Wheat is the most economically important crop forming one quarter of Australian farm production. The wheat industry is severely affected by diseases, with fungal pathogens causing the most important economic losses in Australia. The application of fungicides and chemicals can control crop diseases to a certain extent, however, it is expensive and public concern for the environment has led to alternative methods of disease control to be sought, including the use of microorganisms as biological control agents. Microorganisms are abundant in the soil adjacent to plant roots (rhizosphere) and within healthy plant tissue (endophytic) and a proportion possess plant growth promotion and disease resistance properties. Actinobacteria are gram-positive, filamentous bacteria capable of secondary metabolite production such as antibiotics and antifungal compounds. A number of the biologically active endophytes belonging to the Actinobacteria phylum were isolated in our laboratory. A number of these isolates were capable of suppressing the wheat fungal pathogens Rhizoctonia solani, Pythium sp. and Gaeumannomyces graminis var. tritici, both in vitro and in planta indicating the potential for the actinobacteria to be used as biocontrol agents. The aim of this research was to investigate the molecular mechanisms underlying this plant-microbe interaction. The indigenous microbial populations present in the rhizosphere and endophytic environment are critical to plant health and disruptions of these populations are detrimental. The culture-independent technique Terminal Restriction Fragment Length Polymorphism (T-RFLP) was used to characterise the endophytic actinobacteria population of wheat roots under different conditions. Soils which support a higher number of indigenous microorganisms result in wheat roots with higher endophytic actinobacterial diversity and level of colonisation. Sequencing of 16S rRNA gene clones, obtained using the same actinobacteria-biased PCR primers that were used in the T-RFLP analysis, confirmed the presence of the actinobacterial diversity, and identified a number of Mycobacterium and Streptomyces species. It was found that the endophytic actinobacterial population of the wheat plants contained a higher diversity of endophytic actinobacteria than reported previously, and that this diversity varied significantly among different field soils. The endophytic actinobacteria have previously been shown to protect wheat from disease and enhance growth when coated onto the seed before sowing. As the endophytes isolated were recognised as potential biocontrol agents, the impact on the indigenous endophytic microbial population was investigated. Utilising the T-RFLP technique it was established that the use of a commercial microbial inoculant, containing a large number of soil bacterial and fungal strains applied to the soil, disrupts the indigenous endophyte population present in the wheat roots. The hypothesis is that non-indigenous microbes proliferate and dominate in the soil preventing a number of endophytic-competent actinobacterial genera from access to the seed and ultimately endophytic colonisation of the wheat roots. This dramatically reduces diversity of endophytes and level of colonisation. In contrast the use of a single endophytic actinobacteria endophyte inoculant results in a 3-fold increase in colonisation by the added inoculant, but does not significantly affect this indigenous population. Colonisation of healthy plant tissues with fungal endophytes has been shown to improve the competitive fitness with enhanced tolerance to abiotic and biotic stress and improved resistance to pathogens and herbivores. In this study the fungal endophyte population of wheat plants grown in four different soils was analysed using partial sequencing of 18S rRNA gene sequences. Sequence anlaysis of clones revealed a diverse range of fungal endophytes. In this diverse range of fungal endophytes a number sequences were highly similar to those of previously known fungal phytopathogens. A number of sequences detected were similar to fungal species previously identified in soil or plant material but not as endophytes. The remaining sequences were similar to fungal species without a known relationship with plants. Plants have developed an inducible mechanism of defence against pathogens. In addition to local responses plants have developed a mechanism to protect uninfected tissue through a signal that spreads systemically inducing changes in gene expression. In the model plant Arabidopsis thaliana activation of the Systemic Acquired Resistance (SAR) pathway and the Jasmonate (JA)/Ethylene (ET) pathway is characterised by the production of pathogenesis-related (PR) and antimicrobial proteins resulting in systemic pathogen resistance. Endophytic actinobacteria, isolated from healthy wheat roots in our laboratory, have been shown to enhance disease resistance to multiple pathogens in wheat when coated onto the seed before sowing. Real Time RT-PCR was used to determine if key genes in the SAR and JA/ET pathways were induced in response to inoculation with endophytic actinobacteria. Inoculation of wild-type Arabidopsis thaliana with selected strains of endophytic actinobacteria was able to �prime� the defence pathways by inducing low level expression of SAR and JA/ET genes. Upon pathogen infection the defence-genes are strongly up-regulated and the endophyte coated plants had significantly higher expression of these genes compared to un-inoculated plants. Resistance to the bacterial pathogen Erwinia carotovora subsp. carotovora was mediated by the JA/ET pathway whereas the fungal pathogen Fusarium oxysporum triggered primarily the SAR pathway. Further analysis of the endophytic actinobacteria-mediated resistance was performed using the Streptomyces sp. EN27 and Arabidopsis defence-compromised mutants. It was found that resistance to E. carotovora subsp. carotovora mediated by Streptomyces sp. EN27 occurred via a NPR1-independent pathway and required salicylic acid whereas the jasmonic acid and ethylene signalling molecules were not essential. In contrast resistance to F. oxysporum mediated by Streptomyces sp. EN27 occurred via a NPR1-dependent pathway but also required salicylic acid and was JA- and ET-independent. This research demonstrated that inoculating wheat with endophytic actinobacteria does not disrupt the indigenous endophytic population and may be inducing systemic resistance by activating defence pathways which lead to the expression of antimicrobial genes and resistance to a broad range of pathogens.

Most rice protection methods have currently used toxic chemicals to control pathogens and pests, which leads to environmental pollution. Systemic acquired resistance (SAR) taking advantage of natural defence reaction of plants could be proposed as an alternative, ecologically friendly approach for plant protection. Its application into rice production could minimize the chemicals quantity used and could contribute to the decrease of environmental pollution and the development of sustainable agriculture. The research was conducted to select the most effective chemical and suitable method to improve the health of rice plants infected by grassy stunt disease in net-house of Can Tho University. SAR chemicals were used at very low concentrations (in mM). Results showed that the height of rice plants treated with SAR chemicals was higher than that of plants untreated. Besides, the number of diseased plants was reduced and the ratio of firm grain and yield increased when plants were applied by SAR. Among the used substances, oxalic acid provided the best systemic acquired resistance. With oxalic acid, seed soaking was better than seed coating in systemic acquired resistance against rice grassy stunt disease. / Hầu hết các phương pháp sản xuất lúa hiện nay đều sử dụng các hóa chất độc hại trong việc phòng trừ bệnh và côn trùng gây hại, nên dẫn đến ô nhiễm môi trường. Kích thích tính kháng lưu dẫn giúp kích hoạt cơ chế tự nhiên kháng bệnh của cây có thể là giải pháp bảo vệ thực vật thay thế an toàn với môi trường. Việc ứng dụng tiến bộ này vào trong sản xuất lúa có thể làm giảm lượng hóa chất sử dụng, đóng góp vào việc giảm thiểu ô nhiễm môi trường và sự phát triển của một nền nông nghiệp bền vững. Nghiên cứu đã được thực hiện tại nhà lưới trường Đại học Cần Thơ để tuyển chọn hóa chất và phương pháp sử dụng hóa chất để tăng cường sức khỏe giúp cây lúa vượt qua bệnh vàng lùn. Hóa chất kích kháng được sử dụng ở một nồng độ rất thấp (đơn vị là mM). Kết quả cho thấy chiều cao cây lúa khi xử lý chất kích kháng tốt hơn so đối chứng không xử lý. Bên cạnh đó, số cây lúa nhiễm bệnh giảm, tỉ lệ hạt chắc và năng suất tăng khi cây lúa được xử lý với chất kích kháng. Trong số các chất kích kháng đã sử dụng, acid oxalic cho hiệu quả vượt trội. Với chất acid oxalic, phương pháp ngâm hạt cho hiệu quả kích kháng tốt hơn phương pháp áo hạt.

Cancer is a set of complex genetic diseases driven by diverse genomic alterations. The genomic study of cancer has enabled the discovery of novel, targetable events in almost all cancer types and in turn, has led to the development of new, targeted cancer therapies benefiting patients; however, the recent explosion of genomic datasets has also resulted in huge lists of new oncogenic factors of unknown biological relevance, and uncertainty over how best to use the data appropriately to influence patient care. Some of the most pressing questions surround the use of statistical methods to identify actionable genomic alterations in cancer and the identification of driving oncogenes in the context of the genomic evolution of cancer cells, undergone before, during, and after prolonged treatment regimens.

Systemic acquired resistance (SAR) is initiated upon recognition of specific microbial effectors by cognate plant resistance proteins and immunizes distal tissues of plants against secondary infections. SAR involves the generation of a mobile signal at the site of primary infection, which then translocates to and activates defense responses in the distal tissues via some unknown mechanism(s). This study shows that an ACYL CARRIER PROTEIN 4 (ACP4), GLABRA1 (GL1) and ACYL CARRIER BINDING PROTEINS (ACBP) are required for the processing of the mobile SAR signal in distal tissues of Arabidopsis. Although acp4, gl1 and acbp plants generate the mobile signal, they are unable to respond to this signal to induce systemic immunity. A defective SAR in acp4, gl1 and acbp plants is not associated with salicylic acid (SA)-, methyl SA-, or jasmonic acid-mediated pathways but is related to the presence of an abnormal cuticle on acp4, gl1 and acbp plants. Other genetic mutations impairing the cuticle also compromised SAR. An intact cuticle was only necessary during the time when the mobile signal is generated and translocated to the distal tissues. A novel role for the plant cuticle as the site for SAR-related molecular signaling is demonstrated.

Plants use several strategies to defend themselves against microbial pathogens. These include basal resistance, which is induced in response to pathogen encoded effector proteins, and resistance (R) protein-mediated resistance that is activated upon direct or indirect recognition of pathogen encoded avirulence protein(s). The activation of Rmediated signaling is often associated with generation of a signal, which, upon its translocation to the distal uninfected parts, confers broad-spectrum immunity against related or unrelated pathogens. This phenomenon known as systemic acquired resistance (SAR) is one of the well-established forms of induced defense response. However, the molecular mechanism underlying SAR remains largely unknown. Induction of plant defense is often associated with a fitness cost, likely because it involves reprogramming of the energy-providing metabolic pathways. Glycerol metabolism is one such pathway that feeds into primary metabolism, including lipid biosynthesis. In this study, I evaluated the role of glycerol-3-phosphate (G3P) in host-pathogen interaction. Inoculation with the hemibiotrophic fungal pathogen Colletotrichum higginsianum led to increased accumulation of G3P in wild-type plants. Mutants impaired in biosynthesis of G3P showed enhanced susceptibility, suggesting a correlation between G3P levels and basal defense. Conversely, increased biosynthesis of G3P correlated with enhanced resistance. The Arabidopsis genome encodes one copy of glycerol kinase (GK), which catalyzes phosphorylation of glycerol to G3P, and five copies of G3P dehydrogenase (G3Pdh), which catalyze reduction of dihydroxyacetone phosphate to G3P. Analysis of plants mutated in various G3Pdh's showed that plastidal lipid biosynthesis was only dependent on the GLY1 isoform but the pathogen induced G3P pool required the function of GLY1 and two other G3Pdh isoforms. Interestingly, compromised G3P biosynthesis in GK and G3Pdh mutants also compromised SAR, which was restored when G3P was provided exogenously. Detailed biochemical analysis showed that G3P was transported to distal tissues and that this process was dependent on a lipid transfer protein, DIR1. Together, these results show that G3P plays an important role in both basal- and induced-defense responses.

Claritromicina era considerada um antibiótico de escolha para infecções causadas pelo complexo Mycobacterium abscessus, entretando, recentemente falhas no tratamento com este antibiótico têm sido reportadas. A resistência adquirida a claritromicina está relacionada à mutações pontuais que acarretam substituição da adenina na posição 2058 ou na posição 2059 na região do gene rrl que codifica o domínio peptidil transferase do rRNA 23S. Um mecanismo secundário de resistência à claritromicina tem sido descrito como resistência induzida, que é conferida pelo polimorfismo T/C no nucleotídeo 28 do gene erm(41). A resistência adquirida pode ser detectada em até 3 dias de incubação do M. abscessus com a claritromicina enquanto que a resistência induzida requer mais do que 5 dias de incubação. Por outro lado, o uso de marcadores moleculares para detecção de resistência adquirida e induzida no complexo M. abscessus têm sido propostos. O objetivo desse estudo foi avaliar o perfil de suscetibilidade e os marcadores moleculares de resistência à claritromicina no complexo M. abscessus. Um total de 42 isolados de um estudo prévio de vigilância, entre os anos 2007 e 2013 foram utilizados. O perfil de suscetibilidade para a claritromicina foi determinado por microdiluição em caldo com leituras em 3, 5, 7 e 14 dias. Mutações nos genes rrl e erm(41) foram avaliados por PCR com primers específicos e posterior sequenciamento. Resistência à claritromicina, em até 3 dias de incubação, foi observada em 31 dos 42 (73,8%) isolados. Resistência induzida à claritromicina foi observada em 6 de 11 (54,5%) isolados que apresentaram resistência após 5 ou 7 dias de incubação. Todos os isolados com resistência induzida foram M. abscessus subsp. massiliense. Além disso, todos os 28 isolados de M. abscessus subsp. massiliense apresentaram deleção em erm(41). Apenas cinco isolados foram sensíveis à claritromicina após 14 dias de incubação. Nenhum dos 42 isolados apresentaram mutação pontual na região de peptidil transferase do rRNA 23S e todos os isolados apresentaram o polimorfismo T/C no nucleotídeo 28 do gene erm(41). Os dados deste estudo indicam a falta de correlação dos marcadores moleculares com a expressão de resistência à claritromicina. / Infections due to Mycobacterium abscessus complex used to respond to clarithromycin treatment but more recently treatment failure with this antibiotic has been reported. Acquired resistance to clarithromycin is related to substitutions at the adenine either at position 2058 or at position 2059 in a region of the rrl gene encoding to the peptidyltransferase domain of the 23S rRNA. A secondary mechanism related to clarithromycin resistance has been described as an inducible resistance, conferred by T/C polymorphism at the 28th nucleotide in erm(41) gene. Acquired resistance can be detected up to 3 days of incubation of the M. abscessus with the clarithromycin while inducible resistance requires more than 5 days of incubation. Molecular markers to detect acquired and inducible resistance in M. abscessus complex isolates were proposed. This study evaluated the profile of susceptibility and the molecular markers of clarithromycin resistance in M. abscessus complex. A total of 42 isolates from a previous surveillance study (2007 to 2013) were used in this study. The susceptibility profile for clarithromycin was determined by broth microdilution with reads at 3, 5, 7 and 14 days. Mutations in rrl and erm(41) genes were evaluated by PCR with specific primers followed by sequencing. Clarithromycin resistance, up to 3 days of incubation, was observed in 31 of 42 (73.8%) isolates. Inducible clarithromycin resistance was observed in 6 of 11 (54.5%) isolates which presented resistance only after 5 or 7 days of incubation. All isolates with inducible resistance were identified as M. abscessus subsp. massiliense. Moreover, all 28 M. abscessus subsp. massiliense had a deletion in erm(41). Only five isolates proved to be susceptible to clarithromycin after 14 days of incubation. None of the 42 isolates presented a point mutation in the peptidyltransferase region of the 23S rRNA (rrl) and all isolates presented the T/C polymorphism at the 28th nucleotide of the erm(41) gene. The data of this study indicates a lack of correlation of molecular markers of clarithromycin resistance for both acquired and inducible resistance to clarithromycin.

Claritromicina era considerada um antibiótico de escolha para infecções causadas pelo complexo Mycobacterium abscessus, entretando, recentemente falhas no tratamento com este antibiótico têm sido reportadas. A resistência adquirida a claritromicina está relacionada à mutações pontuais que acarretam substituição da adenina na posição 2058 ou na posição 2059 na região do gene rrl que codifica o domínio peptidil transferase do rRNA 23S. Um mecanismo secundário de resistência à claritromicina tem sido descrito como resistência induzida, que é conferida pelo polimorfismo T/C no nucleotídeo 28 do gene erm(41). A resistência adquirida pode ser detectada em até 3 dias de incubação do M. abscessus com a claritromicina enquanto que a resistência induzida requer mais do que 5 dias de incubação. Por outro lado, o uso de marcadores moleculares para detecção de resistência adquirida e induzida no complexo M. abscessus têm sido propostos. O objetivo desse estudo foi avaliar o perfil de suscetibilidade e os marcadores moleculares de resistência à claritromicina no complexo M. abscessus. Um total de 42 isolados de um estudo prévio de vigilância, entre os anos 2007 e 2013 foram utilizados. O perfil de suscetibilidade para a claritromicina foi determinado por microdiluição em caldo com leituras em 3, 5, 7 e 14 dias. Mutações nos genes rrl e erm(41) foram avaliados por PCR com primers específicos e posterior sequenciamento. Resistência à claritromicina, em até 3 dias de incubação, foi observada em 31 dos 42 (73,8%) isolados. Resistência induzida à claritromicina foi observada em 6 de 11 (54,5%) isolados que apresentaram resistência após 5 ou 7 dias de incubação. Todos os isolados com resistência induzida foram M. abscessus subsp. massiliense. Além disso, todos os 28 isolados de M. abscessus subsp. massiliense apresentaram deleção em erm(41). Apenas cinco isolados foram sensíveis à claritromicina após 14 dias de incubação. Nenhum dos 42 isolados apresentaram mutação pontual na região de peptidil transferase do rRNA 23S e todos os isolados apresentaram o polimorfismo T/C no nucleotídeo 28 do gene erm(41). Os dados deste estudo indicam a falta de correlação dos marcadores moleculares com a expressão de resistência à claritromicina. / Infections due to Mycobacterium abscessus complex used to respond to clarithromycin treatment but more recently treatment failure with this antibiotic has been reported. Acquired resistance to clarithromycin is related to substitutions at the adenine either at position 2058 or at position 2059 in a region of the rrl gene encoding to the peptidyltransferase domain of the 23S rRNA. A secondary mechanism related to clarithromycin resistance has been described as an inducible resistance, conferred by T/C polymorphism at the 28th nucleotide in erm(41) gene. Acquired resistance can be detected up to 3 days of incubation of the M. abscessus with the clarithromycin while inducible resistance requires more than 5 days of incubation. Molecular markers to detect acquired and inducible resistance in M. abscessus complex isolates were proposed. This study evaluated the profile of susceptibility and the molecular markers of clarithromycin resistance in M. abscessus complex. A total of 42 isolates from a previous surveillance study (2007 to 2013) were used in this study. The susceptibility profile for clarithromycin was determined by broth microdilution with reads at 3, 5, 7 and 14 days. Mutations in rrl and erm(41) genes were evaluated by PCR with specific primers followed by sequencing. Clarithromycin resistance, up to 3 days of incubation, was observed in 31 of 42 (73.8%) isolates. Inducible clarithromycin resistance was observed in 6 of 11 (54.5%) isolates which presented resistance only after 5 or 7 days of incubation. All isolates with inducible resistance were identified as M. abscessus subsp. massiliense. Moreover, all 28 M. abscessus subsp. massiliense had a deletion in erm(41). Only five isolates proved to be susceptible to clarithromycin after 14 days of incubation. None of the 42 isolates presented a point mutation in the peptidyltransferase region of the 23S rRNA (rrl) and all isolates presented the T/C polymorphism at the 28th nucleotide of the erm(41) gene. The data of this study indicates a lack of correlation of molecular markers of clarithromycin resistance for both acquired and inducible resistance to clarithromycin.

Nos anos recentes, a atividade agrícola da citricultura vem enfrentando grandes problemas fitossanitários, principalmente, com relação à viabilidade econômica decorrente do controle das doenças. A bactéria Candidatus Liberibacter spp. está associada ao HLB, a principal doença que limita a produção das plantas cítricas. Assim, muitos pesquisadores têm voltado suas atenções para estudarem e encontrarem genes-alvo na resposta do hospedeiro a este patógeno para utilização no melhoramento genético. Nesse sentido, métodos de transformação genética das plantas cítricas são essenciais, porém características inerentes à espécie limitam seu cultivo in vitro e requerem um maior tempo para crescimento e propagação. Com isso, torna-se importante o estudo em plantas modelo, principalmente, para seguir protocolos de validação de genes. De acordo com o exposto, o gene EDS5 isolado de Citrus sinensis, associado ao mecanismo de Resistência Sistêmica Adquirida (SAR) foi superexpresso por meio da transformação genética em tomateiro (Solanum lycopersicum L. Micro-Tom). Após o crescimento dos brotos regenerados, foram identificadas as plantas positivas por meio de análise de GUS e PCR. Linhagens transgênicas homozigotas foram obtidas com avaliação da resistência ao antibiótico canamicina. / In the recent years, the agricultural activity of the citrus industry has been facing big phytosanitary problems, mainly with regard to economic viability arising from disease control. The bacterium Candidatus Liberibacter spp. is associated with HLB, the main disease that limits the production of citrus trees. Thus, many researchers have been returning their attentions to study and find target genes in the host response to this pathogen for use in the genetic improvement. In this way, methods of genetic transformation of citrus plants are essential, but the inherent characteristics of the species border your in vitro cultivation and require a longer time for growth and propagation. Therefore, it is important to study of model plants, mainly for genetic validation protocols. Thus, the EDS5 gene isolated from Citrus sinensis, associated with Systemic Acquired Resistance mechanism (SAR) was overexpressed by genetic transformation in tomato (Solanum lycopersicum L. Micro-Tom). After the growth of regenerated shoots, positive plants were identified by PCR and GUS analysis. Homozygous transgenic lines were obtained with evaluation of resistance to kanamycin.

A cultura da laranja doce é muito importante ao redor do mundo, em especial no Brasil, maior produtor mundial dessas frutas. A produção citrícola sempre esteve ameaçada por muitas doenças de grande importância, tais como, o cancro cítrico, a clorose variegada dos citros (CVC) e pinta preta. Entretanto, em 2004, surgiu o huanglongbing (HLB) ou greening, que tem devastado pomares, e para a qual ainda não foi encontrada uma solução definitiva. A transgenia pode ser uma técnica auxiliar no manejo desta doença com a busca de cultivares mais tolerantes, em especial ao HLB. Neste trabalho, as pesquisas de transgenia não envolveram genes exógenos à planta como, por exemplo, genes de outros organismos ou genes sintéticos, ou seja, foi baseado em tecnologias mais recentes já aplicadas em outras espécies vegetais, nas quais a transgenia é utilizada para super-expressar genes dos sistemas de defesa da própria planta. Estudos indicam que a super-expressão de genes do sistema de Resistência Sistêmica Adquirida (SAR - do inglês, \"Systemic Acquired Resistance\") promove a resistência de plantas a doenças. Um gene importante para esse sistema é o gene npr1 que controla a expressão das proteínas relacionadas à patogênese (PR), em especial a PR1. Junto do gene npr1, os genes npr3 e npr4 também são reguladores desse sistema, atuando sobre o gene npr1 de acordo com os níveis de ácido salicílico presentes na célula, nível este que varia de acordo com o nível de infecção de cada célula. Porém, a avaliação de um evento transgênico de citros pode levar muitos anos. Desta forma, para diminuir esse tempo de avaliação, pensou-se em usar plantas modelos. O sistema escolhido foi o tomateiro Micro-Tom (Solanun lycopersicum L. cv. Micro-Tom). Para a obtenção das construções gênicas, foram identificados os genes Csnpr1, Csnpr3 e Csnpr4 de Citrus sinensis L. Osbeck a partir dos genes Atnpr1, Atnpr3 e Atnpr4 de Arabidopsis thaliana L.. Os genes de citros foram obtidos a partir de uma planta de laranja doce por RT-PCR e clonados no vetor pCambia 2201, que foi então inserido em Agrobacterium tumefaciens para a transformação genética. Foi feita a transformação genética de plantas de laranja doce (Citrus sinensis L. Osbeck) e do tomateiro Micro-Tom. Após o crescimento dos brotos regenerados, foi feita a avaliação das plantas obtidas por meio de PCR. As plantas geneticamente modificadas foram aclimatizadas. As plantas de citros foram enxertadas e mantidas em casa de vegetação. As plantas de tomateiro Micro-Tom foram propagadas por sementes. A progênie foi avaliada aplicando o antibiótico de seleção canamicina, obtendo-se assim uma linhagem transgênica homozigota. / The sweet orange industry is very important worldwide, specially in Brazil, considered the world´s largest producer. The citrus production has always been threatened by several diseases of great importance, such as canker, CVC, and black spot. However, in 2004, the huanglongbing (HLB) or greening has been detected and devastated many citrus groves, and no definitive solution has been found yet. Transgenes may be a helpful tool for the management of this diseases, leading to the production of tolerant cultivars, especially to HLB. In this work, research on transgenic did not include the use of exogenous genes to the plant, such as genes from other organism or synthetic genes, i.e, it was based on new emerging technologies, already used on other crops, in which transgeny is used to super express genes from the plants own defense system. Studies indicate that a super expression of genes from the system called Systemic Acquired Resistance (SAR) promotes disease resistance. One important gene to this system is the npr1 gene, which controls the expression of the pathogen related proteins (PR), in special the PR1. Together with the npr1 gene, the genes npr3 and npr4 are also regulators of this system, regulating the action of the npr1 gene according to the levels of salicylic acid present in the cell, this level varies with the level of infection in each cell. Nevertheless, evaluating a citrus transgenic event may take several years. In order to shorten this time, model plants were used. The model chosen was the Micro-Tom tomato (Solanun lycopersicum L. cv. Micro-Tom). In order to obtain the genetic constructions, the genes Csnpr1, Csnpr3 e Csnpr4 were identified in Citrus sinensis L. Osbeck from the genes, Atnpr1, Atnpr3 and Atnpr4 present in the Arabidopsis thaliana L. genome. The citrus genes were obtained from the citrus genome using RT-PCR procedure and cloned separately into the pCambia 2201 vector, which was inserted into Agrobacterium tumefaciens in order to perform the genetic transformation. Sweet orange (Citrus sinensis L. Osbeck) and Micro-Tom plants were genetically modified. After the growth of the regenerated shoots, the evaluation of the obtained plants was done through PCR analysis. The genetically modified plants were acclimatized, the citrus plants were grafted and kept in the greenhouse, the Micro-Tom plants were propagated trough seeds and its progeny was evaluated by applying the selection antibiotic kanamycin, thus obtaining a homozygous transgenic line.

No description available.