The plant hormone auxin regulates many aspects of plant growth and development. At the cellular level, auxin can stimulate cell division, cell elongation, and cell differentiation. Little is known about the molecular mechanisms that mediate auxin action at this level, although changes in gene expression have been implicated in each of them. An important step in elucidating the signal transduction steps involved in these responses is the identification of intermediates that respond to auxin treatment within a physiologically relevant range, and can be functionally linked to specific response(s). The Aux/IAA family of auxin-regulated genes, which has been identified in several species, may constitute such a group of signalling intermediates. This dissertation reports on the isolation and characterization of eleven tomato genes, LeIAA1 - 11, which are homologous to these Aux/IAA genes. Expression characteristics in response to exogenously-applied auxin were determined in segments of etiolated hypocotyls. The LeIAA genes fell into three kinetic classes and displayed differential responsiveness to the treatment. Comparison of auxin-induced expression in wild-type and the auxin-insensitive diageotropica (dgt) mutant revealed that induction of only a subset of genes was affected by the mutation while the other genes retained wild-type response levels in the mutant. This finding indicates that at least two signal transduction chains lead to auxin-induced gene expression, and the dgt gene product acts on only one of them. The expression pattern of nine LeIAA genes was determined in a wide variety of tissue samples in order to link individual LeIAA genes with specific physiological responses. To that end, a qualitative multiplex RT-PCR method was developed that allowed quick assessment of relative expression levels in a large number of small RNA samples. It was found that LeIAA10 expression was highest in tissues undergoing rapid growth, suggesting a role for this gene in the process of cell expansion. The expression of LeIAA1 1 was also variable during development, while LeIAA2 was strongly down-regulated after light treatment. These experiments demonstrated organ-preferential expression of LeIAA genes under the control of environmental factors and depending on developmental stages. The LeIAA genes may thus act as integrators of several other signals with the auxin stimulus. / Graduation date: 1998

Asymmetric localization of PIN proteins controls directionality of auxin transport and many aspects of plant development. The Arabidopsis mutant, unhinged-1 (unh-1), has defects to leaf veins and other root and shoot phenotypes. I identify UNH as the Arabidopsis VPS51 homologue, a member of the Arabidopsis GARP complex, and show that UNH interacts with VPS52, another member of the complex. I also show that UNH co-localizes with SYP61, a trans Golgi network marker. The GARP complex in yeast and metazoans retrieves vacuolar sorting receptors to the TGN and is important in sorting proteins for lysosomal degradation. PIN1 expression in the margin of unh-1 leaves is expanded and the unh leaf phenotype is suppressed by pin1 mutation, supporting the idea that the phenotype results from expanded PIN expression. My results suggest the UNH is important to restrict expression of PIN1 within the margin, likely by targeting PIN1 to the lytic vacuole. / xv, 100 leaves : ill. ; 29 cm

The complex vasculature seen in the vascular plants provides a scaffolding of structural support and is responsible for the movement of water, minerals, photosynthate and some hormones. The auxin canalization model proposes that a positive feedback mechanism causes auxin-transporting cells to become vascular cells. We have isolated a leaf-patterning mutant, unhinged (unh), which shows a simplified leaf vascular pattern with more freely ending veins and fewer secondary veins. Expression of the ATHB8::GUS reporter construct indicates that the UNH gene acts prior to procambial patterning of the first presumptive secondary veins. Expression of the auxin responsive reporter gene DR5::GUS is reduced in unh leaves and roots, indicating that UNH may be involved in auxin signaling. Increasing the level of auxin in unh leaves through the addition of auxin transport inhibitors, low concentrations of 2,4-dichlorophenoxyacetic acid, and through introducing unh into mutants in which auxin transport is defective partially rescues the unh phenotype, supporting this hypothesis. The unh mutation maps to a 60kb region near the top of chromosome IV. No other leaf vascular mutant or auxinassociated mutant have been reported in this area, thus UNH represents a novel component of leaf vascularization and auxin signaling. / xi, 65 leaves : ill. (some col.) ; 29 cm.

Auxin controls a range of growth related characteristics by a mechanism dependent upon polar auxin transport. We have identified a leaf vein patterning mutant that shows a simple first leaf vein pattern. The veins are often non-meeting and form somewhat parallel to one another. The leaves are narrow and pointed so that the overall leaf phenotype is reminiscent of grass leaves; hence the mutant name grassy (gsy). A range of shoot and root characteristics are also altered in gsy plants. Compared to wild type, gsy plants have shorter primary roots with reduced numbers of lateral roots and increased numbers of longer root hairs. Upon gravitropic stimulation, the root tip bends slightly away from the normal vector. As well, gsy plants produce an inflorescence with altered internode elongation and branching pattern. The intensity of the auxin responsive reporter gene DR5::GUS is unchanged in both roots and developing leaves of gsy, however, it shows subtle differences to the wild type DR5:GUS expression pattern. Finally, gsy leaf and root phenotypes are more sensitive to low doses of the auxin efflux inhibitor NPA and external auxin 2, 4-D. We suggest that this overall pattern is consistent with defects in auxin transport. / xii, 76 leaves : ill. ; 29 cm.

Orientador: Fábio Tebaldi Silveira Nogueira / Banca: Luiz Fernando Rolim de Almeida / Banca: Michel Georges Abert Vizentz / Resumo: Os MicroRNAs (miRNAs) são pequenos RNAs endógenos não codantes de 20-22 nucleotídeos (nt) que regulam a expressão gênica de genes-alvos. Eles estão envolvidos em diversos aspectos de desenvolvimento da planta, tanto na parte aérea, quanto no sistema radicular. Os miRNAs e seus genesalvos tem uma complementariedade quase perfeita em plantas, sendo que esta complementaridade está relacionada à origem dos genes de miRNAs (genes MIRs). A hipótese mais aceita para a origem dos genes de miRNAs é a "hipótese de duplicação invertida", a qual propõe que os genes de miRNAs surgiram a partir de duplicações invertidas do seus genes-alvos nos genomas vegetais. Muitos genes-alvos de miRNA em plantas codificam para fatores de transcrição, tais como os genes SQUAMOSA Promoter-Binding Protein-Like (SPLs). Alguns membros da família SPL são regulados por ambos os miRNAs, miR156 e miR529. O sítio de reconhecimento destes microRNAs em transcritos de genes SPLs é conservado e difere somente por sete nucleotídeos. Enquanto o miR156 é altamente conservado entre Angiospermas, incluindo arabidopsis, o miR529 aparentemente está presente somente em eudicotiledôneas basais, monocotiledôneas e no musgo Physcomitrella patens. Neste trabalho, foram realizadas duas abordagens para o estudo da via miRNAs/SPL. Na primeira abordagem, foi analisada a evolução e a possível função da via miR529/SPL em monocotiledôneas e eudicotiledôneas. Foi testado o sítio de reconhecimento do miR529b em dois genes SPLs (SPL9 e SPL15) de arabidopsis encontrados bioinformaticamente via geração de plantas transgênicas de arabidopsis superexpressando o precursor de arroz OsMIR529b. As linhagens transgênicas de arabidopsis (OsMIR529b-OE) apresentaram fenótipos vegetativos e reprodutivos similares aos de plantas duplo mutantes de perda de função para os genes SPL9 e SPL15 de arabidopsis (denominado spl9/spl15). Estes ... / Abstract: MicroRNAs (miRNAs) are endogenous small non-coding RNAs of 20-22 nucleotides (nt) in length that regulate the gene expression transcriptionally and posttranscriptionally. They are involved in many aspects of plant development, both in the shoot and in the root systems. MiRNAs and their target genes have an almost perfect complementarily in plants, and this is related to the complementarity of genes origin of miRNAs genes (MIR genes). The most accepted hypothesis for the origin of miRNA genes is the "inverted duplication hypothesis," which proposes that genes of miRNAs arose from inverted duplications of their target genes in plant genomes. Many miRNA target genes in plants encode transcription factors such as SQUAMOSA Promoter-Binding Protein-Like (SPLs). Some SPL family members SPL are regulated by both miRNAs, miR156 and miR529. The recognition site for these microRNAs in SPL transcripts is conserved and only differs by seven nucleotides. While miR156 is highly conserved among Angiosperms, including Arabidopsis thaliana, miR529 is apparently present only in basal eudicots, monocots and in the moss Physcomitrella patens. In this work, were performed two approaches to study miRNA-direct SPL gene regulation. In the first approach, we analyzed the evolution and possible function of the miR529/SPL pathway in monocots and eudicotyledonous. We searched for miR529b recognition sites in SPL genes from core eudicots, such as Arabidopsis thaliana. Interestingly, we found two miR529b-targeted SPLs (SPL9 and SPL15) in Arabidopsis and showed that the recognition sites are functional via the generation of transgenic Arabidopsis plants overexpressing OsMIR529b. OsMIR529b-OE overpressors are phenotipically and molecularly similar to the double mutant spl9/spl15. Our data suggest that miR529b is processed and functional in core eudicots and that this microRNA was recently lost in the evolutionary history of the ... / Mestre

The plant hormone auxin is involved in a wide range of developmental phenomena in plants. It carries out many of its effects through a signalling network involving the regulation of specific genes, including those involved in its own polar transport between cells. These transporters are able to be redistributed between cell faces, causing the asymmetric auxin transport that is a key requirement for the formation of vein patterns in leaves. In this thesis I describe the development of a biochemical kinetics-based model of auxin signalling and transport in a single cell, which displays biologically plausible responses to auxin application. The single-cell model then serves as the basis for a multicell model of auxin-mediated vein formation at a very early stage of leaf formation in Arabidopsis thaliana. / ix, 73 leaves : ill. ; 29 cm.

Made available in DSpace on 2014-06-11T19:26:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-19Bitstream added on 2014-06-13T20:53:55Z : No. of bitstreams: 1 000749212.pdf: 2326147 bytes, checksum: b30560592085048dea18f80f7e336ca1 (MD5) / Os MicroRNAs (miRNAs) são pequenos RNAs endógenos não codantes de 20-22 nucleotídeos (nt) que regulam a expressão gênica de genes-alvos. Eles estão envolvidos em diversos aspectos de desenvolvimento da planta, tanto na parte aérea, quanto no sistema radicular. Os miRNAs e seus genesalvos tem uma complementariedade quase perfeita em plantas, sendo que esta complementaridade está relacionada à origem dos genes de miRNAs (genes MIRs). A hipótese mais aceita para a origem dos genes de miRNAs é a “hipótese de duplicação invertida”, a qual propõe que os genes de miRNAs surgiram a partir de duplicações invertidas do seus genes-alvos nos genomas vegetais. Muitos genes-alvos de miRNA em plantas codificam para fatores de transcrição, tais como os genes SQUAMOSA Promoter-Binding Protein-Like (SPLs). Alguns membros da família SPL são regulados por ambos os miRNAs, miR156 e miR529. O sítio de reconhecimento destes microRNAs em transcritos de genes SPLs é conservado e difere somente por sete nucleotídeos. Enquanto o miR156 é altamente conservado entre Angiospermas, incluindo arabidopsis, o miR529 aparentemente está presente somente em eudicotiledôneas basais, monocotiledôneas e no musgo Physcomitrella patens. Neste trabalho, foram realizadas duas abordagens para o estudo da via miRNAs/SPL. Na primeira abordagem, foi analisada a evolução e a possível função da via miR529/SPL em monocotiledôneas e eudicotiledôneas. Foi testado o sítio de reconhecimento do miR529b em dois genes SPLs (SPL9 e SPL15) de arabidopsis encontrados bioinformaticamente via geração de plantas transgênicas de arabidopsis superexpressando o precursor de arroz OsMIR529b. As linhagens transgênicas de arabidopsis (OsMIR529b-OE) apresentaram fenótipos vegetativos e reprodutivos similares aos de plantas duplo mutantes de perda de função para os genes SPL9 e SPL15 de arabidopsis (denominado spl9/spl15). Estes... / MicroRNAs (miRNAs) are endogenous small non-coding RNAs of 20-22 nucleotides (nt) in length that regulate the gene expression transcriptionally and posttranscriptionally. They are involved in many aspects of plant development, both in the shoot and in the root systems. MiRNAs and their target genes have an almost perfect complementarily in plants, and this is related to the complementarity of genes origin of miRNAs genes (MIR genes). The most accepted hypothesis for the origin of miRNA genes is the inverted duplication hypothesis, which proposes that genes of miRNAs arose from inverted duplications of their target genes in plant genomes. Many miRNA target genes in plants encode transcription factors such as SQUAMOSA Promoter-Binding Protein-Like (SPLs). Some SPL family members SPL are regulated by both miRNAs, miR156 and miR529. The recognition site for these microRNAs in SPL transcripts is conserved and only differs by seven nucleotides. While miR156 is highly conserved among Angiosperms, including Arabidopsis thaliana, miR529 is apparently present only in basal eudicots, monocots and in the moss Physcomitrella patens. In this work, were performed two approaches to study miRNA-direct SPL gene regulation. In the first approach, we analyzed the evolution and possible function of the miR529/SPL pathway in monocots and eudicotyledonous. We searched for miR529b recognition sites in SPL genes from core eudicots, such as Arabidopsis thaliana. Interestingly, we found two miR529b-targeted SPLs (SPL9 and SPL15) in Arabidopsis and showed that the recognition sites are functional via the generation of transgenic Arabidopsis plants overexpressing OsMIR529b. OsMIR529b-OE overpressors are phenotipically and molecularly similar to the double mutant spl9/spl15. Our data suggest that miR529b is processed and functional in core eudicots and that this microRNA was recently lost in the evolutionary history of the ...

O acamamento de plantas provoca perdas significativas no rendimento de grãos da cultura da soja e por isso estratégias de manejo para minimizar o acamamento são importante necessidade na agricultura atual. O objetivo desse trabalho foi estudar ação de reguladores de crescimento vegetal sobre o acamamento e outras características agronômicas da cultivar de soja CD 214 RR, em épocas de semeadura e densidades distintas. Foram conduzidos dois experimentos na Estação Experimental da Universidade Tecnológica Federal do Paraná, Campus Pato Branco. No primeiro experimento foram testados diferentes reguladores de crescimento, sob concentrações distintas. O delineamento experimental foi inteiramente ao acaso com trinta e um tratamentos e quatro repetições. As quatro melhores combinações de reguladores/concentrações neste experimento foram utilizadas no segundo experimento. O segundo experimento foi conduzido em delineamento experimental de blocos ao acaso, com 3 repetições, em um esquema fatorial 5x3x3, em que o primeiro fator correspondeu às quatro combinações de reguladores/concentrações selecionadas no primeiro experimento e, também, a testemunha sem aplicação; o segundo fator correspondeu a três diferentes épocas de semeadura (01 de novembro, 15 de novembro, e 11 de dezembro); o terceiro fator correspondeu a três diferentes densidades de semeadura, em que a população final para cada densidade foi de 200.000, 300.000 e 400.000 plantas ha-1. No primeiro experimento, foram avaliados o acamamento, injúria e estatura de planta, durante o desenvolvimento da cultura. No segundo experimento também foram avaliadas estas variáveis, somente ao final do ciclo da cultura. No primeiro experimento foram coletadas amostras de plantas em 0,45 m2, na área útil da parcela, para posterior determinação dos componentes do rendimento, no estádio R9. Uma amostra foi coletada no estádio R8, representada por 10 plantas por parcela, em que foi obtido o índice de colheita e rendimento biológico aparente. Em ambos os experimentos, no estádio R9 da cultura, houve a colheita do restante da área útil da parcela, para determinação do rendimento de grãos. Os dados obtidos foram submetidos à análise de variância pelo teste F e foram comparados através de testes de comparação de médias. A relação entre variáveis dependentes e independentes foi ajustada através de regressão polinomial. Todos os tratamentos, de todos os seis grupos de reguladors vegetais foram eficientes em controlar o acamamento durante a maior parte do ciclo da cultura. O grupo do precursor de etileno ocasionou maior grau de fitotoxidade à cultura. Os compostos inibidores de auxina, inibidores de protox e bioestimulantes (AIB, GA3 e cinetina) apresentaram bons resultados na redução de estatura e do acamamento, apresentando grau de fitotoxidade leve e rápida recuperação dos sintomas de injúria. Os reguladores trinexapac ethyl (312,5 g ha-1), IBA+GA3+cinetina (0,0375+0,0375+0,0675 g ha-¹) e lactofen (144 g ha-1) resultaram em rendimento de grãos mais elevados. Isoladamente, as três concentrações de ethephon estudadas apresentam menor número de vagens por planta, menor peso de grão e menor rendimento de grãos. Os efeitos de fitorreguladores sobre o rendimento de grãos e componentes foram dependentes dos níveis em que estes foram aplicados sobre as plantas de soja. Onze tratamentos perfizeram o grupo que apresentou os rendimento de grãos mais elevados, entre eles os compostos por trinexapac ethyl (312,5 g ha-1), IBA+GA3+cinetina (0,0375+0,0375+0,0675 g ha-1) e lactofen (144 g ha-1). Entre todos os tratamentos, três concentrações de ethephon estudadas apresentam menor número de vagens por planta, menor peso de grão e menor rendimento de grãos. O lactofen (144 g ha-1) promoveu maior redução em estatura, em plantas semeadas na primeira (01/11/08) e terceira época (11/12/08). Já o cloreto de mepiquat (250 g ha-1)foi mais eficaz na redução de estatura de plantas da terceira época de semeadura (11/12/08). O menor acamamento ocorreu na segunda época de semeadura, na densidade de 200.000 plantas ha-1. Considerando-se a média de densidades e épocas de semeadura, os reguladores TIBA (6 g ha-¹), lactofen (144 g ha-¹) e AIB+GA3+Cinetina (0,0375+0,0375+0,0675 g ha-¹) apresentaram o melhor desempenho na redução do acamamento. O maior rendimento de grãos de soja ocorreu na semeadura de 11 de dezembro, não sendo influenciado pela densidade de plantas nesta época. O menor rendimento de grãos em soja ocorreu na semeadura do início de novembro, na densidade de 400.000 plantas ha-1. No segundo experimento, as plantas de todos os tratamentos com regulador de crescimento não apresentaram sintoma de injúria na avaliação realizada no estádio R1 da cultura. / The lodging of plants causes significant losses in grain yield of soybean and therefore management strategies to minimize the lodging are important in agriculture today. The aim of this work was to study the action of reducers of plant growth on lodging and other agronomic characteristics of soybean CD 214 RR at sowing dates and different densities. Two experiments were conducted at the Experimental Station of the Federal Technological University of Paraná, Pato Branco Campus. In the first experiment, testing different reducers of growth under different concentrations. The experimental design was completely andomized thirty-one treatments and four replicates. The four best combinations of concentrations in this experiment were used in the second experiment. The second experiment was conducted in a randomized block design with 3 replicates in a 5x3x3 factorial design, where the first factor corresponding to four combinations of concentrations selected in the first experiment (and also the control), the second factor corresponded to three different sowing dates (01 November, 15 November, and December 11), the third factor corresponded to three different plant densities in the final population for each density was 200.000, 300.000 and 400.000 plants ha-1. The first experiment examined the lodging, injury and plant height during the development of the culture. In the second experiment also evaluated these variables at the end of the cycle. In the first experiment samples were collected from plants in 0,45 m2 in each parcel, for later determination of yield components, the stage R9. A sample was collected at the R8 stage, represented by 10 plants per plot, which was obtained harvest index and biological yield apparent. In both experiments, the R9 stage of culture, there was the harvest of the remainder of each parcel to determine the yield. The data were subjected to analysis of variance by F test and were compared by means of comparison tests of means. The relationship between dependent and independent variables was adjusted by polynomial regression. All treatments in all six groups retardant were efficient in controlling the lodging for most of the crop cycle. The precursor of ethylene group caused a greater degree of phytotoxicity to the crop. The compounds of auxin inhibitors, protox and biostimulators (IBA, GA3 and kinetin) were able to reduce height and lodging, with slight degree of phytotoxicity and with rapid recovery of symptoms injury. Reducers trinexapac ethyl (312.5 g ha-1), IBA +GA3 +kinetin (0.0375, 0.0375 and 0.0675 g ha-¹) and lactofen (144 g ha-1) resulted in yield higher. Individually, the three concentrations of ethephon studied have a lower number of pods per plant, lower weight and lower grain yield. The effects of growth regulators on yield and components were dependent on the levels at which they are applied on the soybean plants. Eleven treatments accounted for the group the higher yield, among them the trinexapac ethyl (312.5 g ha-1), IBA GA3 kinetin (0.0375, 0.0375 and 0.0675 g ha-¹) and lactofen (144 g ha-1). Among all the treatments, the plants that received the three concentrations of ethephon studied have a lower number of pods per plant, lower weight and lower grain yield. The lactofen (144 g ha- 1) provided greater reduction in height, plants sown in the first (01/11/08) and third time (11/12/08). Since the chloride doses (250 g ha-1) was more effective in reducing plant height of the third sowing date (11/12/08). Smallest lodging occurred in the second sowing date, density of 200.000 plants ha-1. Considering the average densities and sowing dates, regulators TIBA (6 g ha-1), lactofen (144 g ha-1) and IBA +GA3+Kinetin (0.0375+0.0375+0.0675 g ha-1) showed the best performance in reducing lodging. The highest yield of soybean at sowing occurred on December 11 and is not influenced by the density of plants at this time. The lower yield in soybean planting occurred in early November, with a density of 400.000 plants ha-1. In the second experiment, plants of all treatments with growth retardant had no symptoms of injury in the assessment at the R1 stage of culture.

O acamamento de plantas provoca perdas significativas no rendimento de grãos da cultura da soja e por isso estratégias de manejo para minimizar o acamamento são importante necessidade na agricultura atual. O objetivo desse trabalho foi estudar ação de reguladores de crescimento vegetal sobre o acamamento e outras características agronômicas da cultivar de soja CD 214 RR, em épocas de semeadura e densidades distintas. Foram conduzidos dois experimentos na Estação Experimental da Universidade Tecnológica Federal do Paraná, Campus Pato Branco. No primeiro experimento foram testados diferentes reguladores de crescimento, sob concentrações distintas. O delineamento experimental foi inteiramente ao acaso com trinta e um tratamentos e quatro repetições. As quatro melhores combinações de reguladores/concentrações neste experimento foram utilizadas no segundo experimento. O segundo experimento foi conduzido em delineamento experimental de blocos ao acaso, com 3 repetições, em um esquema fatorial 5x3x3, em que o primeiro fator correspondeu às quatro combinações de reguladores/concentrações selecionadas no primeiro experimento e, também, a testemunha sem aplicação; o segundo fator correspondeu a três diferentes épocas de semeadura (01 de novembro, 15 de novembro, e 11 de dezembro); o terceiro fator correspondeu a três diferentes densidades de semeadura, em que a população final para cada densidade foi de 200.000, 300.000 e 400.000 plantas ha-1. No primeiro experimento, foram avaliados o acamamento, injúria e estatura de planta, durante o desenvolvimento da cultura. No segundo experimento também foram avaliadas estas variáveis, somente ao final do ciclo da cultura. No primeiro experimento foram coletadas amostras de plantas em 0,45 m2, na área útil da parcela, para posterior determinação dos componentes do rendimento, no estádio R9. Uma amostra foi coletada no estádio R8, representada por 10 plantas por parcela, em que foi obtido o índice de colheita e rendimento biológico aparente. Em ambos os experimentos, no estádio R9 da cultura, houve a colheita do restante da área útil da parcela, para determinação do rendimento de grãos. Os dados obtidos foram submetidos à análise de variância pelo teste F e foram comparados através de testes de comparação de médias. A relação entre variáveis dependentes e independentes foi ajustada através de regressão polinomial. Todos os tratamentos, de todos os seis grupos de reguladors vegetais foram eficientes em controlar o acamamento durante a maior parte do ciclo da cultura. O grupo do precursor de etileno ocasionou maior grau de fitotoxidade à cultura. Os compostos inibidores de auxina, inibidores de protox e bioestimulantes (AIB, GA3 e cinetina) apresentaram bons resultados na redução de estatura e do acamamento, apresentando grau de fitotoxidade leve e rápida recuperação dos sintomas de injúria. Os reguladores trinexapac ethyl (312,5 g ha-1), IBA+GA3+cinetina (0,0375+0,0375+0,0675 g ha-¹) e lactofen (144 g ha-1) resultaram em rendimento de grãos mais elevados. Isoladamente, as três concentrações de ethephon estudadas apresentam menor número de vagens por planta, menor peso de grão e menor rendimento de grãos. Os efeitos de fitorreguladores sobre o rendimento de grãos e componentes foram dependentes dos níveis em que estes foram aplicados sobre as plantas de soja. Onze tratamentos perfizeram o grupo que apresentou os rendimento de grãos mais elevados, entre eles os compostos por trinexapac ethyl (312,5 g ha-1), IBA+GA3+cinetina (0,0375+0,0375+0,0675 g ha-1) e lactofen (144 g ha-1). Entre todos os tratamentos, três concentrações de ethephon estudadas apresentam menor número de vagens por planta, menor peso de grão e menor rendimento de grãos. O lactofen (144 g ha-1) promoveu maior redução em estatura, em plantas semeadas na primeira (01/11/08) e terceira época (11/12/08). Já o cloreto de mepiquat (250 g ha-1)foi mais eficaz na redução de estatura de plantas da terceira época de semeadura (11/12/08). O menor acamamento ocorreu na segunda época de semeadura, na densidade de 200.000 plantas ha-1. Considerando-se a média de densidades e épocas de semeadura, os reguladores TIBA (6 g ha-¹), lactofen (144 g ha-¹) e AIB+GA3+Cinetina (0,0375+0,0375+0,0675 g ha-¹) apresentaram o melhor desempenho na redução do acamamento. O maior rendimento de grãos de soja ocorreu na semeadura de 11 de dezembro, não sendo influenciado pela densidade de plantas nesta época. O menor rendimento de grãos em soja ocorreu na semeadura do início de novembro, na densidade de 400.000 plantas ha-1. No segundo experimento, as plantas de todos os tratamentos com regulador de crescimento não apresentaram sintoma de injúria na avaliação realizada no estádio R1 da cultura. / The lodging of plants causes significant losses in grain yield of soybean and therefore management strategies to minimize the lodging are important in agriculture today. The aim of this work was to study the action of reducers of plant growth on lodging and other agronomic characteristics of soybean CD 214 RR at sowing dates and different densities. Two experiments were conducted at the Experimental Station of the Federal Technological University of Paraná, Pato Branco Campus. In the first experiment, testing different reducers of growth under different concentrations. The experimental design was completely andomized thirty-one treatments and four replicates. The four best combinations of concentrations in this experiment were used in the second experiment. The second experiment was conducted in a randomized block design with 3 replicates in a 5x3x3 factorial design, where the first factor corresponding to four combinations of concentrations selected in the first experiment (and also the control), the second factor corresponded to three different sowing dates (01 November, 15 November, and December 11), the third factor corresponded to three different plant densities in the final population for each density was 200.000, 300.000 and 400.000 plants ha-1. The first experiment examined the lodging, injury and plant height during the development of the culture. In the second experiment also evaluated these variables at the end of the cycle. In the first experiment samples were collected from plants in 0,45 m2 in each parcel, for later determination of yield components, the stage R9. A sample was collected at the R8 stage, represented by 10 plants per plot, which was obtained harvest index and biological yield apparent. In both experiments, the R9 stage of culture, there was the harvest of the remainder of each parcel to determine the yield. The data were subjected to analysis of variance by F test and were compared by means of comparison tests of means. The relationship between dependent and independent variables was adjusted by polynomial regression. All treatments in all six groups retardant were efficient in controlling the lodging for most of the crop cycle. The precursor of ethylene group caused a greater degree of phytotoxicity to the crop. The compounds of auxin inhibitors, protox and biostimulators (IBA, GA3 and kinetin) were able to reduce height and lodging, with slight degree of phytotoxicity and with rapid recovery of symptoms injury. Reducers trinexapac ethyl (312.5 g ha-1), IBA +GA3 +kinetin (0.0375, 0.0375 and 0.0675 g ha-¹) and lactofen (144 g ha-1) resulted in yield higher. Individually, the three concentrations of ethephon studied have a lower number of pods per plant, lower weight and lower grain yield. The effects of growth regulators on yield and components were dependent on the levels at which they are applied on the soybean plants. Eleven treatments accounted for the group the higher yield, among them the trinexapac ethyl (312.5 g ha-1), IBA GA3 kinetin (0.0375, 0.0375 and 0.0675 g ha-¹) and lactofen (144 g ha-1). Among all the treatments, the plants that received the three concentrations of ethephon studied have a lower number of pods per plant, lower weight and lower grain yield. The lactofen (144 g ha- 1) provided greater reduction in height, plants sown in the first (01/11/08) and third time (11/12/08). Since the chloride doses (250 g ha-1) was more effective in reducing plant height of the third sowing date (11/12/08). Smallest lodging occurred in the second sowing date, density of 200.000 plants ha-1. Considering the average densities and sowing dates, regulators TIBA (6 g ha-1), lactofen (144 g ha-1) and IBA +GA3+Kinetin (0.0375+0.0375+0.0675 g ha-1) showed the best performance in reducing lodging. The highest yield of soybean at sowing occurred on December 11 and is not influenced by the density of plants at this time. The lower yield in soybean planting occurred in early November, with a density of 400.000 plants ha-1. In the second experiment, plants of all treatments with growth retardant had no symptoms of injury in the assessment at the R1 stage of culture.

Orientador: José Camillo Novello / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-22T19:34:56Z (GMT). No. of bitstreams: 1 Gomes_FabianaHelenaForte_M.pdf: 6688953 bytes, checksum: ffe979c84bdddab601e6a550b2872ebb (MD5) Previous issue date: 2013 / Resumo: O Brasil é o maior produtor de citros no mundo, entretanto, várias doenças ameaçam a citricultura brasileira, dentre elas o cancro cítrico, causado pela bactéria Xanthomonas citri subsp. citri (Xcc). A doença é caracterizada por necrose e lesões eruptivas. Sabe-se que a bactéria transloca proteínas efetoras para o interior da célula hospedeira e modula a transcrição na planta. Dentre as proteínas translocadas está à proteína PthA que por si só é capaz de induzir hiperplasia e hipertrofia tecidual. Em relação aos genes cuja expressão foi induzida pela infecção por X. citri estão àqueles envolvidos na remodelação da parede celular, síntese, mobilização e sinalização de auxina e giberelina, os quais são os principais hormônios vegetais controladores de crescimento celular. Corroborando com isso, tanto auxina como giberelina ativam a expressão de celulases e expansinas e são necessárias para o desenvolvimento do cancro cítrico. Em 2010 demonstrou-se a interação entre PthAs e a proteína ARF ("auxin response fator") de Citrus sinensis (CsARF), um possível repressor da via de auxina. O promotor do gene da expansina de citros (CsEXP), cujo gene foi induzido por X. citri e auxina contêm uma sequência similar aos chamados AuxRe, elementos cis-regulatórios de resposta à auxina, localizado adjacentemente ao provável TATA-"box". Sendo assim, analisou-se a região 5' a montante do gene CsEXP de C. sinensis a fim de saber se este representa de fato o promotor mínimo do gene e se o "box AuxRE-like" funciona como elemento regulatório de resposta à auxina. No ensaio de transformação de CsEXP para ativação do gene repórter GUS, a região promotora foi responsiva à auxina, havendo, portanto uma regulação positiva do gene pelo hormônio. Há uma interação (sinergismo) entre a proteína PthA2 e/ou PthA4 com auxina na regulação da transcrição. Esta região que contém o "box AuxRE-like" possui uma sequência TGTCTA a qual está justaposta ao possível TATA-box no promotor do gene podendo se tratar de uma região de provável co-interação entre as duas proteínas. As proteínas CsARF e PthA2, em ensaios gel "shift", demonstraram afinidade por esta região, o que corrobora com a hipótese de co-interação nessa região. Os resultados demonstram que esta região do DNA mostra se como importante alvo de estudo, envolvendo interações correlacionadas com o desenvolvimento da doença / Abstract: Brazil is the biggest in the world in the citrus production, but many diseases threaten the Brazilian citrus cultivation, among them the citric canker, a disease characterized by hyperplastic lesions on the host surface, having Xanthomonas citri subsp. citri (Xcc) as the causal agent of citrus canker. It is known that the bacterium translocates effector proteins into the host cell to modulate transcription in the plant, including the PthA protein which itself is capable of inducing tissue hyperplasia and hypertrophy. Recently, it was shown that X. citri induces the expression of genes involved in cell wall remodeling, synthesis, mobilization and signaling of auxin and gibberellic acid, main plant hormones controlling cell growth and division. Furthermore, auxin and gibberellin are capable to activate the expression of cellulases and expansins and both of them are necessary for the development of citrus canker. Moreover, we verified the interaction between PthA and the protein ARF (auxin response factor) of Citrus sinensis (CsARF), and that promoter of the gene of expansins citrus (CsExp) it was induced by X. citri and auxin, which contains a sequence similar to known AuxRe, cis-regulatory elements in response to auxin, located adjacent to the probable TATA-box. Therefore, we analyzed the 5' region upstream of the gene CsExp of C. sinensis in order to know if in fact represents the minimal promoter of the gene and if AuxRE-box-like functions as regulatory element in response to auxin._ In the test transformation of CsEXP for activating GUS, the promoter region was responsive to auxin, the results were promising, because the minimal promoter of the gene was responsive to auxin in vivo assays, which have confirmed the activation of the reporter gene by auxin, with therefore an upregulation of the gene by the hormone. There is a synergy between the proteins PthA2 and PthA4 with auxin in the regulation. This region contains the AuxRE-like-box which has a sequence TGTCTA which is juxtaposed to the potential TATA-box within the promoter of the gene, possibly being a region of likely joint-interaction for the two proteins._PthA2 and CsARF Proteins in gel shift tests demonstrated affinity for this region, which could confirms the hypothesis of the region to be a region of jointinteraction. The results were significant and this region of the DNA shown to be an important target for study of interactions likely correlated with the development of the disease / Mestrado / Bioquimica / Mestra em Biologia Funcional e Molecular