Dans les écosystèmes forestiers, la décomposition du bois est un processus majeur, notamment impliqué dans le cycle du carbone et des nutriments. Les champignons basidiomycètes saprotrophes, incluant les pourritures blanches, sont les principaux agents de cette décomposition dans les forêts tempérées. Bien que peu étudiées, des communautés bactériennes sont également présentes dans le bois en décomposition et cohabitent avec ces communautés fongiques. L'impact des interactions bactéries-champignons sur le fonctionnement d'une niche écologique a été décrit dans de nombreux environnements. Cependant, leur rôle dans le processus de décomposition du bois n'a été que très peu investigué. A partir d'expériences en microcosme et en utilisant une approche non cultivable, il a été démontré que la présence du champignon Phanerochaete chrysosporium influençait significativement la structure et la diversité des communautés bactériennes associées au processus de décomposition du hêtre (Fagus sylvatica). Par une approche cultivable, cet effet mycosphère a été confirmé, se traduisant par une augmentation de la densité des communautés bactériennes en présence du champignon ainsi que par une modification de la diversité fonctionnelle de ces communautés. Enfin, une approche polyphasique a été développée, combinant l'analyse des propriétés physico-chimiques du bois et des activités enzymatiques extracellulaires. Les résultats de cette expérience ont révélé que l'association de P. chrysosporium avec une communauté bactérienne issue de la mycosphère de ce dernier aboutissait à une dégradation plus importante du matériau bois par rapport à la dégradation par le champignon seul, démontrant pour la première fois des interactions bactéries-champignons synergiques dans le bois en décomposition / Wood decomposition is an important process in forest ecosystems in terms of their carbon and nutrient cycles. In temperate forests, saprotrophic basidiomycetes such as white-rot fungi are the main wood decomposers. While they have been less studied, bacterial communities also colonise decaying wood and coexist with these fungal communities. Although the impact of bacterial-fungal interactions on niche functioning has been highlighted in a wide range of environments, little is known about their role in wood decay. Based on microcosm experiments and using a culture-independent approach, we showed that the presence of the white-rot fungus Phanerochaete chrysosporium significantly modified the structure and diversity of the bacterial communities associated with the degradation of beech wood (Fagus sylvatica). Using a culture-dependent approach, it was confirmed that in the presence of the fungus the mycosphere effect resulted in increased bacterial abundance and modified the functional diversity of the fungal-associated bacterial communities. Lastly, a polyphasic approach simultaneously analysing wood physicochemical properties and extracellular enzyme activities was developed. This approach revealed that P. chrysosporium associated with a bacterial community isolated from its mycosphere was more efficient in degrading wood compared to the fungus on its own, highlighting for the first time synergistic bacterial-fungal interactions in decaying wood

Leaky buildings are those that show elevated moisture contents of the framing timber, which can subsequently lead to the establishment of fungal and bacterial decay. Prior to this study, the causative agents of the decay in these leaky buildings were unknown, though it was suspected to be one or more species of decay fungi. Therefore, the overall goal of this multi-disciplinary PhD thesis research was to determine the causative agents of decay in leaky buildings of New Zealand in an effort to develop solutions for both their remediation and future prevention. Use of molecular biology methodology and classical mycological techniques based on morphology enabled identification of decay fungi from framing timber and air samples of leaky New Zealand buildings and provided insight into relative importance based on isolation frequency. In most cases, fungi colonising Pinus radiata D. Don were isolated to produce pure cultures. Mycelia from these cultures on agar media were collected to extract DNA. To identify the fungi to the species level, polymerase chain reaction (PCR) with fungal specific DNA primer pairs were performed followed by DNA sequencing of the internal transcribed spacer (ITS) region. Identification was by BLAST (Basic Local Alignment Search Tool) search on sequences in known GenBanks. In total, 421 samples from leaky buildings were processed, predominately untreated P. radiata decayed framing timber and also fibre cement boards and building paper. From these, sixty-eight fungal identifications were made. The only taxa that were isolated with significant frequency were identified as 4 basidiomycete species, as follows, along with the number of times they were isolated from the 421 samples: • Gloeophyllum sepiarium (Wulf.: Fr.) Karst. 13x • Oligoporus placenta (Fries 1865) Gilb. In Ryv.1985 11x • Antrodia sinuosa (Fr.) Karst. 8x • Gloeophyllum trabeum (Fr.) Murr. 4x Although these species were identified repeatedly, in total they represent less than 10% of the total samples and, therefore, it is concluded that the leaky building decay samples represent high fungal biodiversity. An aerial spore study of internal air, wall cavity air and exterior air of leaky buildings was carried out using a Merck MAS-100 instrument which collects spores directly onto selective media plates. Viable fungal aerial spores were detected at every sampling location tested at the leaky buildings, by the criteria of culturing, with a highest mean of 3714 colony-forming units (CFU) per cubic metre found in the cavities of water-damaged walls. This aerial spore study in conjunction with isolation from decayed wood samples from the same leaky buildings enabled identification of G. sepiarium and A. sinuosa at the same test site. The use of carboxymethylcellulose medium further demonstrated the presence of potential cellulose-degrading fungi within and around the location. Overall, the combination of direct sampling of timber and air sampling proved useful for detection of fungal species variability at a multi-unit building. Four decay fungi isolated from New Zealand leaky buildings and two standard control decay fungi (Coniophora puteana and Serpula lacrymans) were submitted to laboratory wood block testing to determine the effectiveness of currently used wood framing preservatives under laboratory conditions before and after a standard leaching regime. P. radiata blocks were treated with water based boron copper azole and solvent based IPBC propiconazole plus tebuconazole (1:1) preservatives and exposed to the basidiomycetes for 12 weeks. Mass loss for the fungal decay-infected samples was recorded of up to 55% for preservative-treated samples, up to 62% mass loss for leached samples and up to 58% mass loss for un-preservative treated samples. Additionally, well defined dosage responses and approximate toxic thresholds were obtained for all preservatives tested. Results suggested that the minimum IPBC retention specified by Hazard Class 1.2 of NZS3640:2003 (0.025% m/m) is on the low side, and demonstrated after the 2 week leaching regime complete loss of efficacy of boron at 0.4% m/m boric acid equivalent (BAE). This PhD research gave a first overview of fungi occurring in New Zealand leaky buildings, and it demonstrated the following key aspects of wood preservation: 1. The isolated test fungus Antrodia sinuosa was more difficult to control with propiconazole plus tebuconazole at retention 0.007% m/m than the known tolerant fungus Oligoporus placenta; 2. Boron at Hazard Class 1.2 retention of 0.4% m/m BAE was not toxic to Oligoporus placenta; 3. Serpula lacrymans exhibited tolerance to the highest retention of 0.06 %m/m tebuconazole plus propiconazole; and 4. Gloeophyllum species appeared susceptible to all wood preservatives. In order to correlate fungal colonisation and wood decay, colonised wood blocks were studied using light microscopy (LM) and field- emission scanning electron microscopy (FE-SEM). Microscopic observations of P. radiata wood blocks following a standard wood decay test of twelve weeks of fungal colonisation by Serpula lacrymans, Antrodia sinuosa, Oligoporus placenta and Gloeophyllum sepiarium revealed that the two microscopic techniques employed were complementary by allowing features such as pit membranes, chlamydospores or S3/S2 compound middle lamella interface to be photographed in greater detail, allowing for more precise analyses and interpretation of key findings, as follows: 1. Brown rot fungi directly target their apical growth towards degraded pit apetures; 2. Reliance on light microscopy and observed birefringence as a tool to record changes in cell wall crystallinity associated with brown rot decay alone could be misleading; 3. Presence of fine (≤ 1 m) to wide (≥ 3.5 m) bore-hole and hyphal size ranges, and nearly unchanged cell wall thickness of all wood/test fungal combinations, confirmed active decay at moderate to late stages; 4. Some ray parenchyma cells for Antrodia sinuosa, Oligoporus placenta and Gloeophyllum sepiarium colonised blocks were intact throughout late stages of decay, outlining that they were not preferentially degraded early in the brown rot decay process, and 5. Presence of bore-holes, clamp and medallion clamp formation and resting spores (chlamydospores and arthrospores) are fungal specific, can aid in their differentiation and identification, and should be recorded during wood decay studies, as especially resting spores are an important factor when planning remediation strategies. In summary, this PhD thesis research provided the first comprehensive investigation into the biodiversity of fungi from leaky New Zealand buildings, identified the dominant species and presented details about their micromorphology and their decay patterns. It also demonstrated substantial differences in efficacy of preservative formulations currently (December 2008) approved for framing treatments in New Zealand and possible deficiencies where framing may be subjected to severe leaching. This study also provided the first comparative analyses of viable fungal aerial spores between leaky wall cavities and the surrounding air environment. Subsequently, this research added to the knowledge of the decay fungal species diversity in and around New Zealand leaky buildings, outlined their capabilities to degrade treated and un-treated P. radiata framing timber and illustrated the efficacy of New Zealand approved wood preservatives for their potential as remedial treatment and future prevention.

<p><strong>Bakgrund och problemdiskussion:</strong> ROT-avdraget står för Reparation och underhåll, Ombyggnad och Tillbyggnad och är en skattereduktion för privatpersoner på upp till 50 % av arbetskostnaden. Systemet har funnits i flera omgångar och det har skett en del förändringar. Den 1 juli 2009 infördes fakturamodellen vilken innebär att privatpersoner får skattelättnaden direkt vid köpet av tjänsten, det vill säga, kunden betalar endast hälften av arbetskostnaden till säljaren. Därefter får säljaren själv begära resterande belopp från Skatteverket. Fakturamodellen och dess system har varit ett hett diskussionsämne under den senaste tiden om huruvida den påverkar samhällsaktörer positivt eller negativt. Det har från småföretagens sida lyfts fram flera risker och problem med de nya reglerna.</p><p><strong>Syfte:</strong> Syftet med uppsatsen är att undersöka hur fakturamodellen och dess system uppfattas av småföretag. Syftet är också att ta reda på hur småföretag uppfattar att fakturamodellen förhåller sig till regeringens målsättning om att minska den administrativa bördan för mindre företag samt hur modellen går i linje med ROT-avdragets syfte att minska svartarbetet och öka efterfrågan inom byggsektorn.</p><p><strong>Metod:</strong> Denna uppsats bygger på en kvalitativ metod där intervjuer varit det centrala. Av totalt sju genomförda intervjuer har fem gjorts med småföretag inom byggbranschen. En intervju har genomförts med en redovisningskonsult samt en intervju med en rättslig expert på Skatteverket.</p><p><strong>Resultat: </strong>Studiens resultat tyder på att småföretagens administrativa börda har ökat avsevärt sedan fakturamodellens införande. Dessutom påverkas olika näringsgrenar olika mycket av modellen. Regerings syfte med ROT-avdraget gynnas av fakturamodellen då svartarbetet minskat och efterfrågan av tjänster har ökat. Införandet av fakturamodellen kunde dock ha gjorts bättre och studien tyder på att informationen har varit bristfällig.</p> / <p><strong>Background and problem discussion:</strong> For the purpose of this study, “ROT-avdrag” is translated into Renovation deduction. It is a tax reduction for individuals of up to 50 % of the cost of labour for repair and maintenance, and renovation and expansion costs. This system has been in use at several occasions, undergoing some changes. The new invoice system was introduced 1st of July 2009 which means that the customer deducts the tax at the point of purchase of the service. In other words, the costumer will only pay half the cost of labour to the seller. Consequently, it is now the seller who is required to request the outstanding sum straight from the Tax Office. The new model and its system has been a hot topic of whether it affects societal actors positively or negatively. Small businesses have highlighted several risks and problems with the new rules.</p><p><strong>Aim: </strong>The aim of this study is to examine how the invoice system is perceived by small businesses. It also aims to find out how small businesses perceive that the invoice system relates to the Government’s target of reducing the administrative burden on small businesses, and also to see how the invoice system complies with the target of the Renovation deduction, which is to reduce illegal employment and increase demand in the construction sector.</p><p><strong>Method:</strong> This essay is based on a qualitative approach in which interviews have been a central part. Of a total of seven completed interviews, five have been made with small businesses in the construction industry. One interview has been conducted with an accounting consultant and one interview with a legal expert from the Tax Office.</p><p><strong>Results: </strong>The result indicates that small businesses´ administrative burden has increased substantially since the invoice system was introduced. Furthermore, different industries are differently affected by the system. The Government´s target with the Renovation deduction has been benefited by the invoice system sinces illegal employment has been reduced and demand for services has increased. The introduction of the invoice system, however, could have been better; the study indicates that the information have been inadequate.</p>

Bakgrund och problemdiskussion: ROT-avdraget står för Reparation och underhåll, Ombyggnad och Tillbyggnad och är en skattereduktion för privatpersoner på upp till 50 % av arbetskostnaden. Systemet har funnits i flera omgångar och det har skett en del förändringar. Den 1 juli 2009 infördes fakturamodellen vilken innebär att privatpersoner får skattelättnaden direkt vid köpet av tjänsten, det vill säga, kunden betalar endast hälften av arbetskostnaden till säljaren. Därefter får säljaren själv begära resterande belopp från Skatteverket. Fakturamodellen och dess system har varit ett hett diskussionsämne under den senaste tiden om huruvida den påverkar samhällsaktörer positivt eller negativt. Det har från småföretagens sida lyfts fram flera risker och problem med de nya reglerna. Syfte: Syftet med uppsatsen är att undersöka hur fakturamodellen och dess system uppfattas av småföretag. Syftet är också att ta reda på hur småföretag uppfattar att fakturamodellen förhåller sig till regeringens målsättning om att minska den administrativa bördan för mindre företag samt hur modellen går i linje med ROT-avdragets syfte att minska svartarbetet och öka efterfrågan inom byggsektorn. Metod: Denna uppsats bygger på en kvalitativ metod där intervjuer varit det centrala. Av totalt sju genomförda intervjuer har fem gjorts med småföretag inom byggbranschen. En intervju har genomförts med en redovisningskonsult samt en intervju med en rättslig expert på Skatteverket. Resultat: Studiens resultat tyder på att småföretagens administrativa börda har ökat avsevärt sedan fakturamodellens införande. Dessutom påverkas olika näringsgrenar olika mycket av modellen. Regerings syfte med ROT-avdraget gynnas av fakturamodellen då svartarbetet minskat och efterfrågan av tjänster har ökat. Införandet av fakturamodellen kunde dock ha gjorts bättre och studien tyder på att informationen har varit bristfällig. / Background and problem discussion: For the purpose of this study, “ROT-avdrag” is translated into Renovation deduction. It is a tax reduction for individuals of up to 50 % of the cost of labour for repair and maintenance, and renovation and expansion costs. This system has been in use at several occasions, undergoing some changes. The new invoice system was introduced 1st of July 2009 which means that the customer deducts the tax at the point of purchase of the service. In other words, the costumer will only pay half the cost of labour to the seller. Consequently, it is now the seller who is required to request the outstanding sum straight from the Tax Office. The new model and its system has been a hot topic of whether it affects societal actors positively or negatively. Small businesses have highlighted several risks and problems with the new rules. Aim: The aim of this study is to examine how the invoice system is perceived by small businesses. It also aims to find out how small businesses perceive that the invoice system relates to the Government’s target of reducing the administrative burden on small businesses, and also to see how the invoice system complies with the target of the Renovation deduction, which is to reduce illegal employment and increase demand in the construction sector. Method: This essay is based on a qualitative approach in which interviews have been a central part. Of a total of seven completed interviews, five have been made with small businesses in the construction industry. One interview has been conducted with an accounting consultant and one interview with a legal expert from the Tax Office. Results: The result indicates that small businesses´ administrative burden has increased substantially since the invoice system was introduced. Furthermore, different industries are differently affected by the system. The Government´s target with the Renovation deduction has been benefited by the invoice system sinces illegal employment has been reduced and demand for services has increased. The introduction of the invoice system, however, could have been better; the study indicates that the information have been inadequate.

Im Rahmen der vorliegenden Arbeit sollten anhand eines zweifaktoriellen Feldversuchs bestehend aus den Faktoren Fruchtfolge und Pflanzenschutz die Potenziale zur Reduktion von fruchtfolgebedingten Halmbasis- und Wurzelkrankheitserregern an Weizen (Triticum aestivum L.) durch eine geschickte Kombination von Energiefrüchten aufgezeigt werden. Ein Schwerpunkt lag hierbei auf Halmbasisfusarium und die Ausbreitung des Mykotoxins Deoxynivalenols (DON) von der Halmbasis bis in die Ähre. Hierzu wurden vier Fruchtfolgen mit einer unterschiedlichen Dichte an Ackerkulturen etabliert: (1) Maisdaueranbau, (2) Raps – Winterweizen, (3) Raps – Grünroggen/Mais – Winterweizen und (4) Raps – Winterweizen – Grünroggen/Mais – Winterweizen. Der Versuch wurde auf Versuchsflächen der Universitäten Göttingen und Rostock äquivalent angelegt. Die Erhebungen erfolgten in den Jahren 2010 und 2011. Die Bedeutung der halmbürtigen Mykotoxine für die Belastung des Korns wurde in ergänzenden Untersuchungen unter kontrollierten Bedingungen untersucht. Durch eine visuelle Befallsbonitur im Entwicklungsstadium (ES) der späten Milchreife (ES 77) erfolgte die Ermittlung der Befallshäufigkeit von Rhizoctonia cerealis, Oculimacula yallundae/acuformis, Fusarium spp. und Gaeumannomyces graminis var. tritici an der Halmbasis bzw. Wurzel von Weizen. Mykotoxinnachweise (ELISA-Test) des Leittoxins Deoxynivalenol (DON) und DNA-Quantifizierungen (qPCR) von toxinproduzierenden Fusariumarten in Pflanzen aus Feld-, Gewächshaus- und Klimakammerversuchen gaben weiterhin Aufschluss über die Mykotoxinbelastung der Pflanze und systemische Verlagerung von DON nach einem Befall der Halmbasis von Winterweizen mit Fusarium culmorum und F. graminearum. R. cerealis hatte mit einer Befallshäufigkeit von unter 0,5% in beiden Untersuchungsjahren 2010 und 2011 kaum eine Bedeutung. Erhöhte Befallshäufigkeiten konnten für G. graminis var. tritici mit ca. 20% im Jahr 2010 am Standort in Göttingen und 2011 am Standort in Rostock festgestellt werden. Die Befallswerte waren mit <5 sehr niedrig. Für O. yallundae/acuformis konnten leicht erhöhte Befallshäufigkeiten von maximal 25% bzw. 37% an den Standorten in Rostock und Göttingen im Jahr 2010 festgestellt werden. Im letzten Untersuchungsjahr waren die Befallshäufigkeiten mit 7% bzw. 15% an den Standorten Göttingen und Rostock auf einem niedrigen Niveau. Die zweijährigen Erhebungen in den Jahren 2010 und 2011 machten deutlich, dass Fusarium spp. der dominierende Erreger mit 28% am Standort in Göttingen und 63% am Standort in Rostock an der Halmbasis im Mittel der Jahre war. Es zeigte sich für das Abschlussjahr 2011, dass nach dem Jahreseffekt die Fruchtfolge (18% am Standort in Göttingen) bzw. die Interaktion aus Fruchtfolge und Jahreseffekt (19% am Standort in Rostock) den größten Einfluss auf die Befallshäufigkeit von Fusarium spp. hatte. Die Bewertung der Fruchtfolgen erfolgte anhand der Befallshäufigkeiten von O. yallundae/acuformis und Fusarium spp., die am häufigsten in dieser Untersuchung auftraten. Der Vergleich fand auf Grundlage der Befallshäufigkeiten in der Variante ohne Fungizidapplikation statt und wurde mit denen der Variante mit dem situationsbezogenen Pflanzenschutz verglichen. Es konnte festgestellt werden, dass bei beiden Krankheiten die kurze Fruchtfolge 2 (Raps-Weizen) die höchsten Befallshäufigkeiten aufwies. Eine Fungizidapplikation führte häufig zu einer Reduktion des Befalls in den einzelnen Fruchtfolgen, was aber nicht immer statistisch absicherbar war. Am stärksten reduzierten sich die Befallshäufigkeiten, wenn die Fruchtfolgen aufgelockert wurden. Durch die Eingliederung einer Maiskultur in Kombination mit einer Zwischenfrucht wurde die enge Raps-Weizen Folge unterbrochen, wie es in Fruchtfolge 3 (Raps-Zwischenfrucht/Mais-Weizen) zu erkennen war. Zusätzlich zeigte der unterschiedliche Aussaattermin (früh/spät) in den Anbausystemen einen hochsignifikanten Einfluss (p = 0,000) auf die Befallshäufigkeiten, insbesondere Frühsaaten förderten den Befall. Im Fall von Fusarium spp. zeigte der Vergleich der Fruchtfolgen 2 und 3 eine Reduktion der Befallshäufigkeit um ca. 70% an den Standorten in Göttingen und Rostock. Durch die Fungizidmaßnahme in Fruchtfolge 2 und 3 reduzierte sich der Befall am Standort in Göttingen um weitere 40-50%. Für O. yallundae/acuformis wurde der Unterschied der Fruchtfolgen 2 und 3 noch deutlicher. Die Befallshäufigkeiten reduzierten sich um nahezu 100% an den Standorten in Göttingen und Rostock. Der Vergleich zur Variante mit situationsbezogenem Pflanzenschutz in der Fruchtfolge 2 machte deutlich, dass die Pflanzenschutzmaßnahme den Befall signifikant um 50% reduzierte. Die Belastungen der Kornproben mit dem Mykotoxin DON waren sehr gering, wohingegen die Weizenstoppel der Fruchtfolge 4 in der Variante PS-F0 mit bis zu 6000 µg DON/kg TM kontaminiert war. Proben der Fruchtfolge 3 mit 33% Weizenanteil wiesen mit 2500 µg/kg TM die niedrigsten Gehalte an DON auf. In den Fruchtfolgen 2 und 4 mit 50% Weizenanteil wurden nahezu doppelt so hohe Mengen an DON festgestellt. Im Mittel reduzierte die Fungizidmaßnahme zu ES 31 und 51/55 den DON-Gehalt in der Stoppel signifikant um 50%. Der DON-Nachweis im Substrat der Ganzpflanze von Mais zeigte für den Maisdaueranbau leicht erhöhte Werte von 1800 µg DON/kg TM. Mit abnehmendem Maisanteil in der Fruchtfolge reduzierten sich die DON-Gehalte im Maissubstrat. In Proben der Fruchtfolge 4 mit 25% Maisanteil wurde ein um 80% geringerer DON-Gehalt ermittelt. Die ausgewiesene Grünroggensorte Borfuro wies nach künstlicher Infektion an der Halmbasis mit F. graminearum in Gewächshausversuchen über 4500 µg DON/kg TM in der Ganzpflanze zu ES 73 auf und war damit doppelt hoch mit DON kontaminiert wie eine konventionelle Roggensorte. Dieser signifikante Sortenunterschied wurde durch die Bestimmung pilzlicher DNA in der Halmbasis bestätigt. Durch den Rostocker Aktivitätstest mit hoch DON-belastetem Grünroggen im Mini-Batch Verfahren konnte gezeigt werden, dass DON keine inhibitorische Wirkung auf den Fermentationsprozess hat. Es wurde aber eine 10% geringere Gasausbeute in den Varianten mit kontaminiertem Material festgestellt. Kurze Fruchtfolgen mit Energiepflanzen (Raps–Weizen) führen zu nicht unerheblichen Befallshäufigkeiten von O. yallundae/acuformis und Fusarium spp. an der Halmbasis von Weizen. Eine Kombination der Energiefrüchte Raps, Mais und Weizen in Verbindung mit einem späten Saattermin und wendender Bodenbearbeitung verhindert fast vollständig das Auftreten von O. yallundae/acuformis und reduziert signifikant den Befall mit Fusarium spp. an Weizen. Fruchtfolgen mit einem hohen Anteil von Mais bzw. führen auch zu hohen Gehalten an DON im Ganzpflanzensubtstrat von Mais bzw. in der Halmbasis von Weizen. Zwar hat die Toxinbelastung des Ganzpflanzensubstrats von Mais keine negativen Auswirkungen auf den Gärprozess, aber ist die Gasausbeute reduziert. Es Auswirkungen von Fusariuminfektionen auf die Gärqualität von Mais sollten daher in weiteren Untersuchen näher betrachtet werden.

Les bactéries pectinolytiques des genres Pectobacterium (ancien nom Erwinia carotovora) et Dickeya (ancien nom Erwinia chrysanthemi) sont les agents des maladies de la jambe noire et de la pourriture molle. Ils provoquent des dommages aux cultures et des pertes économiques élevées. Les pertes causées par les bactéries pectinolytiques sont évaluées à environ 2 à 10% du rendement de pommes de terre, en fonction de l'année. En 2009, les pertes en pommes de terre en Europe ont été estimées à 250 millions d'euros. Au cours des dernières années, des souches de Dickeya ont été de plus en plus souvent isolées de plantes malades en Pologne, en France et d'autres pays européens. Le genre Dickeya est un groupe très diversifié, qui, selon la nomenclature actuelle contient sept espèces: D. aquatica, D. chrysanthemi, D. dadantii, D. dianthicola, D. paradisiaca, D. solani et D. zeae. Les résultats récents, obtenus dans différents pays européens, indiquent qu'un nouveau groupe de souches de Dickeya peut infecter efficacement les plantes de pomme de terre et causer des symptômes de la maladie en climat tempéré. Les souches de D. solani sont considérés comme plus agressives que les autres bactéries causant la jambe noire. Une analyse préliminaire a suggéré qu’elles ont besoin de plus faibles températures optimales pour le développement de la maladie ainsi que de niveaux d'inoculum inférieurs pour la propagation de l'infection. Elles semblent avoir une plus forte capacité à coloniser les racines de plantes de pomme de terre et à se propager à travers le système vasculaire de la plante. Les souches de D. solani produisent une large gamme d’enzymes dégradant de la paroi cellulaire végétale, qui sont les principaux facteurs de virulence. Les objectifs de l'étude étaient les suivants: 1) la caractérisation phénotypique et génotypique des souches de D. solani isolées dans des pays ayant des conditions climatiques différentes: Pologne, Finlande et Israël, 2) l'étude de l’influence d'extraits de pomme de terre sur l'expression de quelques gènes sélectionnés de D. solani: pelD, pelL, tssk, lfaA, 3) la génomique comparative de dix souches de D. solani, basée sur 4 génomes séquencés pour cette étude et 6 séquences génomiques disponibles dans la base de données GenBank. En conclusion, toutes les études génomiques ont montré que les souches de D. solani forment un groupe très homogène. Cependant, leur analyse phénotypique révèle une certaine variabilité entre les souches provenant de différentes conditions climatiques. La raison des variations observées dans les traits phénotypiques peut être liée à la régulation de l'expression des gènes codant les facteurs de virulence qui peuvent être influencés par la température, le pH, la carence en fer ou en oxygène et la disponibilité en azote, ainsi que par la présence de composés spécifiques des tissus végétaux. / Dickeya solani is a species consisting of newly emerged plant pathogenic bacteria that cause blackleg and soft rot diseases. They are responsible for great damages to potato plantations in most of European countries. D. solani strains produce a wide range of plant cell-wall degrading enzymes which are the main virulence factors. The aims of the study were: 1) phenotypic and genotypic characterizations of the D. solani strains isolated in countries with different climatic conditions: Poland, Finland and Israel, 2) study of the potato tuber extract influence on the expression of a few selected D. solani genes : pelD, pelL, tssK, lfaA,3) comparative genomics of ten D. solani strains, performed on 4 genomes sequenced for this study and 6 genome sequences available in the GenBank databases. The results showed that the strains from different climatic conditions have identical profiles in rep-PCR (with three different primers) and in Restriction Fragments Lenght Polymorphism-Pulse Field Gel Electrophoresis. However, they do differ phenotypically, especially in the activity of plant cell-wall degrading enzymes. Polish strains have higher activities of pectinolytic, cellulolytic and proteolytic enzymes than Finnish and Israeli strains. D. solani mutants in the pelD, pelL, tssK, lfaA genes were constructed by site-specific mutagenesis. The highest induction by plant extracts was observed for the lfaA gene. The expression of pelL is also induced by plant derived signal(s), but not that of pelD and tssK. Comparative genomics helped to elucidate the D. solani pangenome. The 10 D. solani strains genomes are coding for a total of 41 947 proteins which were grouped into 5 045 Orthologous Groups, 3 809 belonging to the core genome, 413 to the accessory genome and 823 to the unique genome. Some pathogenicity-related genes as well as their regulators were selected on the basis of the knowledge available for D. dadantii 3937, the most studied Dickeya strain, which belongs to a closely related species. Analysis of their protein sequence showed no difference in the sequence of those genes within the 10 genomes. All the genetic studies proved that D. solani strains form a very homogenous group. On the other hand, the phenotypic analysis showed some variability among strains from different climatic conditions. The observed variations in the phenotypic traits can results from a different regulation of the expression of the genes encoding virulence factors which are influenced by temperature, pH, iron deprivation, oxygen and nitrogen availability, as well as by the presence of plant compounds.

Made available in DSpace on 2015-03-26T13:37:48Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1101546 bytes, checksum: 470ffe81811565bb509698fba48cfb51 (MD5) Previous issue date: 2012-02-13 / It was aimed to evaluate the efficiency of semi-selective media, for pathogenicity tests and primers specificity for detection of Xanthomonas campestris pv. campestris (Xcc). For execution of experiments, we used 29 strains received from different regions in Brazil. For confirmation of the identity of the strains we carried out xanthomonadins production test, asparagine utilization, analysis of the 16S rDNA genes region of bacterial genome and pathogenicity tests. Of the 29 strains, 24 were identified as belonging to Xanthomonas genus. None of the strains induced hypersensitivity reaction (HR) in inoculated plants and only 14 strains induced typical symptoms of black rot in collard. The NSCAA medium was the uniquely to support the growth of all strains, whereas mCS20ABN, YTSA-CC and Xan-D media allowed the growth of most of strains. Except of X03 strain, the XCR/XCF and HrcCR2/HrcCF2 primers allowed the amplification and visualization of bands of expected size to Xcc. / Avaliou-se a eficiência de meios de cultura semi-seletivos, de testes de patogenicidade e a especificidade de primers para a detecção de Xanthomonas campestris pv. campestris (Xcc). Para a execução dos experimentos, foram utilizados 29 isolados recebidos de diferentes regiões do Brasil. Para a confirmação da identidade dos isolados foram realizados os testes de produção de xantomonadinas e de utilização de asparagina, análise da região 16s do genoma bacteriano e testes de patogenicidade. Dos 29 isolados, 24 foram identificados como pertencentes ao gênero Xanthomonas. Nenhum dos isolados induziu HR nas plantas inoculadas e apenas 14 isolados induziram sintomas típicos da podridão negra em couve. O meio NSCAA foi o único capaz de suportar o crescimento de todos os isolados, enquanto os meios mCS20ABN, YTSA-CC e Xan-D permitiram o crescimento da maioria dos isolados. À exceção do isolado X03, os primers XCR/XCF e HrcCR2/HrcCF2 permitiram a amplificação e visualização das bandas de tamanhos esperados para Xcc.

Resumo: O brócolis (Brassica oleracea var. italica) é uma espécie exigente em nutrientes, destacando-se os elementos nitrogênio e potássio, que são exigidos em maiores quantidades pelas plantas, podendo influenciar na produção, qualidade e também na severidade de diversas doenças. Com o objetivo de estudar os efeitos desses elementos na severidade da podridão negra, causado por Xanthomonas campestris pv. Campestri (Xcc) e a sua influência na produção de brócolis tipo inflorescência única, foi realizado o experimento no Departamento de Produção Vegetal/Horticultura da FCA/UNESP - Botucatu. O delineamento utilizado foi em parcela subdividida com fatorial na subparcela, em blocos casualisados com quatro repetições. Na parcela avaliou-se a influência da inoculação (plantas não inoculadas e inoculadas com Xcc) e na subparcela avaliou-se o fatorial 4 x 4, doses de potássio (0, 275, 550 e 825 kg ha-1) e nitrogênio (0, 150, 300 e 450 kg ha-1). O híbrido de brócolis utilizado foi o BRO68 (Rogers). A semeadura foi realizada em 18/02/2004 e as plântulas foram transplantadas aos 33 dias após semeadura (DAS) em vasos de dez litros, sob ambiente protegido. Realizou-se a inoculação pelo método de palito (64 DAS) e as colheitas foram realizadas de 28/05/2004 a 12/06/2004 (99 aos 114 DAS). As adubações foram realizadas no plantio, pela incorporação ao solo de 45% da dose de potássio e 10% da dose de nitrogênio de cada tratamento e em cobertura, aplicados via fertirrigação (55% do potássio e 90% do nitrogênio). Foram avaliadas a severidade da Xcc através do PANC (porcentagem da altura necrosada do caule) e porcentagem das folhas retidas nas plantas (FR), produção e diâmetro das cabeças, teores de macronutrientes, no momento da inoculação e na colheita...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Broccoli is one vegetable specie that demand fertilizers, mainly nitrogen and potassium are required in higher quantity, which can have influence in yields, quality and severity level of diseases. Evaluated the influence of nitrogen and potassium fertilizations in black rot (Xanthomonas campestris pv. campestris) severity and broccoli yields, in the Departamento de Produção Vegetal/Horticultura - FCA/UNESP - Botucatu country, São Paulo State, Brazil. The experimental design was split plot with factorial in plot, in randomized blocks with four replicants. In the plot was evaluated the influence of inoculation (plant no inoculated or inoculated with Xcc (Xanthomonas campestris v. campestris) with four replications, considering potassium rates (0, 275, 550 and 825 kg ha-1) and nitrogen rates (0, 150, 300 and 450 kg ha-1). Hybrid BRO 68 (Rogers) was seeded in 18/02/2004 and transplanted in 33 days after seeding (DAS) for pot with 10 liters of capacity in plastic house conditions. The Xcc inoculation was made using "toothpick" methods (64 DAS) and the harvesting occurs in 28/05/2004 to 12/06/2004 (99 to 114 DAS). Incorporated in soil before planting with 45% potassium rate and 10% nitrogen rate of each treatment, and after planting fertilization was in fertirrigation system (55% potassium and 90% nitrogen). The severity of Xcc was evaluated with a PANC (percentage of necrosed height of the stem) method and the percentage of leaf kept in plants, the broccoli yield and the diameter of head, macronutrients ratios, was assessment during inoculations and the harvesting. The results showed that interactions among of three factors did not have significance for neither characteristics, potassium x nitrogen fertilizers interactions was significance to yield, head diameter, and PANC and macronutrients ratios (N, P, K, Ca and Mg)...(Complete abstract click electronic access below) / Orientador: Rumy Goto / Coorientador: Antonio Carlos Maringoni / Banca: Roberto Lyra Villas Bôas / Banca: Marcia de Moraes Echer / Banca: Rômulo Fujito Kobori / Banca: Margarida Fumiko Ito / Doutor

Made available in DSpace on 2014-12-17T14:54:58Z (GMT). No. of bitstreams: 1 DaviBB_DISSERT_1-70.pdf: 4567680 bytes, checksum: 150ff5afc1806ca374278b4c00a1f5a3 (MD5) Previous issue date: 2010-12-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Metamaterials exhibiting negative refraction have attracted a great amount of attention in recent years mostly due to their exquisite electromagnetic properties. These materials are artificial structures that exhibit characteristics not found in nature. It is possible to obtain a metamaterial by combining artificial structures periodically. We investigated the unique properties of Split Ring Resonators, High impedance Surfaces and Frequency Selective Surfaces and composite metamaterials. We have successfully demonstrated the practical use of these structures in antennas and circuits. We experimentally confirmed that composite metamaterial can improve the performance of the structures considered in this thesis, at the frequencies where electromagnetic band gap transmission takes place

This study evaluated the effect of Pratlenchus brachyurus and Fusarium verticillioides, and their relationship, on growth and development of two mayze hybrids (30F80 and 30K73). The experiment was conducted in greenhouse conditions at Pioneer Hi-bred Research Center in Itumbiara, GO, Brazil. The experimental design was randomized blocks with 15 treatments and 10 replications. Treatments included a non-inoculated control; inoculation of Fusarium in the seed and in the soil; three populations levels of Pratylenchus at sowing and at 30 days after planting (50, 100 and 500 nematodes/plot), with and without the inoculation of Fusarium in the soil; and three populations leves of Pratylenchus inoculated 30 days after sowing with Fusarium inoculated in seed at sowing. At plant maturity the following variables were evaluated: plant height and ear length, stalk diameter, root fresh and dry matter, stalk fresh and dry matter, reproduction factor and fusariosis severity on the stalk. Fusarium stalk colonization was evaluated in a scale from 1 to 9. The 30F80 hybrid had lower plant height and ear length, stalk diameter, stalk and root fresh matter when the seeds were inoculated with the suspension of Fusarium and sowing immediately after inoculation. The maize hybrids 30F80 and 30K73, showed the lowest root length, stalk fresh and dry matter, and root fresh and dry matter mainly when the soil was inoculated with Fusarium and sown in the same day, and the inoculation with 500 juveniles and/or adults of Pratylenchus, was done 30 days after sowing. The maize hybrid 30K73 obtained lower plant height and ear length when seeds were inoculated with the suspension of Fusarium and sown in the same day. Maize seeds inoculated with Fusarium verticillioides at planting decreased plant height, ear length, and root and shoot fresh weight on both hybrids. Stalk diameter of 30K73 hybrid and root length of hybrid 30K73 were also reduced. Soil inoculation of Fusarium verticillioides at planting and Pratylenchus brachyurus inoculated 30 days after planting (500 nematodes/plot) decreased root elongation and stalk, and root dry weights on both hybrids. However, plant height was only reduced on 30K73 hybrid. Future research is needed to better understand the relationship between Pratylenchus brachyurus and Fusarium verticillioides on maize growth and development. / O objetivo deste estudo foi avaliar o efeito de Pratylenchus brachyurus e/ou Fusarium verticillioides e sua relação no desenvolvimento de dois híbridos de milho (30F80 e 30K73). O experimento foi conduzido em casa de vegetação no Centro de Pesquisa da Pioneer Sementes de Itumbiara-GO. O delineamento experimental foi inteiramente ao acaso com 15 tratamentos/por híbrido (totalizando 30 tratamentos) e 10 repetições. Os tratamentos foram: testemunha (sem inoculações), inoculação de fungo nas sementes e no solo; inoculação de três populações de nematóide na semeadura e 30 dias após a semeadura (50, 100 e 500 nematóides/vaso), com e sem inoculação do fungo no solo; e três níveis populacionais de nematóides inoculados 30 dias após a semeadura, com o fungo inoculado na semente. Após a maturação (estádio R7), foram avaliadas as características: altura de planta e de espiga, diâmetro de colmo, matéria fresca e seca de raiz, matéria fresca e seca de colmo, fator de reprodução do nematóide e severidade de fusariose no colmo do milho. Observou-se que o híbrido de milho 30F80 obteve uma menor altura de planta e de espiga, diâmetro de colmo, matéria fresca de colmo e de raíz, quando as sementes foram inoculadas com a suspensão de conídios de Fusarium verticillioides e semeadura realizada no mesmo dia dessa inoculação. Os híbridos de milho 30F80 e 30K73 apresentaram o menor comprimento de raiz, matéria fresca e seca de colmo, e matéria fresca e seca de raiz, principalmente quando o solo foi inoculado com Fusarium verticillioides, semeou-se no mesmo dia e a inoculação do nematóide na população de 500 juvenis e/ou adultos de Pratylenchus brachyurus realizada 30 dias após a semeadura. O híbrido de milho 30K73 obteve uma menor altura de planta e de espiga quando as sementes foram inoculadas com a suspensão de conídios de Fusarium verticillioides e semeadura realizada no mesmo dia dessa inoculação. Sementes de milho inoculadas com o fungo na semeadura diminuiram a altura de planta e de espiga e peso fresco de raiz e de parte aérea nos dois híbridos de milho. Diâmetro de colmo no híbrido 30F80 e comprimento de raiz no híbrido 30K73 também foram reduzidos. A inoculação do solo com o fungo na semeadura e nematóide inoculado 30 dias após (500) proporcionou menor comprimento de raiz e peso seco e fresco de raiz e colmo nos dois híbridos. Contudo, altura de planta foi reduzida somente no híbrido 30K73. Outros estudos de interações entre microrganismos, em especial de Pratylenchus brachyurus e Fusarium verticilliodes, deverão ser realizados, a fim de melhor entender o efeito desta combinação no prejuízo das plantas. / Mestre em Agronomia