The U.S. National Arboretum's Floral & Nursery Plants Research Unit conducts research that has significant impact on many areas of horticulture, the environment, gardening, and the U.S. consumer. For specific research details, please see the Scientists and
their Specialties pages.
Important research accomplishments include the following
(with a summary of more recent accomplishments listed further below):
Development of New Floral Plants & Production Protocols
One Patent issued on a broad-spectrum potyvirus monoclonal antibody now available in a commericial diagnostic virus-detection kit.
Six Patents issued relating to the control of plant pests and pathogens with by-products of neem seed.
One Patent issued for clove oil as a fungicide to control soilborne and foliar pathogens.
One Patent issued relating to enhanced insect resistance in plants genetically engineered with a plant hormone gene.
EPA approved registration of Neem oil as a biopesticide for non-food uses.
One Patent application relating to regeneration of roses from tissue culture.
One Patent application on five cultivars of Ornithogalum.
Developed and utilized biochemical tests that more accurately identify true species of birch. Determined species distribution of specific plant compounds responsible for resistance or susceptibility to certain birch, lilac, and ash insect pests.
Developed DNA molecular markers to identify and differentiate species, hybrids, cultivars, and genotypes of various herbaceous and woody ornamentals.
Biorationals from a variety of plants, including Ardisia, Neem and Nicotiana, were developed and evaluated as biopesticides for the control of insects and fungi. New management practices for the control of whiteflies on ornamentals were developed.
Developed molecular tools for the successful detection and differentiation of (a) impatiens necrotic spot tospovirus, a serious viral pathogen of many ornamental and vegetable crops; (b) diverse strains of plum pox potyvirus, a serious viral pathogen of Prunus species; (c) viruses infecting Pelargonium; and (d) pathogenic and saprophytic isolates of Botryosphaeria, a pathogen of redbud (Cercis).
Developed molecular tools to detect the bacterial leaf scorch pathogen (Xylella fastidiosa) in: (a) new shade tree and other ornamental hosts; and (b) new insect vector species, including leafhoppers, spittle bugs and treehoppers.
Developed transformation systems to genetically engineer plants, including Gladiolus and Easter lily, to express nucleic acids, proteins and antibodies, as a means to obtain insect- and virus-resistant plants.
Produced monoclonal and polyclonal antibodies to several plant viruses including: Tomato spotted wilt; Impatiens necrotic spot; Cucumber mosaic; Cymbidium mosaic; Carnation necrotic fleck; Pelargonium line pattern; Lily symptomless; and Prune Dwarf; and many potyviruses). Antibodies have been donated to the American Type Culture Collection for public distribution and/or released to Agdia, Inc for commercialization (as part of a CRADA), or to the California and North Carolina State Department's of Agriculture for use in testing and certification of stone fruit trees.
Investigated the use of x-ray technology to assess seed germination of woody plants.
Was the first to discover that American elm consists of two genetically distinct populations, which could lead to new sources of genes for disease resistance and tolerance to urban stresses.
Developed a method to study proteomics of an important soilborne fungal plant pathogen Rhizoctonia solani G-4 to investigate its biology and pathology and identified several pathogenicity-associated genes through Expressed Sequence Tag (EST) analysis.
Developed an efficient Agrobacterium-mediated transformation protocol to label the fungus that causes gladiolus wilt with green, yellow and cyan fluorescent genes so that its movement and gene functions can be readily traced in the plant.
Demonstrated that the transgenic expression of an antimicrobial milk protein lactoferrin in plants imparts resistance to Rhizoctonia solani.
Generated interspecific hybrids between Carolina hemlock (Tsuga caroliniana) and several Asian species, as well as interspecific Asian hybrids. Inoculation studies in field- and nursery-grown plants have shown the hybrids to have high levels of resistance to the invasive hemlock woolly adeligid.
Improved a biovar test for Ralstonia solanacearum, and discovered the effectiveness of clove oil on plant pathogenic bacteria and bacterial wilt of tomato and geranium caused by R. solanacearum.