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Taxonomy and population biology of selected Ceratocystis spp. with hat-shaped ascosporesVan Wyk, Marelize. January 2004 (has links)
Thesis (M.Sc. (Department of Microbiology and Plant Pathology ))--University of Pretoria, 2004. / Includes summary. Includes bibliographical references.
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Ceratocystis species in southern and eastern Africa with particular reference to Ceratocystis albifundusHeath, R.N. (Ronald Natale) 22 October 2009 (has links)
Thesis (PhD)--University of Pretoria, 2011. / Genetics / Unrestricted
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Phylogenetic relationships and taxonomy of species in ceratocystis sensu latoVan Wyk, Marelize January 2013 (has links)
Ceratocystis is a genus of Ascomycete fungi residing in the family Ceratocystidaceae (Order:
Microascales; Class: Sordariomycetes). Species of Ceratocystis are best-known as woundinfecting
fungi, which are mostly carried by insects. Little is known regarding the basis of the
relationship between insects and Ceratocystis spp., but in some cases it might extend to levels of
mutualism. The taxonomic history of the genus is complex and has, during the course of more
than 100 years, been intertwined with several other genera. However, in recent years, the
resolution arising from DNA sequence comparisons has resulted in the recognition of at least four
major groups within Ceratocystis. major groups within Ceratocystis.
Ceratocystis species in the broad sense (including Ambrosiella) represent ecologically diverse
assemblages, including four very clearly defined groups. One of these groups, which I refer to as
the C. coerulescens sensu lato (s.l.) group, which mainly cause blue-stain in timber, is the only
group that is known to have a very close association with conifer-infesting bark beetles. Perhaps
the best-known group is the C. fimbriata s.l. assemblage of species, which includes a large
number of serious pathogens of angiosperms, mostly trees. This group also includes nonpathogenic
wound-infecting species. There are no specific insect vectors of these species but they
produce fruity aromas, which attract a wide range of insects such as flies, ants, mites and nitidulid
beetles that aid in their dissemination to fresh wounds. The majority of the species in the C.
fimbriata s.l. group are primary pathogens causing cankers that can girdle and eventually kill the
affected areas. The third group of fungi in the broadly defined Ceratocystis s.l. is the C.
moniliformis s.l. group. This group includes only saprophytes that, similar to species in C.
fimbriata s.l., produce fruity odours and they are thus vectored by opportunistic insects including
flies and nitidulid beetles. Ambrosiella spp. are broadly included in the assemblage
accommodating Ceratocystis spp. These fungi have no known sexual state and they live in
obligate symbioses with ambrosia beetles (Scolytinae). Ceratocystis and its relatives have had a complex taxonomic history ever since the genus was
first described by Halstead in 1890. Much of the confusion regarding their taxonomy has arisen
from a dependence on morphology for classification and the fact that these and other fungi have
undergone convergent evolution related to their association with insects. Until the late 1990s,
genera and species in this group were described based only on morphology, although the importance of various morphological features was strongly debated. However, between 1950-
1999, a turning point arose in the way that these fungi were recognised. This change emerged
first from the inclusion of various chemical approaches and then later the application of
molecular techniques to identify them. The most dramatic changes have come with the
widespread application of DNA sequence comparisons, which were first applied to the group in
the early 1990’s. This made it possible to define higher-order relationships and brought the first
clear evidence that species in Ceratocystis and Ophiostoma were phylogenetically unrelated. A
complete taxonomic history of this group is provided in the timeline presented in Table 1. This thesis deals primarily with two groups in the broadly defined Ceratocystis. These are species
in the C. moniliformis s.l. and the C. fimbriata s.l. complexes, but with a considerably greater
focus on the C. fimbriata s.l. complex. Morphologically, species in the two complexes are easy to
distinguish from each other even though they share some common characteristics. Species in both
complexes have hat-shaped ascospores and both have the anamorphic characteristics typical of
species in the genus Thielaviopsis. The ascomatal bases are mostly globose to sub-globose with
elongated necks. There are two main features that species in the C. moniliformis s.l. complex
have that are not observed in the C. fimbriata s.l. complex. One is a very distinct “collar-like”
structure at the base of the ascomatal necks of species in the C. moniliformis s.l. complex. These
“collar-like” structures result in the necks being fragile and they dislodge from the ascomatal
bases very easily. The other distinct characteristic is that these fungi have conical spines on their
ascomatal bases, giving the structures a textured appearance. This is in contrast to the ascomatal
bases in the C. fimbriata complex that are smooth. Species in the C. moniliformis s.l. complex are
non-pathogenic and cause only some sap-stain in the host tissues. The C. fimbriata s.l. complex
includes a large number of primary pathogens, mainly of trees but also including root crops. A
phylogenetic tree including all species in the C. fimbriata s.l and C. moniliformis s.l. complexes
is presented in Figure 1-3. In generating this tree, three gene regions i.e. the Internal Transcribed
Spacer Region including the 5.8S rRNA operon (ITS), part of the the Beta-Tubulin 1 (BT) gene
and part of the Transcription Elongation Factor 1 alpha (TEF) gene have been combined to
represent species in the two complexes. Both Bootstrap as well as Bayesian analyses were run to
obtain confidence intervals. More detailed methods are presented in the legends to the trees. Chapter one of this thesis presents a review of the groups in Ceratocystis. With the aid of DNA
sequence comparisons, three phylogenetically distinct groups are identified. These groups are
characterised by three well-known species each now defined as a species complex i.e. the
Ceratocystis coerulescens complex, the C. moniliformis s.l. complex and the C. fimbriata s.l.
complex. Species of Ambrosiella are also recognised as representing a discrete and related group.
These three species complexes are not only differentiated based on DNA sequence comparison
but have distinct morphological features that distinguish them from each other. They are also
defined by having very distinct ecological roles in nature. Chapter 2 specifically reviews the key
literature dealing with the taxonomy of species in the C. fimbriata complex. This group is defined
by Ceratocystis fimbriata s.s., which was first described as a pathogen causing black rot on sweet
potato. Subsequent to the emergence of DNA sequencing techniques to define species, many new
species in the C. fimbriata s.l. complex have been defined and described. Chapters three and four of this thesis deal with a species of Ceratocystis collected from dying
Mango trees in Oman. A very serious disease known as Mango Sudden Decline disease was first
observed in Oman and has recently been subjected to intensive investigation. This led to a
recognition that a species related to C. fimbriata might be responsible for the disease of
Mangifera indica. As part of the process of identifying the causal agent of Mango Sudden
Decline, two Ceratocystis spp. were described. One is the previously described and nonpathogenic
C. omanensis residing in the C. moniliformis s.l. complex and the other is C.
manginecans, a virulent pathogen residing in the C. fimbriata s.l. complex (Chapter 4).
Chapters five through eleven of this thesis include the descriptions of new species in the C.
fimbriata complex that have emerged over a seven year period. These descriptions have all relied
strongly on DNA sequence based phylogenetic inference as well as morphology. It is important
to recognise, however, that the morphological features are very similar in most species and that
differences rely on the size ranges of key features in this group.
The genus Ceratocystis represents a complex of many species and is set to be sub-divided into at
least three discrete genera, not including Ambrosiella, which is also closely related and already
well-defined. Studies in this thesis began at a time when it became possible to define species of Ceratocystis based strongly on a phylogenetic concept. Thus, while morphological and ecological
features were taken into account, there has been a heavy reliance on DNA sequence comparisons.
It is likely that in coming years, new gene regions will be recognised that will allow a refinement
of genus and species boundaries. Furthermore, having access to whole-genome sequencing will
add deeply to our understanding of taxonomic relationships between these important and
fascinating fungi. It is my hope that the foundation provided by the studies incorporated in this
thesis will be useful as this new wave of study emerges. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Genetics / unrestricted
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Some aspects of the bionomica of two species of Xyleborus attacking Theorbroma cacao LBishop, Winans Orias, January 1900 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 72-75.
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The oak wilt fungus and its host I. The growth of the oak wilt fungus with various carbon, nitrogen, and vitamin sources. II. Host responses associated with the development of oak wilt /Beckman, Carl H. January 1953 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1953. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliographies: leaves [33], [59]-61.
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Isolation and identification of a coremia induction factor for Ceratocystis ulmi from elm woodTaylor, Paul Alan, January 1969 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
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The utilization of glucose carbon by five isolates of the fungus Ceratocystis ulmi /Higgins, Daniel Joseph January 1959 (has links)
No description available.
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Desenvolvimento de um novo método para o controle da podridão abacaxi em cana-de-açúcarLodo, Bruno Nascimento [UNESP] 06 February 2011 (has links) (PDF)
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lodo_bn_me_jabo.pdf: 200037 bytes, checksum: 3374cb8ac97e3177158a05ecc62ed985 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A expansão do período e a mecanização das etapas de plantio da cana-de-açúcar favorecem a ocorrência da podridão abacaxi causada por Thielaviopsis paradoxa, tornando-se necessária a busca por técnicas de manejo eficazes no controle da doença. Para tanto, foram realizados 4 ensaios. Inicialmente, foram testadas concentrações de 0, 102, 103, 104, 105, 106 e 107 conídios mL-1 de T. paradoxa inoculadas em 5 toletes de cana-de-açúcar com 1 gema cada por vaso. Foi avaliado o número de plântulas emergidas e calculado o índice de velocidade de emergência. Em um segundo ensaio, foi verificada a viabilidade do patógeno no solo dos vasos do ensaio anterior, sem irrigação por 4 meses, quando se realizou novamente o plantio, avaliando-se o número de plântulas emergidas. Para avaliar o controle da doença, em área de cana-planta, foram aplicados no solo ciproconazole + thiamethoxam (300 + 300 g do i.a. ha-1) e triadimenol + dissulfoton (600 + 3000 g do i.a. ha-1), com e sem incorporação em quatro épocas 6, 4, 2 e 1 mês antes do corte e plantio (ACP) das mudas. Os toletes foram retirados das áreas tratadas para a instalação de dois ensaios, um em vasos e outro em campo, sendo inoculandos com 107 conídios mL-1. Foram avaliados o número de plântulas emergidas e calculadas a porcentagem de germinação e a porcentagem de germinação em relação à testemunha. O delineamento foi em blocos casualizados em esquema fatorial 4 x 2 x 2 + 2 testemunhas com 4 repetições. Nos resultados dos ensaios observa-se que todas as concentrações do patógeno testadas foram eficientes para que ocorresse a doença. O patógeno permaneceu viável no solo por pelo menos 4 meses, provocando a doença, independente das concentrações testadas. A utilização de ciproconazole + thiamethoxam, independente do modo e da época de aplicação se mostrou eficaz no controle da doença, desde que o solo mantenha teor de umidade adequado após sua aplicação / The expansion of period and the steps mechanization of the cropping system of sugarcane favors the occurrence of pineapple disease caused by Thielaviopsis paradoxa, making necessary the search for effective management techniques to control the disease. To this end, four tests were done. Initially, concentrations were testing of 0, 102, 103, 104, 105, 106 and 107 conidia mL-1 of T. paradoxa inoculated in 5 sugarcane stems with a gem each per vase. The number of seedlings was evaluated and the index of germination speed was calculated. In a second experiment, the pathogen viability was verified in vases of the previous essay, without irrigation for 4 months, when it the planting again, the number of seedlings was evaluated. To evaluate the control of the disease, in area of first planting of sugarcane crop, in soil ciproconazole + thiamethoxam (300 + 300 g do i.a. ha-1) e triadimenol + dissulfoton (600 + 3000 g do i.a. ha-1) were applied, with and without incorporation in four time 6, 4, 2 and 1 month before cutting and planting (BCP) of stems. The stems were withdrew from of the treated areas for installation of two tests, one in vases and others in field, inoculating them with 107 conidia mL-1. The number of seedlings was evaluated and the germination percentage and germination percentage compared to check was calculated. The design was randomized block in a 4 x 2 x 2 + 2 checks with four replicates. The concentrations tested were effective to produce the disease. The pathogen remained viable in the soil for 4 months, causing the disease, regardless of concentration. The use of cyproconazole + thiamethoxam, regardless of the mode and time of application was effective in controlling the disease, since the soil has adequate moisture after application
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Mitochondrial genomes and concerted evolution in CeratocystisNaidoo, Kershney January 2013 (has links)
The objective of this study was to characterize the mitochondrial genomes of the species
within the genus Ceratocystis and investigate the evolutionary process of the ribosomal RNA
cistron found within these fungi. Ceratocystis incorporates a number of pathogenic species
affecting a variety of hosts, making the study of these fungi economically significant. The
fortuitous identification of a Ceratocystis species, C. manginecans, which contained two
different internally transcribed spacer sequence types within the ribosomal rRNA cistron,
enabled a study of concerted evolution in this fungus. Using this non-model organism we
were able to show empirical evidence for unequal crossing over and gene conversion as the
ultimate forces acting on this gene region dictating a concerted evolutionary effect. We
suggest that this process is true for all eukaryotes. Using the knowledge drawn from
previously characterized and annotated mitochondrial genomes of other eukaryotes, the
genomes of three Ceratocystis species, namely Ceratocystis fimbriata, Ceratocystis
albifundus and Ceratocystis moniliformis were fully assembled and annotated for
comparative analysis. This comparative study addressed the genome size, gene content,
tRNA presence as well as intron types and their homing endonucleases found among these
three mitochondrial genomes. An interspecies characterization was then undertaken using the
mitochondrial genomes of six different C. albifundus isolates from different geographical
locations in Africa. Genetic variation and similarities among these isolates supports the
previous hypothesis that the origin of this fungus is Southern Africa. It is hoped that the
research presented in this thesis will contribute to the improved understanding of the mitochondrial genomes in Ceratocystis species. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Genetics / Unrestricted
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Control of oak wilt and the genetic structure of Ceratocystis fagacearumPeacock, Kelly L. January 2008 (has links)
Thesis (PH. D.)--Michigan State University. Plant Pathology, 2008. / Title from PDF t.p. (viewed on Sept. 8, 2009) Includes bibliographical references. Also issued in print.
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