This thesis evaluates an electric vehicle with four independently-controlled in-wheel electric motors. The electric vehicle investigated in this work requires a main con- troller that not only coordinates with each individual motor drive controller, but is also needed to distribute torque and power to each in-wheel motor. The controller adjusts the speed of each motor to the driving conditions according to the require- ments and emulates the behavior of a mechanical di erential. Then, in addition to the electronic di erential controller, a simple yet robust control strategy for maximiz- ing traction force between tire and road is developed and presented. Moreover, the controller continuously senses the yaw rate and prevents over- and under-steering by adjusting the torque on the right or left wheels. Simulation and experimental results validate the proposed strategy.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-05-03T23:20:59Z No. of bitstreams: 1 FAGNER DE ARAUJO PEREIRA – TESE (PPGEE) 2016.pdf: 5563651 bytes, checksum: 359256a68bd0b865ecd15f6e1d7cb585 (MD5) / Made available in DSpace on 2018-05-03T23:20:59Z (GMT). No. of bitstreams: 1 FAGNER DE ARAUJO PEREIRA – TESE (PPGEE) 2016.pdf: 5563651 bytes, checksum: 359256a68bd0b865ecd15f6e1d7cb585 (MD5) Previous issue date: 2016-09-09 / É apresentada uma plataforma implementada com controladores digitais de sinal (DSCs – Digital Signal Controllers) desenvolvida para estudos do comportamento dinâmico em tempo real dos transformadores de corrente com entreferro, utilizados em sistemas de proteção e medição de redes de energia elétrica. Os algoritmos implementados simulam a corrente de defeito em um sistema de energia eléctrica, bem como a resposta transitória do transformador de corrente. Um método para corrigir a distorção da corrente secundária do TC com entreferro é apresentado, onde o fluxo residual é desprezível. Para estimar o fluxo, um enrolamento terciário deve estar disponível. Os erros de fase e de relação, bem como as distorções na corrente secundária devido à saturação do núcleo em situações de falta são adequadamente corrigidos pelo método. Vários casos foram testados e os resultados indicam que o método proposto é eficaz em melhorar o desempenho dos sistemas de protecção com base na medição de corrente. / A platform implemented with Digital Signal Controllers (DSCs) developed for real time studies of the dynamic behavior of the air-gapped current transformers (CTs) used in power grid protection and measurement systems is presented. The implemented algorithms simulate the fault current in an electric power system as well as the transient response of the current transformer. A method for correcting the CT secondary current distortion is presented in the case of gapped core where residual flux is negligible. To estimate the flux, a tertiary winding must be available. The ratio and phase errors, as well as the distortions in secondary current due the core saturation in fault situations are properly corrected by the method. Several cases were tested and the results indicate that the proposed method is very effective in improving the performance of protection schemes based on the current measurement.

Pseudomonas aeruginosa (Pa) est une bactérie multi-résistante responsable de plus de 10% des infections nosocomiales en Europe. Pa réagit aux signaux environnementaux en activant un système de régulation complexe qui permet à la bactérie d’adopter une mode de vie planctonique (infection aigue) ou sessile (infection chronique caractérisée par la formation des biofilms). Le système à deux composants GacS/GacA joue un rôle central dans la permutation entre ces deux modes. Pendant une infection chronique, GacS HK forme des homodimeres permettant l’activation de la formation du biofilm. Nos travaux ont confirmé le rôle du domaine périplasmique de GacS HK (GacSp) dans la détection du signal et l’activation de la voie GacS/GacA. Malgré l’instabilité de GacSp, J’ai résolu la structure 3D de ce domaine par la spectroscopie RMN. GacSp adopte un repliement PDC qui caractérise un grand nombre de domaines senseurs connus pour fixer une large gamme de ligands. L’étude de la structure m’a permis de proposer un site de fixation du ligand. Les résultats présentés dans cette thèse montrent l’importance de GacSp et propose une nouvelle piste pour les études thérapeutiques visant à éradiquer le biofilm.La deuxième partie de ma thèse présente la structure cristalline du glycoside hydrolase 39 du B. cellulosilyticus WH2 présente dans le côlon (GH39wh2). GH39wh2 partage la même architecture avec les autres membres de la famille 39, cependant, elle possède un site actif plus large et plus exposé. Les analyses structurales et bioinformatiques ont permis d’attribuer GH39wh2 à un nouveau sous-groupe caractérisé par une fonction endoglycosidase inconnue. / Pseudomonas aeruginosa (Pa) is a Multidrug-Resistant bacterium responsible for more than 10% of nosocomial infections in Europe. Interestingly, Pa can switch its lifestyle between planktonic (acute infection) and sessile lifestyle (biofilm-type chronic infection) through different regulatory pathways, in which GacS/GacA Two Component System (TCS) plays a central decisive role. An active homodimer form of GacS Histidine Kinase (HK) leads to biofilm formation, while the inhibition of GacS by the hybrid HK RetS via cytoplasmic hetero-dimerization promotes acute infection. During my thesis, we unveiled for the first time the sensing role of the periplasmic detection domain of GacS HK (GacSp). I further solved the 3D structure of GacSp using NMR spectroscopy revealing its PDC-like fold, which characterizes a large number of detection domains known to bind a wide range of ligands. The structural analyses of the new GacSp structure suggest a conserved ligand-binding pocket. All together, my results present structural and functional understanding of GacSp role, which form the basis to consider this domain as a new target for anti-biofilm therapy.In the second part of my thesis, I report a 2.5Å resolution crystal structure of a family 39 glycoside hydrolase member (GH39wh2) from the human gut bacteria B. cellulosilyticus WH2. GH39wh2 shares a similar architecture as found in other related GH39 members but unveils an atypical shallow solvent-exposed groove. Complementary biochemical and bioinformatics analyses assign GH39wh2 to a new GH39 subgroup harboring a yet unknown endoglycosidase activity.

One of the most crucial issues nowadays is the protection of the environment and the replacement of fossil fuels, which are abundantly used around the world, with more efficient and renewable sources. The highest portion of global energy demands today is used in heating and cooling purposes. One way of alleviating the fossil-based thermal energy uses is to harvest excess thermal energy using thermochemical storage materials (TCMs) for use at heating/cooling demands at different times and locations. Along this, in this master’s thesis, a bench-scale thermochemical heat storage (TCS) system is numerically designed, as a part of a collaborative project: Neutrons for Heat Storage (NHS), funded by Nordforsk. The TCS system that is designed herein employs the reversible chemical reaction of ammonia with a metal halide (MeX) for a heat storage capacity of 0.5 kWh, respectively releasing and storing heat during absorption and desorption of ammonia into and from the MeX. This system is designed for low temperature heat applications, around 40-80 °C. SrCl2 is chosen as the metal halide to be used, based on the research outcomes in determining the most suitable materials conducted by NHS project partners. In the ammonia-SrCl2 system, only the absorption and desorption between SrCl2∙NH3 and SrCl2∙8NH3 are considered. The main reason is because absorption/desorption between the last ammine and SrCl2 undergoes at a significantly higher/lower reaction pressure (for a given temperature), with a significant volume change compared to the rest of the ammines, and therefore is practically less cost effective. This thesis also includes a detailed discussion of four different thermochemical storage designs from literature, found as the most relevant to the present TCS system study, which use the reaction between ammonia and metal halides. The first system that was examined is a TCS system built by the NHS project partners at Technical University of Denmark (DTU), owing to its similarities with the desired project, regarding the design and parameters the system uses. This system works in batch mode, only allowing either absorption (i.e. heat release) or desorption (i.e. heat storage) at a given cycle. Thus, upgrading the design of this TCS system at DTU is considered as a most-likely solution to the research objectives of this current thesis project. Moreover, the TCS system at DTU uses storage conditions and desorption temperature similar to the current project’s desired low temperature range of 40-80 °C. The second system discussed herein from literature uses two reactors for cold and heat generation, which means that both charging and discharging processes occur simultaneously. This simultaneous operability is the main reason that this particular system was examined in this thesis. The next discussed system from literature also uses two reactors, for absorption and desorption processes, which work reversibly when each process is completed, like in the desired concept of this project. These two systems (i.e., the secondly and the thirdly discussed systems) use the reversible solid-gas reaction for absorption and desorption between SrCl2∙NH3 and SrCl2∙8NH3, however, the conditions of pressure and temperature between them differ. The second system from literature operates at desorption and absorption at respective conditions of 96 °C, 15 bar and 87 °C, 11 bar while the third system discussed operates at 103 °C, 16 bar and 59 °C, 3 bar during desorption and absorption respectively. The last system from literature that is discussed herein provides the same desorption temperature of 80 °C. Inaddition this particular study suggests that the reaction of solid with gaseous NH3 is better (than the solid with liquid NH3 reaction) based on results derived from several different low-pressure experiments of the reactions. The main differences between all these discussed systems from literature, as opposed to the desired TCS system design in this thesis project, concern the systems’ operating mode and the pressure and temperature-conditions. The first difference is that only one of the examined systems pumps the solid VIII powder salt around the system in contrast to the others that keep the salt static inside the reactors and pumped only the ammonia around the system, as chosen in the current system. The second difference concerns the operating conditions during absorption and desorption reactions, where these different systems operate at a widely different pressure and temperature conditions as compared to the current system expectations. Thus, there are four main lessons that were learnt via this literature analysis, to improve the TCS system at DTU to the desired new system in this work. The first lesson is related to the reactants’ transportation mechanism that should be used in this system. Regarding this, it was decided to maintain the solid salt (metal halide) stationary inside each reactor (but not pumping it instead of ammonia), similar to the majority of designs discussed from literature. According to the second and third lessons, the solid-gas reaction is the most suitable solution and only the reactions of absorption and desorption between SrCl2∙NH3 and SrCl2∙8NH3 are considered, following the experience from literature (for the reasons explained earlier). The last lesson regards the system’s suitable operating conditions and more specifically the TCS system’s temperatures that should match the district heating temperatures. Thus, the temperature point that was chosen as a priority was 80 °C, from the range 40- 80 °C set in the partner project NHS. To maintain this condition, therefore, the most suitable condition of pressure of both reactions (according to the equilibrium pressure vs temperature curve) was chosen to be at around 8 bar. This same pressure was chosen for both reactions, since the pressure difference between these reactors and the storage of ammonia (i.e. from 8 to 10 bar) should be as small as possible due to the high costs that can arise in the case of a higher pressure difference (i.e. requiring more compressors and heat exchangers). Inspired by these literature cases, firstly a conceptually suitable TCS system was proposed in this project and after that the final desired system was designed and was implemented and evaluated numerically. The numerical design and optimization of the chosen TCS system was performed herein by using the software Aspen Plus (version 9), which contains both fluids and solids in a simulation environment, using consistent physical properties. This TCS system is designed to store and release heat at around 80 °C and 8 bar through absorption and desorption by using two identical reactors respectively. Each reactor includes the amount of around 1 kg (more specifically 0.985 kg) strontium chloride salt reacting with 1.7 kg of ammonia. A verification system is also modelled in Aspen, using available experimental data from literature. Here, the modelled novel system design was adapted to this chosen other system layout from literature which uses the same reaction pair, yet at different operating conditions. This adapted system design in Aspen was then used to verify the chosen configuration and the reliability of the constructed system for the NHS project. Good agreements between the modelled results in Aspen against the available experimental data of this verification model are obtained. A sensitivity analysis is also conducted herein on the proposed novel TCS system to identify the optimum operating conditions and the behaviour of the chosen most important parameters of the system. The designed system provides an energy storage capacity of 0.5 kWh for the specific amounts (in volumetric flow rates) of ammonia and monoammine of strontium chloride, that comes from the analysis, of 1.08696 e-05 kmol/s and 1.5528 e-06 kmol/s respectively. For these specific values of the HTF, the analysis showed that the volumetric flow rates of the heat and cold external sources must be 1.56 l/min (which is decreasing with the increase of the inlet HTF temperature) and 0.42 l/min (which is increasing with the increase of the inlet HTF temperature) respectively. In conclusion, this study presents an ammonia-SrCl2 TCS benchscale system design that allows continuous heat storage and release, in an easy-to-scale up design, also suggesting optimum operating conditions. / En av de mest avgörande frågorna i dag är skyddet av miljön och utfasningen av fossila bränslen som används allmänt över hela världen för mer effektiva och förnybara resurser. Den största delen av den globala energibehovet idag avser uppvärmnings- och kylapplikationer. Ett sätt att minska fossilbaserad termiskenergianvändning är att lagra överskottsvärmeenergi genom termokemiska lagringsmaterial (TCM) och använda den för värme- och kylbehov vid olika tidpunkter och platser. I samband med detta är ett termokemiskt värmelagringssystem numeriskt utformat i detta mastersexamensprojekt, som en del av ett samarbetsprojekt Neutrons for Heat Storage (NHS) finansierat av Nordforsk. Det termokemiska lagringssystemet (TCS) som är konstruerat utnyttjar den reversibla kemiska reaktionen av ammoniak med en metallhalogenid (MeX) för en värmelagringskapacitet på 0.5 kWh, och frigör och lagrar värme respektive under absorption och desorption av ammoniak till och från MeX. Systemet är designat för lågtemperaturuppvärmningstillämpningar runt 40-80 °C. SrCl2 väljs som det mest lämpliga metallhalogeniden för systemet, baserat på studier som utförts av NHS-projektpartnerna. I ammoniak SrCl2-systemet beaktas endast absorption och desorption mellan SrCl2NH3 och SrCl28NH3. De huvudsakliga orsakerna till detta är att absorptionen/desorptionen mellan den sista aminen och SrCl2 kräver ett betydligt högre/lägre reaktionstryck (för en given temperatur), och resulterar i en betydande volymförändring jämfört med resten av aminerna, och är därför praktiskt taget mindre kostnadseffektivt. Detta mastersexamensprojekt inkluderar en detaljerad genomgång av fyra olika TCS-system från litteratur som använder reaktionen mellan ammoniak och metallhalogenider. Dessa väljs här eftersom dessa anses vara de mest relevanta (från litteratur) jämfört med det valda systemet i denna studie. Det första undersökta systemet är ett system byggt av NHS-projektpartnerna vid Danmarks Tekniska Universitet (DTU). Detta har valts på grund av likheterna med det önskade systemet i det aktuella mastersexamensprojektet, vad gäller systemdesign och parametrar. Detta system fungerar i batch-läge, vilket endast tillåter antingen absorption (dvs värmeavgivning) eller desorption (dvs värmelagring) under en specifik cykel. Således kan en uppgraderad design av detta TCS-system vid DTU möjligen vara en lämplig lösning på forskningsmålen för detta mastersexamensprojekt. Dessutom använder detta TCS-system från DTU ganska liknande driftsförhållanden (temperaturer och tryck) i nivå med det aktuella projektets önskade lågtemperaturintervall på 40-80 °C. Det andra systemet från den litteratur som diskuterats använder två reaktorer för kyla och värmeproduktion, vilket innebär att både laddningsoch urladdningsprocesser sker samtidigt. Denna samtidiga operation är främst anledningen till att systemet undersöktes, eftersom detta är en önskad funktion att uppnå i det aktuella projektet. Nästa system från den litteratur som diskuteras häri använder också två reaktorer för absorptions- och desorptionsprocesser, som fungerar reversibelt när varje process är klar, precis som önskat i detta projekt. Dessa två system (dvs det andra och det tredje diskuterade systemen) använder den reversibla fastgasreaktionen för absorption och desorption mellan SrCl2NH3 och SrCl28NH3, dock vid olika tryck- och temperaturförhållanden. Det andra systemet arbetar nämligen under kombinationer av absorption och desorption av 96 °C, 15 bar och 87 °C, 11 bar, medan det tredje systemet arbetar vid 103 °C, 16 bar respektive 59 °C, 3 bar. Det sista systemet som diskuterats från litteraturen arbetar vid samma temperatur som det önskade systemet gör (dvs. 80 ° C) och genom olika lågtrycksexperiment visar att den fasta salt-gasreaktionen är ett bättre val än reaktionen av det fasta saltet med flytande gasreaktion. De viktigaste skillnaderna mellan alla dessa diskuterade system från litteratur i motsats till det önskade TCS-system i detta mastersexamensprojekt, avser systemdriftläge samt deras tryck och X temperaturförhållanden. Den första skillnaden är att endast ett av alla undersökta system pumpar saltet i fast pulverform, till skillnad från de andra som håller saltet stillastående i reaktorerna och endast pumpar ammoniak. Den andra skillnaden gäller driftsförhållandena under absorptions- och desorptionsreaktioner där dessa system arbetar vid mycket olika tryck- och temperaturförhållanden jämfört med det nuvarande systemet. Således, från översynen av alla system, finns det fyra huvudsakliga lärdomar för att förbättra TCS-systemet vid DTU till det önskade nya systemet. Den första är relaterad till reaktanttransportmekanismen som bör användas i detta system. I detta avseende har det beslutats att hålla det fasta saltet (metallhalogenid) stillastående i varje reaktor (men inte pumpa det istället för ammoniak), till skillnad från de flesta system i litteraturen. Enligt dem andra och tredje lektionerna är den fasta gasreaktionen den mest lämpliga lösningen och endast reaktionerna på absorption och desorption mellan SrCl2∙NH3 och SrCl2∙8NH3 bör övervägas enligt erfarenheten från litteraturen (av de skäl som förklarats tidigare). Den sista lärdomen avser systemets lämpliga driftsförhållanden och mer specifikt TCS-systemets temperaturer för att matcha fjärrvärmetemperaturerna. Den temperaturpunkten valts som prioritet, från området 40-80 °C inställt av moderprojektet NHS, sattes till 80 °C. För att bibehålla detta tillstånd var det lämpligaste tryckvillkoret för båda reaktionerna (enligt jämviktstrycket kontra temperaturkurva) valdes att ligga på cirka 8 bar. Samma tryck valdes för båda reaktionerna, eftersom tryckskillnaden mellan dessa reaktorer och lagring av ammoniak (dvs. från 8 till 10 bar) borde vara så liten som möjligt på grund av de höga kostnaderna som kan uppstå vid högre tryckskillnad (dvs. fler kompressorer krävs och värmeväxlare). Inspirerad av denna litteratur föreslogs för det första ett konceptuellt lämpligt TCS-system i detta mastersexamensprojekt, varefter det slutliga systemet implementerades och utvärderades numeriskt för de önskade förhållandena. Den numeriska utformningen och optimeringen av det valda TCS-systemet utfördes här med hjälp av programvaran Aspen Plus (version 9), som innehåller både vätskor och fasta ämnen i en simuleringsmiljö, med konstant fysiska egenskaper. Detta TCS-system är utformat för att lagra och släppa värme vid cirka 80 °C och 8 bar genom absorption och desorption med användning av två identiska reaktorer respektive. Varje reaktor innefattar cirka 1 kg (närmare bestämt 0.985 kg) strontiumkloridsalt reagerande med 1.7 kg ammoniak. Ett verifieringssystem modelleras också i Aspen med hjälp av tillgängliga experimentella data från litteraturen. I detta anpassades den modellerade nya systemdesignen till denna valda andra verifieringssystemlayout från litteratur, som använder samma reaktionspar, men under olika driftsförhållanden. Denna anpassade systemdesign i Aspen användes sedan för att verifiera den valda konfigurationen och tillförlitligheten för det designade systemet för NHS-projektet. Här erhålls ett bra avtal för denna verifieringssystemdesign mellan Aspenmodellresultaten och experimentdata. Här utförs också en känslighetsanalys för det utformade TCSsystemet i det aktuella projektet för att identifiera de optimala driftsförhållandena och beteendet för de valda viktigaste parametrarna i systemet. Det konstruerade systemet ger en energilagringskapacitet på 0.5 kWh för de specifika mängderna (i volymflöde) av ammoniak och monoamin av strontiumklorid, som kommer från analysen, av 1.08696 e-05 kmol/s och 1.5528 e-06 kmol/s respektive. För dessa specifika värden på värmeöverföringsvätskan visade analysen att de volymetriska flödeshastigheterna för värme och kalla yttre källor måste vara 1.56 l/min (vilket minskar när temperaturen på värmeöverföringsvätskan ökar) och 0.42 l/min (som ökar när temperaturen på värmeöverföringsvätskan ökar). Sammanfattningsvis presenterar denna studie ett ammoniak-SrCl2 TCS-bänkskålsystem som möjliggör kontinuerlig värmelagring och frigöring, har en design som är lätt att anpassa och föreslår också optimala driftsförhållanden.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Orientador: Prof. Dr. Carlos Bruno Reissmann / Co-orientadores: Profª Drª Celina Wisniewski e Dr. Sergio Gaiad / Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Ciências do Solo. Defesa: Curitiba, 2007 / Inclui bibliografia

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Submitted by JULIE ANNE ESPÍNDOLA AMORIM (julie__anne@hotmail.com) on 2018-06-05T18:33:56Z No. of bitstreams: 1 Tese_23-03-18-final_corrigida_05-06-2018_Juliecorrigidapdf.pdf: 3073465 bytes, checksum: 1673cd431dca7fe8472ab9ce8185182f (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-06-05T18:59:54Z (GMT) No. of bitstreams: 1 amorim_jae_dr_jabo.pdf: 3073465 bytes, checksum: 1673cd431dca7fe8472ab9ce8185182f (MD5) / Made available in DSpace on 2018-06-05T18:59:54Z (GMT). No. of bitstreams: 1 amorim_jae_dr_jabo.pdf: 3073465 bytes, checksum: 1673cd431dca7fe8472ab9ce8185182f (MD5) Previous issue date: 2018-04-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O cancro cítrico tipo A, causado pela bactéria Xanthomonas citri subsp. citri (XccA), é uma das doenças de citros mais importantes, afetando todas as cultivares comerciais, para a qual não existem ainda estratégias de controle eficientes. Os genes ntrB e ntrC codificam, respectivamente, a histidina quinase (HK) e o regulador de respostas (RR), pertencentes a um sistema de dois componentes (TCSs), que atuam no sistema regulador de nitrogênio (NTR). Porém, o possível papel desses genes na virulência da XccA e de outros fitopatógenos ainda não foi elucidado. Este estudo teve como objetivo investigar os efeitos dos genes ntrB e ntrC no desenvolvimento do cancro cítrico em limão-cravo (Citrus limonia Osbeck), bem como a possível relação desses genes com a regulação da expressão de genes do sistema de secreção tipo 3 (SST3), considerado um dos principais fatores de virulência da XccA. Os mutantes ΔntrB e ΔntrC foram obtidos pela técnica de mutagênese sítio-dirigida por reação em cadeia da polimerase de extensão por sobreposição. A mutação dos genes causou redução na sintomatologia do cancro cítrico e diminuição da população bacteriana no espaço intercelular do tecido foliar da planta. A análise das curvas de crescimento in vitro revelou que a ausência do gene ntrB não alterou a viabilidade da bactéria, enquanto a mutação do gene ntrC afetou o “fitness” bacteriano em meio de cultura NB. Análises in vitro indicaram que o mutante ΔntrC formou duas vezes mais biofilme e produziu cinco vezes mais goma xantana do que a XccA 306 in vitro. A expressão dos genes (hpa1, hrpG, hrpX, hrpE, hrpW e hrpD6) do SST3 avaliados foi significativamente maior (p < 0,05) no mutante ΔntrC do que na XccA 306 e no ΔntrB, indicando que ntrC possa atuar na regulação do SST3. Porém, o nível de expressão desses genes no mutante ΔntrB não apresentou diferença significativa (p > 0,05) em relação à XccA 306. A modelagem molecular revelou semelhança estrutural entre as regiões receptoras de NtrC e HrpG, sugerindo que a fosforilação de HrpG por NtrB possa ocorrer in vivo. Em síntese, os resultados obtidos neste estudo indicam que a mutação dos genes ntrB e ntrC afeta o desenvolvimento do cancro cítrico em limão-cravo e que o gene ntrC pode atuar na regulação dos mecanismos de formação de biofilme, produção de goma xantana e expressão de genes do SST3 e/ou que a ausência desse gene ocasione um desequilíbrio celular na XccA 306, resultando na alteração desses mecanismos, enquanto NtrB pode apresentar papel na regulação de genes do SST3 por meio da fosforilação de HrpG. / The citrus canker type A, provoked by the bacterium Xanthomonas citri subsp. citri (XccA), is one of themost important citrus diseases, affecting all the commercial cultivars, for which there are no effective control strategies. The ntrB and ntrC genes encode a histidine kinase (HK) and the response regulator (RR), respectively, belong to a two-component system (TCSs), related to the nitrogen regulatory system (NTR). However, the possible role of ntrB and ntrC genes in the virulence of XccA and other phytopathogens has not yet been elucidated. Therefore, the aim of this study was to investigate the impact of the ntrB and ntrC genes on the development of citrus canker in rangpur lime (Citrus limonia Osbeck), as well as the possible relation of ntrB and ntrC genes with the regulation of the type 3 secretion system (T3SS) gene expression, which is considered one of the main virulence factors of XccA. The ΔntrB and ΔntrC were obtained by site-directed mutagenesis through overlap extension polymerase chain reaction. The mutation of the ntrB and ntrC genes caused a reduction of the citrus canker symptoms, and decrease of the bacterial population in the intracellular space of the foliar tissue of the plant. In vitro growth curves analysis revealed that the ΔntrB did not affect the viability of the bacterium, whereas the ΔntrC affected the bacterial fitness in NB culture medium. In vitro analysis indicated that the ΔntrC formed 2x more biofilm, and produced 5x xanthan gum compared to the XccA 306. The T3SS related genes (hpa1, hrpG, hrpX, hrpE, hrpW and hrpD6) expression was significantly higher (p <0.05) in the ΔntrC than in the XccA 306 and the ΔntrB, indicating that ntrC can modulate the regulation of T3SS. However, the level of expression of these genes in the ΔntrB did not differ (p> 0.05) in relation to the XccA 306. Molecular modeling revealed structural similarity between NtrC and HrpG receptors motifs, suggesting that phosphorylation of HrpG by NtrB may occur in vivo. Overall, the results obtained in this study strongly suggest that the mutation of the ntrB and ntrC genes affect the development of rangpur lime citrus canker and that ntrC gene may play an important role in the regulation of the mechanisms of biofilm formation, xanthan gum production and T3SS gene expression and/or that the absence of this gene causes a cellular imbalance in XccA 306 resulting in the alteration of these mechanism, whereas the NtrB may have a role with the regulation of T3SS genes by phosphorylation of HrpG. / 3385/2013