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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Taxonomic evaluation of the genus Pantoea based on a multigene approach

Brady, Carrie Louise 18 September 2008 (has links)
The genus Pantoea contains seven validly-published species, which are primarily known as plant-associated or phytopathogenic bacteria, but some have also been linked with human infections. Over the past six years, there have been increasing isolations of Pantoea strains from a range of hosts and locations which can not be conclusively identified. In South America and Uganda, Pantoea strains were isolated from Eucalyptus infected with bacterial blight. In South Africa, Pantoea strains were isolated from maize suffering from brown stalk rot and from onion seed. This has highlighted the need for a rapid, molecular-based technique to conclusively characterize these Pantoea strains. In the literature, two key taxonomic problems were identified within the genus Pantoea. The first involves three species isolated from fruit and soil samples in Japan, namely P. citrea, P. punctata and P. terrea, known as the “Japanese” Pantoea species. A recent review of the genus noted that Pantoea can be separated into two groups: the Pantoea “core” containing P. agglomerans, P. ananatis, P. dispersa and P. stewartii and the “Japanese” species. It was also stated that more taxonomic work is required to justify the assignment of the “Japanese” species to the genus Pantoea. The second taxonomic issue raised concerns over four DNA hybridization groups from a study of a large number of clinical strains belonging to the Erwinia herbicola-Enterobacter agglomerans complex. It had been previously suggested that these four DNA hybridization groups should belong to the genus Pantoea. The phylogenetic relationship between the Pantoea “core” species, the “Japanese” species and the four DNA hybridization groups is not clear. Multilocus sequence analysis (MLSA) was selected for a taxonomic study of the genus Pantoea The MLSA scheme was based on the sequences of four housekeeping genes: rpoB, atpD gyrB and infB. It was found that a phylogenetic tree of the concatenated sequences could differentiate all seven validly-published species as well as ten groups of strains from Eucalyptus, maize, onion, flowering shrubs and clinical isolates. The phylogenetic trees also confirmed the separation of Pantoea into two groups of species and indicated a close affiliation of the “Japanese” species with the genus Tatumella The clusters observed in the MLSA phylogenetic trees were confirmed by DNA-DNA hybridization. Using the MLSA data for support, four novel species were proposed from plant hosts: Pantoea vagens, Pantoea eucalypti, Pantoea deleyii and Pantoea anthophila. Four additional species were proposed for the clinical strains from the Erwinia herbicola-Enterobacter agglomerans complex, contained in three DNA hybridization groups: Pantoea septica, Pantoea eucrina, Pantoea brenneri and Pantoea conspicua. Phenotypic information and DNA-DNA hybridization values confirmed that the “Japanese” species were more similar to Tatumella than to Pantoea. This was demonstrated phylogenetically in the MLSA trees and gave support to transfer the “Japanese” species to the genus Tatumella. Additionally, a novel species was proposed for strains thought to belong to T.citrea, causing pink disease of pineapple: Tatumella morbirosei. Therefore, MLSA was not only proven to rapidly and successfully identify Pantoea strains, but also resolved the two major taxonomic issues within the genus. Please cite as follows: Brady, CL 2008, Taxonomic evaluation of the genus Pantoea based on a multigene approach, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-09182008-142751/ > Copyright / Thesis (PhD)--University of Pretoria, 2009. / Microbiology and Plant Pathology / unrestricted
22

Rust of antirrhinum

Doran, William Leonard 01 January 1917 (has links) (PDF)
The cultivated snapdragon ( Antirrhinum majus 3 .) is a perennial or biennial under culture, it is a member of the family Scrophulariaceae. The plant was introduced here from Europe. As an escape from gardens, it is rare in New England. The snapdragon has been a popular garden flower for two hundred years, but it is only within the last ten years that it has been grown to any extent as a greenhouse crop. There has been an increasing demand for it as a cut flower, and consequently an increasing amount of glass has been devoted to its culture. As a florist's crop, the snapdragon may be classed as about equal in importance to mignonette, schizanthus, stocks, pansies, and primulas (Nehrling, 1914), varying, of course, in different localities.
23

A study of the factors influencing the selective action of phytotoxic compounds : a thesis

Bruce, R. S. January 1955 (has links)
No description available.
24

Biodiversity, ecology and taxonomy of saprobic fungi on palm fronds

鄭遠技, Yanna. January 2001 (has links)
published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy
25

Analysis of pathogenicity of Pyrenopeziza brassicae, cause of light leaf spot of brassicas

Batish, Suman January 1992 (has links)
No description available.
26

The Erysiphaceae of Kansas

Long, Gary Mack January 2011 (has links)
Digitized by Kansas Correctional Industries
27

Cultivar mixtures and the control of plant pathogens

Helps, Joseph Christopher January 2014 (has links)
No description available.
28

Biodiversity, ecology and taxonomy of saprobic fungi on palm fronds /

Yanna. January 2001 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references.
29

The effect of amplitude and frequency of temperature fluctuations on growth of Sclerotium bataticola and Verticillium dahliae and on disease development in their host plants.

Wilanowski-Guzdziol, Barbara. January 1974 (has links)
No description available.
30

Oosporogenesis and chlamydospore formation in Phytophthora capsici

Uchida, Janice Y January 1984 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1984. / Bibliography: leaves [82]-88. / Photocopy. / Microfilm. / viii, 88 leaves, bound ill. 29 cm

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