No description available.

Plant transformation provides a promising methodology of introducing new genes that encode desirable traits to a wide range of crop plants. Success in genetic transformation has been achieved in many of the important crop species, such as soybean, cotton, rice, corn. However, wheat, one of the major crops of the world, has been considered to be difficult to transform via either Agrobacterium or biolistic bombardment (Rakszegi et al., 2001). There have been limited studies on A. tumefaciens-mediated transformation of cereals, including wheat, because of the overall refractory character of host-pathogen interactions between Agrobacterium and the cereal plants (Gould et al., 1991; Hiei et al., 1994; Cheng et al., 1997). While the genetic transformation of rice using Agrobacterium has become routine, only a few successful studies of Agrobacterium- mediated transformation of wheat have been reported, and these involved a model spring wheat, Triticum aestivum cultivar Bobwhite (Cheng et al., 1997). Model genotypes are developed for ease of plant regeneration in tissue culture and both Agrobacterium and biolistic mediated transformation methods require regeneration of plants in tissue culture. More success has been achieved in obtaining fertile transgenic wheat plants by particle bombardment, or biolistics method (Vasil et al., 1992; Weeks et al., 1993; Becker et al., 1994; Zhou et al., 1995; Altpeter et al., 1996). Wheat plants of the model system cultivar Bobwhite were used in most of these studies as well. The primary objective of this study was to use the callus-based transformation procedures mentioned above with a non-model cultivar of hexaploid spring wheat Saratovskaya-29, widely grown in Kazakhstan, to test the genotype dependence of the previously developed transformation protocols with respect to stable transfer of DNA and regeneration of transgenic plants. The spring wheat cultivar Saratovskaya-29 (Albidum-24/ Lutescens-55-11) was chosen for the study as being one of the most widely grown wheat cultivars both in Russia and Kazakhstan. It was bred in early 50??s in the Research Institute of the South-East, Saratov. Because of its drought resistance and good baking quality traits, Saratovskaya-29 reached a peak of nearly 21.2 mln ha in the former USSR in 1996 (Martynov and Dobrotvorskaya, 1996). Economical importance of this cultivar makes it an appropriate candidate for further improvement of economically significant traits. Another objective of the study described was to compare the transformation efficiencies and inheritance in the transgenic plants produced.

The aim of this work was to determine whether there are besides morphogenetic and metabolomic changes in viroid-infected plants also some alterations in the expression of transcription factors (TFs) known from our previous work to be involved in the secondary metabolites production, namely HlMyb1, HlMyb3, HlbHLH, HlbZIPA and HlbZIP2 TFs. Infectious vectors were prepared containing dimers of two closely related viroids- hop stunt viroid (HSVd) and cucumber pale fruit viroid (CPFVd). To achieve infection of hop (Humulus lupulus L.), biolistic inoculation of young shoots was performed. Hop cv. Admiral was chosen as a model for our experiments, because of its high flavonoid content in leaves. Infection of hop with both of these viroid species was proven by means of Northern hybridization and dot-blot techniques. Plants infected with HSVd showed serious symptoms such as stunted growth, epinasty and rugosity of leaves. Interestingly, decoloration of the petioles of the plants infected with HSVd was observed, maybe as a result of lower anthocyanins production. These symptoms were similar but milder in CPFVd-infected hops. On plants bearing symptoms, HPLC analyses were performed and compared to controls to detect changes in the levels of flavonol glycosides, phenolic acids, bitter acids and xanthohumol. In HSVd-infected hop leaves and petioles, significant decrease in the contents of flavonol glycosides and phenolic acids was observed. On the other hand, an increase in the amount of xanthohumol and bitter acids was detected in HSVd-infected tissues compared to healthy controls. Unlike to HSVd infection, the decrease of all analyzed secondary metabolites was observed in CPFVd-infected material. This difference suggests an alternative response of metabolome pathways to CPFVd-caused pathogenesis in comparison to HSVd. Semiquantitative RT PCR was performed to assay levels of TFs in healthy and infected hop tissues. Quantitative RealTime analyses of putative hop transcription factors HlbZIPA and HlbZIP2 were carried out using RNA isolated from HSVd-infected petioles. Increased mRNA levels of bZIP TFs were detected in infected material, suggesting an involvement of these factors in the response of the host plants to HSVd infection. Using thermodynamic methods of TGGE and heteroduplex analysis, several sequence variants of HlbZIP2 were idetified. According to aminoacid sequence alignment, this putative factor belongs to a group of bZIP proteins known for ABA/stress signalling in A. thaliana.

Dendritic spines are small protrusions that receive 90% of excitatory cortical synapses and are critically important to neural function. Each dendritic spine is supported by a dynamic actin cytoskeleton that responds to internal and external cues to allow spine development, elongation, retraction and movement. Multiple proteins have roles in spinogenesis, but until now, a regulatory role for actin itself has not been established. Here, we show that, in the acute slice preparation, actin expression increases during a period of rapid spinogenesis. Furthermore, actin overexpression in organotypic hippocampal cultures leads to a significant increase in spine density on CA1 pyramidal cells. Specifically, the number of filopodia (long, thin protrusions without heads) increases by 38% on secondary apical dendrites and 88% on basal dendrites and the number of elongated spines with heads increases by 162% on secondary apical dendrites and 113% on basal dendrites. Synapsin-I immunostaining demonstrated that the majority of filopodia and elongated spines are apposed by axon terminals. Additionally, we show that overexpressed actin enters both new and established spines within 24 h. These data demonstrate that neurons undertaking spinogenesis upregulate actin expression, that actin overexpression per se increases spine density, and that both new and established spines incorporate exogenous actin.

No description available.

A cana-de-açúcar vem assumindo um papel de destaque na atual conjuntura nacional, impulsionada principalmente pela produção de etanol, que vai de encontro com a crescente preocupação mundial na busca por fontes de energias renováveis e menos impactantes ao ambiente. Por essa razão, é preciso assegurar o contínuo desenvolvimento técnico-científico do setor sucroalcooleiro nacional, mantendo o Brasil na posição de vanguarda na produção de biocombustíveis. Ante a disponibilidade de inúmeras ferramentas biotecnológicas, tornou-se possível avançar com maior celeridade na compreensão dos campos da genética e fisiologia da cana-de-açúcar. Neste trabalho é demonstrado a transformação genética via biobalística da cultivar RB835486. No processo foram usadas duas construções para silenciamento gênico via RNA de interferência (RNAi), com genes quiméricos do tipo shRNA (short harpin RNA) para silenciamento dos genes SspTIP1;1 e SspPIP1;4, em co-tranformação com o gene marcador npt- II. Os dois genes alvo selecionados codificam aquaporinas, proteínas transmembrana responsáveis pelo transporte de água na planta. Estes genes foram identificados anteriormente por seu possível envolvimento no processo de acúmulo de sacarose. A co-integração dos cassetes de silenciamento gênico e do gene marcador ocorreu em 13 plantas, sendo obtidas três linhagens para o gene SspTIP1;1 e 10 linhagens para o gene SspPIP1;4. Dentre elas, duas linhagens SspTIP1;1 e cinco linhagens SspPIP1;4 foram analisadas via RT-PCR, quanto a possíveis modificações nos níveis de expressão dos genes alvos. Nas duas linhagens transgênicas avaliadas para silenciamento do SspTIP1;1, não houve redução em sua expressão em relação ao controle não transformado, possivelmente devido a efeitos de posição. Nas outras cinco linhagens transgênicas avaliadas para silenciamento do SspPIP1;4, houve redução significativa em seus níveis de expressão em três linhagens em relação ao controle não transformado. Nestas plantas serão realizadas as análises fisiológicas a fim de validá-las funcionalmente quanto ao transporte de água e acúmulo de sacarose. / Sugarcane has taken a leading role in the current national economy, mainly boosted by ethanol production, which meet the growing global concern on searching for renewable energy and with low impact on the environment. Therefore, it is necessary to ensure the continuous technical and scientific development of the national sugar and ethanol sector, maintaining the leading position of Brazil in biofuel production. By the availability of numerous biotechnology tools, it became possible to advance more rapidly in understanding the fields of genetics and physiology of sugarcane. This work demonstrated the genetic transformation of the cultivar RB835486 via biolistic assay. In the process it was used two constructs for gene silencing via RNA interference (RNAi) with chimeric genes of the type shRNA (short harpin RNA) for silencing of the genes SspTIP1;1 and SspPIP1;4, co-transformed with the marker gene npt- II. The two selected target genes encode aquaporins, transmembrane proteins which are responsible for water transport in plants. These genes were previously identified for their possible involvement in the process of sucrose accumulation. The co-integration of both, the cassette gene silencing and gene marker was observed in 13 plants, three strains were obtained for the gene SspTIP1;1 and 10 strains for gene SspPIP1;4. Among them, two strains of SspTIP1;1 and five strains of SspPIP1;4 were analyzed by RT-PCR, searching for possible changes in the levels of target gene expression. In the two transgenic lines evaluated for silencing SspTIP1;1, no reduction in expression compared to control non-transformed was obtained, possibly due to effects of position insertion of the gene in the genome. The other five transgenic lines evaluated for silencing of SspPIP1;4, a significant reduction in their expression levels was obtained in three strains when compared to the control untransformed plants. These silenced plants will be physiologically analyzed to validate their function on water transport and sucrose accumulation.

Made available in DSpace on 2016-06-24T04:00:22Z (GMT). No. of bitstreams: 1 Sergio Araujo Figueiredo.pdf: 5051471 bytes, checksum: 845523d46a114f99e92e4c1f07b80e2a (MD5) Previous issue date: 2011-06-03 / ß-galactosidases are a class of glycosyl-hydrolases that act on the plant cell primary walls, hydrolyzing ß-D-galactose at the nonreducing ends of ß-D-galactosides present in several biological molecules. Initially a characterization of the monosaccharides present in the primary wall of the pericarp and endosperm of Coffea arabica fruits at different ripening stages was performed, identifying the polysaccharides present in these regions, along with the putative carbohydrate target for the ß-galactosidase. In parallel, a molecular and a biochemical characterization of ß-galactosidase was performed. A partial characterization of ß-galactosidase genomic DNA structure, along with a transcription analysis and an in vitro and in situ biochemical activity were performed, identifying peaks of expression in the early stages of growth and in fully ripe fruit. Finally, in order to evaluate the ß-galactosidase effects on coffee fruit ripening, C. arabica calli were transformed by biolistic using RNA interference approach, in order to obtain genetically modified coffee plants with a silenced ß-galactosidase expression. Three transgenic calli growing on selective medium containing ammonium glufosinate were obtained, two of which contained the ß-galactosidase gene fragment. These calli are under embryogenic regeneration and the resulting seedlings will be further analyzed in order to confirm the presence of the transgenes and to assess of the effects of ß-galactosidase gene silencing on coffee fruit ripening. / As ß-galactosidases sao uma classe de glicosil-hidrolases que atuam na parede primaria das celulas vegetais, hidrolisando residuos ß-D-galactosis de extremidades nao redutoras de ß-D galactosideos presentes em diversas moleculas biologicas. Inicialmente foi feita uma caracterizacao dos monossacarideos presentes na parede primaria do pericarpo e do endosperma de frutos de Coffea arabica em distintas fases de maturacao, identificando os polissacarideos presentes nesta regiao celular, juntamente com os provaveis carboidratos-alvo para as ß-galactosidases. Em paralelo, foi realizada uma caracterizacao molecular e bioquimica das ß-galactosidases. Foi realizada uma caracterização parcial da estrutura do seu DNA genomico, juntamente com uma analise do nivel de transcricao e da atividade bioquimica in vitro e in situ foram realizadas, identificando picos de expressao nas fases iniciais de crescimento e nos frutos completamente maduros. Por fim, visando avaliar os efeitos das ß-galactosidases na maturacao de frutos de cafe, calos embriogenicos de C. arabica foram transformados por biobalistica, utilizando a tecnica do RNA interferente, com a finalidade de obtencao de plantas geneticamente modificadas de cafeeiro para o silenciamento da expressao do gene das ß-galactosidases. Foram obtidos tres calos transgenicos crescendo em meio seletivo com glufosinato de amonio, dentre os quais dois continham o fragmento deste gene. Estes calos encontram-se em fase de formacao de embrioes somaticos e as plantulas resultantes desta regeneracao serao analisadas, a posteriori, para confirmacao da presenca dos transgenes e avaliacao dos efeitos do silenciamento do gene das ß-galactosidases sobre a maturacao de frutos de cafe.

O Brasil é o principal produtor de maracujá amarelo. Entretanto, a produtividade é baixa, cerca de 1 0.000 t por hectare. A produção de frutos varia com o cultivar, condições climáticas, manejo e outros fatores, principalmente doenças causadas por bactérias e vírus. Metodologias de transformação genética são alternativas modernas para obter plantas resistentes. A proteína derivada de inseto, atacina A atua como bactericida, e tem sido utilizada para conferir resistência a espécies vegetais. Os objetivos do presente estudo foram (i) obter a regeneração de brotos in vitro, (ii) testar a eficiência de agentes seletivos durante o processo organogênico, (iii) construir o cassete contendo o gene atacína A, e (iv) determinar as condições físicas e biológicas para a transformação genética de plantas de maracujá amarelo utilizando o método de biobaiística. Em relação a estudos in vitro, três recipientes de cultura foram avaliados como também diferentes concentrações de benzylaminopurina (BA) e água de coco que foram adicionadas ao meio basal. Phytagei e agar também foram testados como agentes solidificantes. As culturas foram avaliadas quanto à resposta morfogênica dos discos foliares. O gene atacina A foi sequenciado e clonado para receber o promotor CAMV 35S com um enhancer duplicado e o terminador 35S. Este vetor foi denominado pFFatacina. O cassete de expressão foi cionado nos vetores pcambia 1300 e pcambia 2300 que contêm os genes higromicina (hpt) e canamicina (nptll), respectivamente. Discos foliares, assim como segmentos entrenodais e hipocotiledonares que induzem calos, foram usados nos experimentos de biobaiística. A expressão do gene uida foi avaliada para testar os parâmetros de bombardeamento, pressão de gás Hélio (psi) e a distância da tela de retenção até o tecido alvo (cm). A resposta organogênica dos discos foliares não diferiu quando placas de petrí, tubos ou frascos foram usados, embora os tubos (2,4 x 8,5 cm, 30 mi) mostraram uma resposta ligeiramente melhor. O meio MS (Murashige & Skoog, Physiologia Plantarum, 15, 1962) solidificado com agar (0,6%) e suplementado com 0,5 mg/L BA e 5% de água de coco (w/v) provou ser eficiente na indução de organgênese. Brotos foram obtidos após 30 dias. Segmentos entrenodais e hipocotiledonares produziram 300 estruturas semelhantes a gemas por explante. Microscopia de varredura e análises histológicas demonstraram ser estruturas foliares, as quais evoluíram em brotos após 50 dias em Y2 MS. Higromicina a 5 mg/L provou ser um agente seletivo apropdado, inibindo organogênese em 60% dos explantes. Canamicina a 50 mg/L foi também efetiva. Calos morfogênicos de até 10 dias e discos foliares de 3 dias de cultivo mostraram elevados níveis de expressão transiente sob 80016,5 ou 100019,5 (psi de gás Héliolcm de distância de võo dos microprojéteis). Foram realizados experimentos de co-transformação com pB[426 (8,7 kb) que contém o gene npdi e pFFatacina (5,25 kb), como também utilizando-se um único vetor (pcatacina 1300), Freqüência de transformação estável de 0,85% foi obtida. A integração do transgene foi confirmada por PCR para o gene atacina A. Este é o primeiro trabalho que relata a transferência de um gene de interesse para plantas de maracujá amarelo por biobalística. / Brazil is the leading producer of the yellow passion fruit. However, the productivity is fairly low, about 10,000 t per hectare. Fruit yields vary with cultivars, climatic conditions, management and other factors, namely bacterial and virus díseases. Genetic transformation methodologies are modern alternatives to obtain plant resistance. The insectderived protein, attacin A acts as bacterícide, and it has been used to confer resistance to plant species. The objectives of the present study were (i) to obtain in vitro shoot regeneration, (ii) to test the efficiency of certain selective agents during the organogenesis process, (iií) to construct the cassette containing the attacin A gene, and (iv) to determine the physical and biological conditions for genetic transformation of passion fruit plants by using the biolistic approach. Regarding the ín vítro studies, three culture recipients were evaluated as well as different concentrations of benzylaminopurine (BA) and coconut water that suppiemented the basal medium. Phytagei and agar were aiso tested as solidifying agents. Cultures were evaluated with respect to leaf dises morphogenic responses. The attacín A gene was sequenced, and cioned to receive the CAMV 35S promoter with a duplicated enhancer sequence, and the 35S terminator. This vector was denoted pFFatacina. The cassette was cioned in pcambia 1300 and pcambia 2300 vectors that contain the hygromícin (hpt) and kanamycin (nptil) genes, respectively. Leaf discs, as well as internodal segments and hypocotyl-derived sections chosen to índuce calii, were used in the biolistic experiments. The uida gene expression was evaluated for testing bombardment parameters, namely the helium pressure (psi) and the distance from the stopping screen to the target tissue (cm). The organogenic response of the leaf discs did not differ when petri dishes, tubes or culture vesseis were used although the tubes (2,4 x 8,5 cm, 30 ml capacity) showed to be slightly better. The agar (0.6%)-solidifíed MS (Murashige & Skoog, Physíología Plantarum, 15, 1962) medium suppiemented with 0.5 mg/L BA and 5% (wlv) coconut water proved to be efficient to induce organogenesis. Shoots were obtained after 30 days. Internada[ and hypocotyl-derived segments produced 300 bud-like structures per explant. Scanning microscopy and histologícal anaiyses provided evidences that they were leaf structures, which last 50 days in 1/2 MS to evolve into shoots. Hygromicin at 5 mg/L proved to be proper as selective agent, inhibiting organogenesis in 60% of the explants. Kanamycin at 50 mg/L was also effective. Morphogenic calli up to 10 days old and 3 d-leaf discs showed high levels of transient uida gene expression under 80016.5 or 1000/9.5 helium pressureldistance from the stopping screen to the target tissue. Cotransformation experiments with pBI426 (8.7 kb) that contain the nptil gene and pFFatacina (5.25 kb) were carried on as well singre vector transformation tríals (pcatacina 1300). Stable transformation frequency of 0.85% was obtained. Transgene integration was confirmei by PCR for the attacin A gene. This is the first report on agronomicaily useful-gene transfer to yeilow passion fruit plants by biolistics.

A cana-de-açúcar vem assumindo um papel de destaque na atual conjuntura nacional, impulsionada principalmente pela produção de etanol, que vai de encontro com a crescente preocupação mundial na busca por fontes de energias renováveis e menos impactantes ao ambiente. Por essa razão, é preciso assegurar o contínuo desenvolvimento técnico-científico do setor sucroalcooleiro nacional, mantendo o Brasil na posição de vanguarda na produção de biocombustíveis. Ante a disponibilidade de inúmeras ferramentas biotecnológicas, tornou-se possível avançar com maior celeridade na compreensão dos campos da genética e fisiologia da cana-de-açúcar. Neste trabalho é demonstrado a transformação genética via biobalística da cultivar RB835486. No processo foram usadas duas construções para silenciamento gênico via RNA de interferência (RNAi), com genes quiméricos do tipo shRNA (short harpin RNA) para silenciamento dos genes SspTIP1;1 e SspPIP1;4, em co-tranformação com o gene marcador npt- II. Os dois genes alvo selecionados codificam aquaporinas, proteínas transmembrana responsáveis pelo transporte de água na planta. Estes genes foram identificados anteriormente por seu possível envolvimento no processo de acúmulo de sacarose. A co-integração dos cassetes de silenciamento gênico e do gene marcador ocorreu em 13 plantas, sendo obtidas três linhagens para o gene SspTIP1;1 e 10 linhagens para o gene SspPIP1;4. Dentre elas, duas linhagens SspTIP1;1 e cinco linhagens SspPIP1;4 foram analisadas via RT-PCR, quanto a possíveis modificações nos níveis de expressão dos genes alvos. Nas duas linhagens transgênicas avaliadas para silenciamento do SspTIP1;1, não houve redução em sua expressão em relação ao controle não transformado, possivelmente devido a efeitos de posição. Nas outras cinco linhagens transgênicas avaliadas para silenciamento do SspPIP1;4, houve redução significativa em seus níveis de expressão em três linhagens em relação ao controle não transformado. Nestas plantas serão realizadas as análises fisiológicas a fim de validá-las funcionalmente quanto ao transporte de água e acúmulo de sacarose. / Sugarcane has taken a leading role in the current national economy, mainly boosted by ethanol production, which meet the growing global concern on searching for renewable energy and with low impact on the environment. Therefore, it is necessary to ensure the continuous technical and scientific development of the national sugar and ethanol sector, maintaining the leading position of Brazil in biofuel production. By the availability of numerous biotechnology tools, it became possible to advance more rapidly in understanding the fields of genetics and physiology of sugarcane. This work demonstrated the genetic transformation of the cultivar RB835486 via biolistic assay. In the process it was used two constructs for gene silencing via RNA interference (RNAi) with chimeric genes of the type shRNA (short harpin RNA) for silencing of the genes SspTIP1;1 and SspPIP1;4, co-transformed with the marker gene npt- II. The two selected target genes encode aquaporins, transmembrane proteins which are responsible for water transport in plants. These genes were previously identified for their possible involvement in the process of sucrose accumulation. The co-integration of both, the cassette gene silencing and gene marker was observed in 13 plants, three strains were obtained for the gene SspTIP1;1 and 10 strains for gene SspPIP1;4. Among them, two strains of SspTIP1;1 and five strains of SspPIP1;4 were analyzed by RT-PCR, searching for possible changes in the levels of target gene expression. In the two transgenic lines evaluated for silencing SspTIP1;1, no reduction in expression compared to control non-transformed was obtained, possibly due to effects of position insertion of the gene in the genome. The other five transgenic lines evaluated for silencing of SspPIP1;4, a significant reduction in their expression levels was obtained in three strains when compared to the control untransformed plants. These silenced plants will be physiologically analyzed to validate their function on water transport and sucrose accumulation.

O Brasil é o principal produtor de maracujá amarelo. Entretanto, a produtividade é baixa, cerca de 1 0.000 t por hectare. A produção de frutos varia com o cultivar, condições climáticas, manejo e outros fatores, principalmente doenças causadas por bactérias e vírus. Metodologias de transformação genética são alternativas modernas para obter plantas resistentes. A proteína derivada de inseto, atacina A atua como bactericida, e tem sido utilizada para conferir resistência a espécies vegetais. Os objetivos do presente estudo foram (i) obter a regeneração de brotos in vitro, (ii) testar a eficiência de agentes seletivos durante o processo organogênico, (iii) construir o cassete contendo o gene atacína A, e (iv) determinar as condições físicas e biológicas para a transformação genética de plantas de maracujá amarelo utilizando o método de biobaiística. Em relação a estudos in vitro, três recipientes de cultura foram avaliados como também diferentes concentrações de benzylaminopurina (BA) e água de coco que foram adicionadas ao meio basal. Phytagei e agar também foram testados como agentes solidificantes. As culturas foram avaliadas quanto à resposta morfogênica dos discos foliares. O gene atacina A foi sequenciado e clonado para receber o promotor CAMV 35S com um enhancer duplicado e o terminador 35S. Este vetor foi denominado pFFatacina. O cassete de expressão foi cionado nos vetores pcambia 1300 e pcambia 2300 que contêm os genes higromicina (hpt) e canamicina (nptll), respectivamente. Discos foliares, assim como segmentos entrenodais e hipocotiledonares que induzem calos, foram usados nos experimentos de biobaiística. A expressão do gene uida foi avaliada para testar os parâmetros de bombardeamento, pressão de gás Hélio (psi) e a distância da tela de retenção até o tecido alvo (cm). A resposta organogênica dos discos foliares não diferiu quando placas de petrí, tubos ou frascos foram usados, embora os tubos (2,4 x 8,5 cm, 30 mi) mostraram uma resposta ligeiramente melhor. O meio MS (Murashige & Skoog, Physiologia Plantarum, 15, 1962) solidificado com agar (0,6%) e suplementado com 0,5 mg/L BA e 5% de água de coco (w/v) provou ser eficiente na indução de organgênese. Brotos foram obtidos após 30 dias. Segmentos entrenodais e hipocotiledonares produziram 300 estruturas semelhantes a gemas por explante. Microscopia de varredura e análises histológicas demonstraram ser estruturas foliares, as quais evoluíram em brotos após 50 dias em Y2 MS. Higromicina a 5 mg/L provou ser um agente seletivo apropdado, inibindo organogênese em 60% dos explantes. Canamicina a 50 mg/L foi também efetiva. Calos morfogênicos de até 10 dias e discos foliares de 3 dias de cultivo mostraram elevados níveis de expressão transiente sob 80016,5 ou 100019,5 (psi de gás Héliolcm de distância de võo dos microprojéteis). Foram realizados experimentos de co-transformação com pB[426 (8,7 kb) que contém o gene npdi e pFFatacina (5,25 kb), como também utilizando-se um único vetor (pcatacina 1300), Freqüência de transformação estável de 0,85% foi obtida. A integração do transgene foi confirmada por PCR para o gene atacina A. Este é o primeiro trabalho que relata a transferência de um gene de interesse para plantas de maracujá amarelo por biobalística. / Brazil is the leading producer of the yellow passion fruit. However, the productivity is fairly low, about 10,000 t per hectare. Fruit yields vary with cultivars, climatic conditions, management and other factors, namely bacterial and virus díseases. Genetic transformation methodologies are modern alternatives to obtain plant resistance. The insectderived protein, attacin A acts as bacterícide, and it has been used to confer resistance to plant species. The objectives of the present study were (i) to obtain in vitro shoot regeneration, (ii) to test the efficiency of certain selective agents during the organogenesis process, (iií) to construct the cassette containing the attacin A gene, and (iv) to determine the physical and biological conditions for genetic transformation of passion fruit plants by using the biolistic approach. Regarding the ín vítro studies, three culture recipients were evaluated as well as different concentrations of benzylaminopurine (BA) and coconut water that suppiemented the basal medium. Phytagei and agar were aiso tested as solidifying agents. Cultures were evaluated with respect to leaf dises morphogenic responses. The attacín A gene was sequenced, and cioned to receive the CAMV 35S promoter with a duplicated enhancer sequence, and the 35S terminator. This vector was denoted pFFatacina. The cassette was cioned in pcambia 1300 and pcambia 2300 vectors that contain the hygromícin (hpt) and kanamycin (nptil) genes, respectively. Leaf discs, as well as internodal segments and hypocotyl-derived sections chosen to índuce calii, were used in the biolistic experiments. The uida gene expression was evaluated for testing bombardment parameters, namely the helium pressure (psi) and the distance from the stopping screen to the target tissue (cm). The organogenic response of the leaf discs did not differ when petri dishes, tubes or culture vesseis were used although the tubes (2,4 x 8,5 cm, 30 ml capacity) showed to be slightly better. The agar (0.6%)-solidifíed MS (Murashige & Skoog, Physíología Plantarum, 15, 1962) medium suppiemented with 0.5 mg/L BA and 5% (wlv) coconut water proved to be efficient to induce organogenesis. Shoots were obtained after 30 days. Internada[ and hypocotyl-derived segments produced 300 bud-like structures per explant. Scanning microscopy and histologícal anaiyses provided evidences that they were leaf structures, which last 50 days in 1/2 MS to evolve into shoots. Hygromicin at 5 mg/L proved to be proper as selective agent, inhibiting organogenesis in 60% of the explants. Kanamycin at 50 mg/L was also effective. Morphogenic calli up to 10 days old and 3 d-leaf discs showed high levels of transient uida gene expression under 80016.5 or 1000/9.5 helium pressureldistance from the stopping screen to the target tissue. Cotransformation experiments with pBI426 (8.7 kb) that contain the nptil gene and pFFatacina (5.25 kb) were carried on as well singre vector transformation tríals (pcatacina 1300). Stable transformation frequency of 0.85% was obtained. Transgene integration was confirmei by PCR for the attacin A gene. This is the first report on agronomicaily useful-gene transfer to yeilow passion fruit plants by biolistics.