A cDNA sequence representing a <i> Brassica carinata</i> gene the expression of which is induced by copper chloride treatment, was isolated from a library constructed with mRNA from treated leaves, and designated CIL1 (COPPER CHLORIDE INDUCED in LEAVES). A Basic Local Alignment Search Tool search revealed that CIL1 has similarities to an auxin-induced gene, AIR12 from <i>Arabidopsis thaliana</i>. Southern blot analysis of CIL1 in <i>B. carinata, B. nigra</i> and <i>B. oleracea</i> indicated that it is a member of a small multigene family. Antisense CIL1 transgenic plants were generated to investigate the function of CIL1, and the resulting transformants displayed increased secondary branching suggesting that CIL1 has a role in regulating hormone content or plant architecture. Results of induction studies indicate that the auxin analog a-naphthalene acetic acid, the cytokinin 6-benzylaminopurine, and +/- abscisic acid increase expression of CIL1. Seven CIL1 antisense lines were grown to the T4 generation and were confirmed homozygous. Analysis of CIL1 expression using real-time quantitative RT-PCR showed reduced expression in every examined line. Transgenic plants produced many leaves at the lateral meristems indicating a release of apical dominance. Additionally, the concentrations of auxins, cytokinins, and abscisic acid were altered in the roots and stems of transgenic plants compared to non-transformed plants. Therefore, CIL1 has a role in regulating hormone content that affects lateral meristem activity, apical dominance, and leaf production.

A cDNA sequence representing a <i> Brassica carinata</i> gene the expression of which is induced by copper chloride treatment, was isolated from a library constructed with mRNA from treated leaves, and designated CIL1 (COPPER CHLORIDE INDUCED in LEAVES). A Basic Local Alignment Search Tool search revealed that CIL1 has similarities to an auxin-induced gene, AIR12 from <i>Arabidopsis thaliana</i>. Southern blot analysis of CIL1 in <i>B. carinata, B. nigra</i> and <i>B. oleracea</i> indicated that it is a member of a small multigene family. Antisense CIL1 transgenic plants were generated to investigate the function of CIL1, and the resulting transformants displayed increased secondary branching suggesting that CIL1 has a role in regulating hormone content or plant architecture. Results of induction studies indicate that the auxin analog a-naphthalene acetic acid, the cytokinin 6-benzylaminopurine, and +/- abscisic acid increase expression of CIL1. Seven CIL1 antisense lines were grown to the T4 generation and were confirmed homozygous. Analysis of CIL1 expression using real-time quantitative RT-PCR showed reduced expression in every examined line. Transgenic plants produced many leaves at the lateral meristems indicating a release of apical dominance. Additionally, the concentrations of auxins, cytokinins, and abscisic acid were altered in the roots and stems of transgenic plants compared to non-transformed plants. Therefore, CIL1 has a role in regulating hormone content that affects lateral meristem activity, apical dominance, and leaf production.

Verticillium dahliae Kleb. causes Verticillium wilt in potato (Solanum tuberosum L.). Hormone signaling pathways are known to play a role in plant defense reactions. A gene expression analysis was performed on a susceptible and a moderately resistant (MR) cultivar of potato after inoculation with either a highly aggressive (HA) or a weakly aggressive (WA) isolate of V. dahliae. Genes related to the salicylic acid (SA), jasmonic acid/ethylene (JA/ET), and abscisic acid (ABA) pathways showed higher expression in the MR cultivar than the susceptible cultivar indicating that they may contribute to resistance. Additionally, a number of genes showed a delayed reaction in the susceptible cultivar and only in plants inoculated with the HA isolate of the pathogen. This trend was observed in genes related to the SA and JA/ET pathways. Overall, this research indicates that more than one hormone signaling pathway may contribute to the defense against V. dahliae by potato.

No description available.

Verticillium dahliae Kleb. causes Verticillium wilt in potato (Solanum tuberosum L.). Hormone signaling pathways are known to play a role in plant defense reactions. A gene expression analysis was performed on a susceptible and a moderately resistant (MR) cultivar of potato after inoculation with either a highly aggressive (HA) or a weakly aggressive (WA) isolate of V. dahliae. Genes related to the salicylic acid (SA), jasmonic acid/ethylene (JA/ET), and abscisic acid (ABA) pathways showed higher expression in the MR cultivar than the susceptible cultivar indicating that they may contribute to resistance. Additionally, a number of genes showed a delayed reaction in the susceptible cultivar and only in plants inoculated with the HA isolate of the pathogen. This trend was observed in genes related to the SA and JA/ET pathways. Overall, this research indicates that more than one hormone signaling pathway may contribute to the defense against V. dahliae by potato.

Développement racinaire du peuplier en réponse aux signaux fongiques lors de la mise en place de l'ectomycorhize Résumé français : L'interaction précoce entre les racines des arbres et les champignons ectomycorhiziens (CEM) est accompagnée d'une forte stimulation du développement de racines latérales (RLs) de la plante hôte. L'objectif de cette thèse est de décrypter les mécanismes moléculaires impliqués dans le développement des RLs de Populus tremula x Populus alba (espèce mycorhizienne) et d'Arabidopsis thaliana (espèce non-mycorhizienne) en réponse au champignon ectomycorhizien Laccaria bicolor. L'auxine étant considérée comme un élément clef de la régulation du développement des RLs, nous avons focalisé notre étude sur les protéines impliquées dans le transport et la signalisation de cette hormone. Nos résultats moléculaires (NimbleGen microarray, RT-PCR quantitative) illustrent que la présence du champignon altère le gradient auxinique dans les racines via une modification de l'expression de PtaPIN9 (AtPIN2), impliqué dans le transport polarisé de l'auxine. Des analyses de plantes mutantes ont suggéré que la stimulation des RLs lors du contact plante/champignon dépend de ce transporteur ainsi que de la signalisation auxinique dans les racines. Notre étude a été élargie à la recherche de molécules émises par le champignon qui interféraient avec les voies auxiniques de la plante. Nos résultats révèlent l'implication des voies de l'éthylène, des jasmonates, des brassinostéroides et des ROS (Reactive Oxygen Species) pendant l'interaction plante/champignon, suggérant une implication des voies de signalisation dépendantes des stress dans les étapes précoces de l'interaction. Nous proposons que Laccaria bicolor stimulerait le développement des RLs en modifiant la répartition et la signalisation de l'auxine endogène de la racine via les voies de signalisation du stress. / The early phase of the interaction between tree roots and ectomycorrhizal (ECM) fungi is accompanied by a stimulation of lateral root (LR) development. This thesis aims on understanding by which molecular mechanisms the interaction of plant and fungus induces LR stimulation. Therefore the ECM fungus L. bicolor in interaction with one of its mycorrhizal hosts, Populus tremula x Populus alba or with the non-mycorrhizal herbaceous model plant Arabidopsis thaliana was studied. We identified gene networks that regulate LR development during the early signal exchanges between Populus tremula x Populus alba and the ECM fungus Laccaria bicolor. We focussed on auxin transport and signalling pathways, as those are key actors regulating LR development. Experiments with poplar and Arabidopsis transgenic auxin response marker lines revealed that the presence of fungal signalling molecules modified auxin gradients in roots. Using microarray- and quantitative Real-time PCR based transcript profiling of poplar roots we uncovered the accumulation of transcripts of the polar auxin efflux carrier PtaPIN9 as well as of auxin responsive transcription factors. A. thaliana transgenics defective in these targets showed that they are crucial for fungus induced LR stimulation. Finally we identified an involvement of ethylene, jasmonates, brassinosteroids and ROS (Reactive Oxygen Species) signalling during fungal LR induction. These pathways are known to be activated upon stress responses in the plant and to interact with auxin pathways. Together these data show how ECM fungi stimulate LR development in plants by interfering with endogenous auxin-levels, -distribution and -signalling most probably through stress signalling pathways.

Ein funktionelles Tiermodell wie die Maus, mit der Möglichkeit einer Kombination aus Genmanipulation und Techniken der Knochenauswertung, könnte für die Forschung von Knochenerkrankungen wegweisend und von Vorteil sein. Deshalb ist das Ziel dieser Arbeit, das Mausmodell auf die Effizienz und Zuverlässigkeit der Knochenanalyseverfahren hin zu untersuchen. Ferner sollte der Einfluss von Östradiol und von fünf verschiedenen Phytoextrakten auf die Mikroarchitektur und die biomechanische Festigkeit der Knochen analysiert werden. Insgesamt wurden 118 Mäuse ovarektomiert. Die Blockade der Östrogenproduktion führt zu einem negativen Einfluss auf die Knochendichte über die Versuchsdauer von 12 Wochen. Die Tiere wurden in sieben Futtergruppen verteilt: neben der sojafreien Negativ-Kontrollgruppe erhielten die Mäuse Östradiol, sowie die Phytohormone Genistein, Equol, OMC, Resveratrol und Bisphenol A. Die Beurteilung der Wirksamkeiten auf die metaphysären Knochenstrukturen erfolgte anhand radiologischer, biomechanischer und histomorphometrischer Kriterien. Insgesamt erwies sich die Bestimmung der Knochenqualität am Tiermodell „Maus“ als messbar und für wissenschaftliche Zwecke geeignet. In der vorliegenden Arbeit bestätigte Östradiol seine starke osteoanabole Potenz und erzielte die besten Wirksamkeiten für alle Untersuchungsverfahren. Genistein zeigte ähnlich gute Effekte auf die Knochenfestigkeit sowohl bei der biomechanischen als auch bei der morphologischen Analyse, wobei die uterotrope Wirkung deutlich geringer war als bei Östradiol. Equol bewirkte eine gesteigerte Spongiosadichte im pQCT mit einer tendenziellen Verbesserung der Knochenfestigkeit im Bruchversuch. Dagegen waren die Zufütterungen der Testsubstanzen Resveratrol, OMC und Bisphenol A der osteoporotischen Kontrollgruppe am ähnlichsten und zeigten keine signifikanten Unterschiede in Bezug auf eine verbesserte Knochenqualität. Zukünftig ist in weiterführenden Untersuchungen zu prüfen, ob die positiven Effekte von Genistein und Equol auch beim Menschen zu den gewünschten Effekten am Knochen führen. Für den therapeutischen Einsatz von Phytohormonen und zur Risikoabschätzung potentieller Nebenwirkungen sind weiterführende Studien notwendig.

No description available.

Orientador: Luciana Francisco Fleuri / Resumo: O Eucalyptus é um importante gênero florestal plantado mundialmente para fins comerciais. O Brasil é líder global em produtividade de Eucalyptus, devido às condições climáticas favoráveis e a eficientes programas de melhoramento baseados em plantações clonais, porém alguns clones de Eucalyptus possuem dificuldades de propagação, principalmente relacionadas ao enraizamento. A inoculação fúngica e bacteriana pode auxiliar o enraizamento e desenvolvimento vegetal pela produção de metabólitos tais como ácido indol-3-acético (AIA) e fitases. O objetivo deste trabalho foi produzir AIA e fitases por fermentação em estado sólido (FES) utilizando Aspergillus spp., Trichoderma spp. e Bacillus spp. e a inoculação das cepas de maior produtividade em mudas de Eucalyptus grandis x E. urophylla (clone IPB2) visando otimizar o desenvolvimento vegetal. A FES ocorreu utilizando bagaço de mandioca, farelos de soja e trigo e grãos secos de destilaria com solúveis (DDGS) de sorgo e milho como substratos. Nos filtrados da FES foram determinados a concentração de AIA e a atividade de fitase. As características físicas e químicas dos substratos [macroporosidade (%), microporosidade (%), retenção de água (mL/cm3), condutividade elétrica (mS/cm3), pH, proteína bruta (%), lipídeos (%), hemicelulose (%), celulose (%) e lignina (%)] foram determinadas e correlacionadas à produtividade das biomoléculas, a fim de esclarecer a influência na alteração do metabolismo microbiano para maior ou menor produtivida... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Eucalyptus is an important forest genus planted worldwide for commercial purposes. Brazil is the global leader in Eucalyptus productivity due to favorable climatic conditions and efficient breeding programs based on clonal plantations, but some Eucalyptus clones have difficulties of propagation, mainly related to rooting. Fungal and bacterial inoculation can positively influence rooting and plant development by producing metabolites such as indole-3-acetic acid (IAA) and phytases. This work aimed to produce IAA and phytases under solid state fermentation (SSF) using Aspergillus spp., Trichoderma spp. and Bacillus spp. and inoculate the best producers in cuttings of Eucalyptus grandis x E. urophylla (clone IPB2), aiming to optimize plant development. The SSF technique was performed using cassava bagasse, soybean and wheat bran and distillers dried grains with solubles (DDGS) of sorghum and maize as substrates. The concentration of IAA and phytase activity were determined in SSF filtrates. The physical and chemical characteristics of the substrates [macroporosity (%), microporosity (%), water retention (mL/cm3 ), electrical conductivity (mS/cm3 ), pH, brute protein (%), lipids (%), hemicellulose %), cellulose (%) and lignin (%)] were determined and correlated to the biomolecules productivity in order to clarify their influence on the alteration of microbial metabolism for higher or lower productivity of IAA and phytases. The microorganisms with higher productivity of IAA and ph... (Complete abstract click electronic access below) / Doutor

Abiotic stresses such as salt stress are the major limiting factors for agricultural productivity, and cause global food insecurity. It is well known that plant associated beneficial microorganisms can stimulate plant growth and enhance resistance to abiotic stresses. In this context, bacterial endophytes are a group of bacteria that colonize the host plant and play a fundamental role in plant growth enhancement under stress condition. Recently, our group reported that the beneficial bacteria Enterobacter sp.SA187 induces plant growth in Arabidopsis under salt stress conditions by manipulation of the plant ethylene signaling pathway. We therefore compared inoculation of plants by SA187 with virulent and non-virulent strains Pst DC3000. Although both strains inhibit plant growth at ambient conditions, Pst DC3000 hrcC-, but not Pst DC3000, induced salt stress tolerance, suggesting that Pst DC3000 hrcC- also contains plant growth promoting activity under stress conditions. Our results indicate that Pst DC3000 hrcC- shares features with beneficial bacteria by inducing salt tolerance through reduction of the shoot and root Na+/K+ ratio. To further elucidate the underlying mechanisms of this interaction with Arabidopsis, RNAseq, hormone and biochemical analyses were performed. Genetic studies also show that Pst DC3000 hrcC- induced salt stress tolerance involving several phytohormone pathways, including auxin, ethylene and salicylic acid. Transcriptome and genetic analyses indicate that glucosinolates play an important role in this beneficial interaction. We found that indolic and alkyl glucosinolates act as negative factors on Pst DC3000 hrcC-, alkyl glucosinolates are positive and indolic glucosinolates negative regulators in SA187 interaction with Arabidopsis. These results reveal that besides a repertoire of effectors, Pst DC3000 hrcC- also produces factors that can be beneficial for plant growth under certain stress conditions, as observed with Enterobacter sp. SA187.