Pathogenic fungi, such as polypore fungi that infect live sapwood, decrease quality and value of wood; however their effects on canopy physiology and growth have been little examined. This study examines how Fomes fomentarius, a species of polypore fungus affects canopy physiology in Betula alleghaniensis. A mobile canopy lift enabled the collection of leaf physiology, morphology and chemistry data from canopies of infected, damaged, and control trees. A molecular protocol developed to detect and identify polypore fungi in live trees confirmed that F. fomentarius was the major species present in infected trees. Infected trees exhibited reductions in physiological performance and growth, along with higher leaf carbon and chlorosis. While some characteristics of fungal infection were consistent with a mechanism involving partial xylem occlusion, patterns did not resemble those of a simple drought response. Likely, other factors such as fungal toxins or host defense mechanisms also contribute to these patterns.

Pathogenic fungi, such as polypore fungi that infect live sapwood, decrease quality and value of wood; however their effects on canopy physiology and growth have been little examined. This study examines how Fomes fomentarius, a species of polypore fungus affects canopy physiology in Betula alleghaniensis. A mobile canopy lift enabled the collection of leaf physiology, morphology and chemistry data from canopies of infected, damaged, and control trees. A molecular protocol developed to detect and identify polypore fungi in live trees confirmed that F. fomentarius was the major species present in infected trees. Infected trees exhibited reductions in physiological performance and growth, along with higher leaf carbon and chlorosis. While some characteristics of fungal infection were consistent with a mechanism involving partial xylem occlusion, patterns did not resemble those of a simple drought response. Likely, other factors such as fungal toxins or host defense mechanisms also contribute to these patterns.

No description available.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 5 uppsatser.

Data de aprova??o ausente. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-06-08T22:19:37Z No. of bitstreams: 2 luana_martins_santos.pdf: 1170564 bytes, checksum: 215e11cc17c654f8760cc6085cca3464 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-06-22T15:18:34Z (GMT) No. of bitstreams: 2 luana_martins_santos.pdf: 1170564 bytes, checksum: 215e11cc17c654f8760cc6085cca3464 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-06-22T15:18:34Z (GMT). No. of bitstreams: 2 luana_martins_santos.pdf: 1170564 bytes, checksum: 215e11cc17c654f8760cc6085cca3464 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A produ??o de muda ? uma etapa primordial e decisiva para a implanta??o de uma floresta. No entanto, devido a diversos fatores de ordem t?cnica, as perdas no setor de produ??o s?o bastante relevantes. Dentre estes fatores est? o descarte do substrato, que quando feito de forma err?nea favorece a prolifera??o de micro-organismos fitopatog?nicos em viveiro. Isso pode desencadear em perdas significativas e ainda se tornar um passivo ambiental. Raramente o substrato ? reutilizado nos viveiros comerciais, uma vez que presume-se que as caracter?sticas f?sica, qu?mica e biol?gicas formam perdidas durante a produ??o das mudas. Contudo, h? poucos estudos sobre micro-organismos em substratos. A import?ncia deste estudo fundamenta-se na escassez de pesquisa sobre essa problem?tica que afeta o setor de produ??o de mudas, bem como buscar alternativas sustent?veis que pressup?e a demanda de uso desse insumo. A aplica??o de t?cnicas moleculares vem sendo empregadas para detectar e identificar os micro-organismos em diversos ambientes. Neste contexto, o objetivo deste estudo foi detectar a diversidade microbiol?gica em amostras de substratos descartados pela t?cnica de PCR-RFLP. Foram coletados dez amostras de substratos em diferentes viveiros no estado de Minas Gerais em diferentes fases de produ??o e estado de tecnifica??o. O DNA gen?mico total foi extra?do e amplificado pela t?cnica de PCR com oligonucleot?deos espec?ficos para fungos, bact?ria e archaea. Os produtos amplificados foram submetidos ? clivagem com enzimas de restri??o HaeIII, BamHI, TaqI e HindIII, para detec??o de poss?veis polimorfismos entre as amostras por meio da t?cnica de PCR-RFLP. Foi poss?vel verificar diferen?as entre as amostras de substratos, tanto em rela??o ao tamanho da regi?o do DNA amplificada, bem como em rela??o ? presen?a de s?tios de restri??o. Com base no ?ndice de similaridade, detectou-se uma maior varia??o da diversidade dentro da amostra em diferentes fases do que nas amostras entre os diferentes viveiros. Portanto, estes resultados podem ser relevantes para o conhecimento da diversidade microbiol?gica em substrato. Por?m mais estudos se fazem necess?rios para maior compreens?o destes micro-organismos e sua fun??o no substrato. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / The production of changes is a crucial and decisive step for the implementation of a forest. However, due to several technical factors, losses in the production sector are quite relevant. Among these factors is the disposal of substrate, which when done wrongly favors the proliferation of phytopathogenic microorganisms in nursery. This can trigger significant losses and still become a environmental liabilities. Rarely the substrate is reused in commercial nurseries, since it is assumed that the physical, chemical and biological characteristics were lost during the production of seedlings. However, there are few studies on microorganisms on substrates. The importance of this study is based on the scarcity of research on this issue that affects the production of seedlings, as well as seek sustainable alternatives that assumes the use of this raw material demand. The application of molecular techniques have been employed to detect and identify microorganisms in various environments. In this context, the objective of this study was to detect microbiological diversity in substrate samples dropped by PCR-RFLP technique. Ten samples were collected of substrates in different nurseries in the State of Minas Gerais in different stages of production and State of modern farms. Total genomic DNA was extracted and amplified by the PCR technique with specific oligonucleotides to fungi, bacteria and archaea. The amplified products were submitted to cleavage with HaeIII restriction enzymes, BamHI, HindIII, and TaqI for detection of possible polymorphisms between the samples by PCR-RFLP technique. It was possible to check differences between samples of substrates, both in relation to the size of the amplified DNA region as well as in relation to the presence of restriction sites. Based on the index of similarity, if a greater variation of diversity within the sample at different stages than in samples between different nurseries. Therefore, these results may be relevant to the knowledge of microbiological diversity in substrate. However more studies are needed to better understanding of these microorganisms and their role in the substrate.

Orientador: Edson Luiz Furtado / Resumo: A seringueira (Hevea brasiliensis) é a terceira cultura florestal mais plantada no Brasil, e o estado de São Paulo é responsável por mais de 60% da produção de látex do país. É uma espécie nativa da região amazônica que possui hábito caducifólio, e durante o período de reenfolha é suscetível ao ataque de fitopatógenos foliares, que prejudicam e até limitam seu estabelecimento em determinadas regiões. Dentre os principais patógenos foliares da seringueira, destacam-se os fungos causadores de oídios, microrganismos biotróficos que infectam tecidos jovens, e podem causar desfolha, principalmente em condições de viveiro e jardim clonal. O agente causal do oídio da seringueira é descrito como Erysiphe quercicola, porém, devido a insuficientes descrições taxonômicas, morfológicas e moleculares desta doença, seu agente causal permanece em discussão, além da fase sexual deste patógeno carecer de qualquer registro neste hospedeiro. Portanto, o objetivo deste trabalho é caracterizar o oídio da seringueira, utilizando caracterizações morfológicas, análises moleculares e testes de patogenicidade. No período de julho a dezembro de 2019, foram coletadas amostras foliares de seringueira em diferentes estágios fenológicos infectadas com oídio na região de Botucatu, São Paulo. Para a caracterização morfológica, foram registradas e mensuradas características das hifas, conídios e conidióforos, que correspondem à fase assexuada do fungo. A caracterização molecular foi realizada através de análi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Rubber tree (Hevea brasiliensis) is the third most planted forest crop in Brazil, and the state of São Paulo is responsible for more than 60% of the country's latex production. It is a species native to the Amazon region that has a deciduous habit, and during the re-leafing period it is susceptible to the attack of leaf phytopathogens, which harm and even limit its establishment in certain regions. Among the main leaf pathogens of the rubber tree, there are the fungi that cause powdery mildew, biotrophic microorganisms that infect young tissues, and can cause defoliation, especially in nursery and clonal garden conditions. The causal agent of rubber mildew is described as Erysiphe quercicola, however, due to insufficient taxonomic, morphological and molecular descriptions of this disease, its causal agent remains under discussion, in addition to the sexual phase of this pathogen lacking any record in this host. Therefore, the objective of this work is to characterize powdery mildew mildew, using morphological characterizations, molecular analyzes and pathogenicity tests. From July to December 2019, leaf samples of rubber trees were collected at different phenological stages infected with powdery mildew in the Botucatu region, São Paulo. For morphological characterization, characteristics of hyphae, conidia and conidiophores, which correspond to the asexual phase of the fungus, were recorded and measured. Molecular characterization was performed through phylogenetic analyzes o... (Complete abstract click electronic access below) / Mestre

The movement of the exotic and destructive plant pathogen Phytophthora ramorum into unquarantined areas via the plant nursery trade provides a potential outlet for transmission into eastern United States forests. A two-year survey of Phytophthora species in a forest adjacent to an ornamental plant nursery in Mississippi isolated P. ramorum 20 times from water and once from vegetation, with an additional detection of 14 Phytophthora species and one provisional species. Isolates were recovered from soil, water, and vegetation using baiting and filtering techniques, and verified by their DNA through Polymerase Chain Reaction (PCR) followed by genomic sequencing. This study confirms the ability of P. ramorum to sustain itself in Mississippi, although disease progression appears to be inhibited by the relatively small window of favorable environmental conditions.

No description available.

<p>Eastern black walnut (<i>Juglans nigra</i> L.) ranks among the most highly valued timber species in the central hardwood forest and across the world. This valuable tree fills a critical role in native ecosystems as a mast bearing pioneer on mesic sites. Along with other <i>Juglans</i> spp. (Juglandaceae), <i>J. nigra</i> is threatened by thousand cankers disease (TCD), an insect-vectored disease first described in 2009. TCD is caused by the bark beetle <i>Pityophthorus juglandis</i> Blackman (Corthylini) and the phytopathogenic fungus <i>Geosmithia morbida</i> Kol. Free. Ut. & Tiss. (Bionectriaceae). Together, the <i>P. juglandis</i>-<i>G. morbida</i> complex has expanded from its historical range in southwest North America throughout the western United States (U.S.) and Europe. This range expansion has led to widespread mortality among naïve hosts <i>J. nigra</i> and <i>J. regia</i> planted outside their native distributions.</p> <p> The severity of TCD was previously observed to be highest in urban and plantation environments and outside of the host native range. Therefore, the objective of this work was to provide information on biotic and abiotic environmental factors that influence the severity and impact of TCD across the native and non-native range of <i>J. nigra</i> and across different climatic and management regimes. This knowledge would enable a better assessment of the risk posed by TCD and a basis for developing management activities that impart resilience to natural systems. Through a series of greenhouse-, laboratory- and field-based experiments, environmental factors that affect the pathogenicity and/or survival of <i>G. morbida</i> in <i>J. nigra</i> were identified, with a focus on the microbiome, climate, and opportunistic pathogens. A number of potentially important interactions among host, vector, pathogen and the rest of the holobiont of TCD were characterized. The <i>holobiont</i> is defined as the whole multitrophic community of organisms—including <i>J. nigra</i>, microinvertebrates, fungi and bacteria—that interact with one another and with the host.</p> <p>Our findings indicate that interactions among host, vector, pathogen, secondary pathogens, novel microbial communities, and novel abiotic environments modulate the severity of TCD in native, non-native, and managed and unmanaged contexts. Prevailing climatic conditions favor reproduction and spread of <i>G. morbida</i> in the western United States due to the effect of wood moisture content on fungal competition. The microbiome of soils, roots, and stems of trees and seedlings grown outside the host native range harbor distinct, lower-diversity communities of bacteria and fungi compared to the native range, including different communities of beneficial or pathogenic functional groups of fungi. The pathogen <i>G. morbida</i> was also associated with a distinct community of microbes in stems compared to <i>G. morbida</i>-negative trees. The soil microbiome from intensively-managed plantations facilitated positive feedback between <i>G. morbida</i> and a disease-promomting endophytic <i>Fusarium solani</i> species complex sp. in roots of <i>J. nigra</i> seedlings. Finally, the nematode species <i>Bursaphelenchus juglandis</i> associated with <i>P. juglandis</i> synergizes with <i>G. morbida</i> to cause foliar symptoms in seedlings in a shadehouse; conversely, experiments and observations indicated that the nematode species <i>Panagrolaimus</i> sp. and cf. <i>Ektaphelenchus</i> sp. could suppress WTB populations and/or TCD outbreaks.</p> <p>In conclusion, the composition, function, and interactions within the <i>P. juglandis</i> and <i>J. nigra</i> holobiont play important roles in the TCD pathosystem. Managers and conservationists should be aware that novel associations outside the host native range, or in monocultures, intensive nursery production, and urban and low-humidity environments may favor progression of the disease through the effects of associated phytobiomes, nematodes, and climatic conditions on disease etiology. Trees in higher diversity, less intensively managed growing environments within their native range may be more resilient to disease. Moreover, expatriated, susceptible host species (<i>i.e.</i>, <i>J. nigra</i>) growing in environments that are favorable to novel pests or pest complexes (<i>i.e.</i>, the western U.S.) may provide connectivity between emergent forest health threats (<i>i.e.</i>, TCD) and native host populations (<i>i.e.</i>, <i>J. nigra</i> in its native range).</p>