics, and developmental biology to peruse the questions raised from phylogenetic analysis; to combine this with researchers who are developing new methods in bioinformatics, and to apply this information to establish robust applied phylogenetic or phylogenomic hypotheses for a variety of large economically important groups such as Rutaceae and Lecythidaceae. This will allow students to be broadly trained in applied systematics or phylogenomics so that they can accept the challenging questions we are now raising. This synthetic approach to systematics will not only provide useful training for students but will prove productive for me as a researcher and to advance the field of phylogenetics.
Phylogeny of Rutaceae
Most of my current research involves the family Rutaceae, a large tropical group containing many members of economic importance such as the citrus fruits of commerce (lemon, grapefruits, oranges, mandarins, etc.). My initial examinations of molecular sequences for the rbcL and the atpB genes demonstrated the inadequacies of the current taxonomic system (see publications). Due to the low resolution of the above trees, I continued to sequence two additional genes to provide a well-resolved tree containing forty-five Rutaceae taxa. From this information I have been investigating the relationships of the subfamily Aurantioideae using both molecular and morphological data in a phylogenetic context. I have also worked on the evaluation of Inter-Simple Sequence Repeat (SSR) for distinguishing Citrus germplasm and for identification of sweet orange (Citrus sinensis) adulteration. From both the phylogenetic and agricultural analysis, I have become aware that fundamental studies involving genomics need to be completed to address more thoroughly these taxa and the economic traits. Currently I am involved with several colleagues to obtain funding to complete a physical map for Citrus and generating EST to hybridize to this map.
Genomics of Mucuna
Since 1999 I have been working with Dr. Weaver in the Agronomy Department at Auburn University on the assessment of genetic diversity of the rotational crop Mucuna (velvet bean). This crop is important because of its nitrogen fixing capabilities and its potential use for cattle fodder. Until this past spring I had been supervising a PhD student, Vic Capo-chichi, in morphological and AFLP techniques. During the past several years, Dr. Capo-chichi and myself completed the laboratory work, presented the results at two international meeting, and published in the journal Theoretical and Applied Genetics. Currently we have been working on the F1 and F2 populations in constructing a genomic map for Mucuna. These results are submitted with the journal of Theoretical and Applied Genetics.
At the beginning of 2000, I began working with Drs. Saunder and Lee in the Geology Department on groundwater geochemistry, and microbiology of an underground aquifer in Central-South Alabama. A graduate student, Ivy Thomson, and myself have been working for the past several years on the microbiology to examine the effects of sulfate-reducing bacteria of a heavy metal contaminated aquifer. From the preliminary data we have written several grants and have been successful in receiving funding. We have one paper submitted containing our results.
Phylogenetics of Lecythidaceae
In addition, I have collaborated with Dr. Prance, Dr. Mori (New York Botanical Garden), and Ms. Thorburn in formalizing a new taxonomic alignment for the Lecythidaceae using evidence from rbcL and trnL sequence data and morphological data. This study identified that more floral developmental studies were needed on this very diverse group of plants. Currently we have been examining the expression of the homeotic gene FIMBRIATA (specific in petal identity) in members of Lecythidaceae with variable flower morphology. To date we have designed primers, amplified, sequenced, and aligned the FIMBRIATA gene for two species of Lecythidaceae.
Phylogeny of Chrysobalanaceae
In collaboration with Ms. Dissanayake, and Drs. Prance (Director of the Royal Botanical Garden), an examination of Chrysobalanaceae has been underway for the past several years. Phylogenetic research on the Chrysobalanaceae using molecular, anatomical and biochemical data has been completed for the fulfillment of a PhD thesis. Currently manuscripts are being submitted based on separate and combined analysis using all data.
Phylogeny of the Angiosperms
Over the past several years I have been involved with a very large molecular project assessing seed plant phylogeny using the atpBeta chloroplast gene. The study expanded in collaboration with Chase (Kew) and others using the atpB, and rbcL gene sequences to investigate the phylogenetic patterns among the eudicots (see publications). This new phylogeny has been completed by a group of international collaborators and is the first multi-authors classification for the angiosperms using molecular data (APG group centered in Uppsala).
Phylogeny of Ebenales
As a NATO postdoctoral student I continued my thesis work on the order Ebenales using molecular systematics, more precisely using rbcL chloroplast gene. My primary purpose for using molecular systematics was to guide future studies of morphology and anatomy and to evaluate the reliability of floral and leaf features, the primary features used in Ebenales taxonomy. With several collaborates we completed a 25 family (90 taxa) level analysis, encompassing the Ebenales, using the conserved rbcL gene. This analysis found the Ebenales to be polyphyletic. The rbcL tree identified the Ebenales to be distributed among several major subclades. More recently I have been collaborating with Dr. Peter Fritsch regarding the phylogeny of the Styracaceae based on morphological and molecular characters. Dr. Fritsch and myself completed a paper entitled “Phylogeny of the Styracaceae based on morphology and molecular data” which examines both the phylogenetic and biogeographical history of this family.