Evaluation of the Chilli veinal mottle virus CP gene expressing transgenic Nicotiana benthamiana plants for disease resistance against the virus / Avaliação do gene CP do vírus Chilli veinal mottle que expressa plantas transgênicas Nicotiana benthamiana quanto à resistência a doenças contra o vírus

Vegetables are an important source of income and high-value crops for small farmers. Chilli (Capsicum spp.) is one of the most economically important vegetables of Pakistan and it is grown throughout the country. It is a rich source of nutrition especially vitamins A, B, C and E along with minerals as folic acid, manganese (Mn), potassium (K) and molybdenum (Mo). Chilli possesses seven times more amount of vitamin C than an orange. Vitamin A, C and betacarotenoids are strong antioxidants to scavenge the free radicals. Chilli production is restricted due to various biotic factors. Among these viruses, Chilli veinal mottle virus (ChiVMV) is one of the most destructive and menacing agents that inflicts heavy and colossal losses that accounted for 50% yield loss both in quality and quantity. Pathogen-Derived Resistance (PDR) approach is considered one of the effective approaches to manage plant viruses. In this study, ChiVMV was characterized on a molecular level, the coat protein (CP) gene of the virus was stably transformed into Nicotiana benthamiana plants using Agrobacterium tumefaciens. The transgenic plants were challenged with the virus to evaluate the level of resistance of plants against the virus. It was observed that the plants expressing CP gene have partial resistance against the virus in terms of symptoms' development and virus accumulation. Translation of this technique into elite chilli varieties will be resulted to mitigate the ChiVMV in the crop as well as an economic benefit to the farmers.

Vegetais são uma importante fonte de renda e culturas de alto valor para os pequenos agricultores. A pimenta-malagueta (Capsicum spp.) é uma das hortaliças mais importantes economicamente do Paquistão e é cultivada em todo o país. É uma rica fonte de nutrição, especialmente vitaminas A, B, C e E com minerais como ácido fólico, manganês (Mn), potássio (K) e molibdênio (Mo). O pimentão possui sete vezes mais vitamina C do que a laranja. Vitaminas A e C e betacarotenoides são antioxidantes fortes para eliminar os radicais livres. A produção de pimenta é restrita devido a vários fatores bióticos. Entre esses vírus, o ChiVMV é o agente mais destrutivo e ameaçador que inflige perdas pesadas e colossais que representam 50% da perda de rendimento, tanto em qualidade quanto em quantidade. A abordagem de resistência derivada de patógenos (PDR) é considerada uma das abordagens eficazes para gerenciar os vírus de plantas. Neste estudo, ChiVMV foi caracterizado em nível molecular e o gene CP do vírus foi transformado de forma estável em plantas Nicotiana benthamiana usando Agrobacterium tumefaciens. As plantas transgênicas foram desafiadas com o vírus para avaliar seu nível de resistência contra o vírus. Observou-se que as plantas que expressam o gene CP apresentam resistência parcial ao vírus em termos de desenvolvimento de sintomas e acúmulo de vírus. A tradução dessa técnica em variedades de pimenta de elite resultará na mitigação do ChiVMV na safra, bem como em benefícios econômicos para os agricultores em termos de melhor rendimento e baixo custo de produção.

Evaluation of the Chilli veinal mottle virus CP gene expressing transgenic Nicotiana benthamiana plants for disease resistance against the virus / Avaliação do gene CP do vírus Chilli veinal mottle que expressa plantas transgênicas Nicotiana benthamiana quanto à resistência a doenças contra o vírus

Vegetables are an important source of income and high-value crops for small farmers. Chilli (Capsicum spp.) is one of the most economically important vegetables of Pakistan and it is grown throughout the country. It is a rich source of nutrition especially vitamins A, B, C and E along with minerals as folic acid, manganese (Mn), potassium (K) and molybdenum (Mo). Chilli possesses seven times more amount of vitamin C than an orange. Vitamin A, C and beta carotenoids are strong antioxidants to scavenge the free radicals. Chilli production is restricted due to various biotic factors. Among these viruses, Chilli veinal mottle virus (ChiVMV) is one of the most destructive and menacing agents that inflicts heavy and colossal losses that accounted for 50% yield loss both in quality and quantity. Pathogen-Derived Resistance (PDR) approach is considered one of the effective approaches to manage plant viruses. In this study, ChiVMV was characterized on a molecular level, the coat protein (CP) gene of the virus was stably transformed into Nicotiana benthamiana plants using Agrobacterium tumefaciens. The transgenic plants were challenged with the virus to evaluate the level of resistance of plants against the virus. It was observed that the plants expressing CP gene have partial resistance against the virus in terms of symptoms' development and virus accumulation. Translation of this technique into elite chilli varieties will be resulted to mitigate the ChiVMV in the crop as well as an economic benefit to the farmers.

Vegetais são uma importante fonte de renda e culturas de alto valor para os pequenos agricultores. A pimenta-malagueta (Capsicum spp.) é uma das hortaliças mais importantes economicamente do Paquistão e é cultivada em todo o país. É uma rica fonte de nutrição, especialmente vitaminas A, B, C e E com minerais como ácido fólico, manganês (Mn), potássio (K) e molibdênio (Mo). O pimentão possui sete vezes mais vitamina C do que a laranja. Vitaminas A e C e betacarotenoides são antioxidantes fortes para eliminar os radicais livres. A produção de pimenta é restrita devido a vários fatores bióticos. Entre esses vírus, o ChiVMV é o agente mais destrutivo e ameaçador que inflige perdas pesadas e colossais que representam 50% da perda de rendimento, tanto em qualidade quanto em quantidade. A abordagem de resistência derivada de patógenos (PDR) é considerada uma das abordagens eficazes para gerenciar os vírus de plantas. Neste estudo, ChiVMV foi caracterizado em nível molecular e o gene CP do vírus foi transformado de forma estável em plantas Nicotiana benthamiana usando Agrobacterium tumefaciens. As plantas transgênicas foram desafiadas com o vírus para avaliar seu nível de resistência contra o vírus. Observou-se que as plantas que expressam o gene CP apresentam resistência parcial ao vírus em termos de desenvolvimento de sintomas e acúmulo de vírus. A tradução dessa técnica em variedades de pimenta de elite resultará na mitigação do ChiVMV na safra, bem como em benefícios econômicos para os agricultores em termos de melhor rendimento e baixo custo de produção.

Evaluation of the Chilli veinal mottle virus CP gene expressing transgenic Nicotiana benthamiana plants for disease resistance against the virus

Abstract Vegetables are an important source of income and high-value crops for small farmers. Chilli (Capsicum spp.) is one of the most economically important vegetables of Pakistan and it is grown throughout the country. It is a rich source of nutrition especially vitamins A, B, C and E along with minerals as folic acid, manganese (Mn), potassium (K) and molybdenum (Mo). Chilli possesses seven times more amount of vitamin C than an orange. Vitamin A, C and beta-carotenoids are strong antioxidants to scavenge the free radicals. Chilli production is restricted due to various biotic factors. Among these viruses, Chilli veinal mottle virus (ChiVMV) is one of the most destructive and menacing agents that inflicts heavy and colossal losses that accounted for 50% yield loss both in quality and quantity. Pathogen-Derived Resistance (PDR) approach is considered one of the effective approaches to manage plant viruses. In this study, ChiVMV was characterized on a molecular level, the coat protein (CP) gene of the virus was stably transformed into Nicotiana benthamiana plants using Agrobacterium tumefaciens. The transgenic plants were challenged with the virus to evaluate the level of resistance of plants against the virus. It was observed that the plants expressing CP gene have partial resistance against the virus in terms of symptoms development and virus accumulation. Translation of this technique into elite chilli varieties will be resulted to mitigate the ChiVMV in the crop as well as an economic benefit to the farmers.

Resumo Vegetais são uma importante fonte de renda e culturas de alto valor para os pequenos agricultores. A pimenta-malagueta (Capsicum spp.) é uma das hortaliças mais importantes economicamente do Paquistão e é cultivada em todo o país. É uma rica fonte de nutrição, especialmente vitaminas A, B, C e E com minerais como ácido fólico, manganês (Mn), potássio (K) e molibdênio (Mo). O pimentão possui sete vezes mais vitamina C do que a laranja. Vitaminas A e C e betacarotenoides são antioxidantes fortes para eliminar os radicais livres. A produção de pimenta é restrita devido a vários fatores bióticos. Entre esses vírus, o ChiVMV é o agente mais destrutivo e ameaçador que inflige perdas pesadas e colossais que representam 50% da perda de rendimento, tanto em qualidade quanto em quantidade. A abordagem de resistência derivada de patógenos (PDR) é considerada uma das abordagens eficazes para gerenciar os vírus de plantas. Neste estudo, ChiVMV foi caracterizado em nível molecular e o gene CP do vírus foi transformado de forma estável em plantas Nicotiana benthamiana usando Agrobacterium tumefaciens. As plantas transgênicas foram desafiadas com o vírus para avaliar seu nível de resistência contra o vírus. Observou-se que as plantas que expressam o gene CP apresentam resistência parcial ao vírus em termos de desenvolvimento de sintomas e acúmulo de vírus. A tradução dessa técnica em variedades de pimenta de elite resultará na mitigação do ChiVMV na safra, bem como em benefícios econômicos para os agricultores em termos de melhor rendimento e baixo custo de produção.

Biological parameters of Spodoptera cosmioides Walker (Lepidoptera: Noctuidae) in cotton varieties / Parâmetros biológicos de Spodoptera cosmioides Walker (Lepidoptera: Noctuidae) em variedades de algodoeiro

Spodoptera cosmioides Walker is a polyphagous insecticide-resistant species found in various regions of Brazil. Despite occurring at low densities, it is considered a potential pest of cotton, soybean, and bean crops in the Brazilian cerrado. This work investigated the comparative biology of S. cosmioides in the commercial transgenic cotton NuOPAL (Bollgard I, Evento 531) and the conventional isoline variety DeltaOPAL. The experiment was conducted under laboratory conditions (26 ± 1°C; relative humidity: 70 ± 10%; photoperiod: 12h), using newly-hatched and individualized larvae. We evaluated the duration and viability of immature stages, duration of the biological cycle, pupal weight, sex ratio, percentage of deformed adults and of adults trapped in the pupal case, adult longevity, fecundity, and egg viability. The biological parameters observed showed no significant differences between the two varieties studied, which enabled high consumption, high assimilation, high fecundity, and viability for S. cosmioides.(AU)

Spodoptera cosmioides Walker é uma espécie polífaga, resistente a inseticidas em várias regiões do país e, apesar de ocorrer em baixas densidades, é considerada uma praga potencial para as culturas de algodão, soja e feijão no cerrado. Neste trabalho, estudou-se a biologia comparada de S. cosmioides sobre o cultivar transgênico comercial de algodoeiro NuOPAL (Bollgard I, Evento 531) e sobre o cultivar isolinha convencional DeltaOPAL. O experimento foi desenvolvido em condições de laboratório (26 ± 1°C; UR: 70 ± 10%; fotofase: 12h) a partir de lagartas recém-eclodidas e individualizadas. Foram avaliados a duração e a viabilidade das fases imaturas, a duração do ciclo biológico, o peso de pupas, a razão sexual, a porcentagem de deformação de adultos e de adultos não liberados dos invólucros pupais, a longevidade de adultos, a fecundidade e viabilidade de ovos. Os parâmetros biológicos observados não diferiram significativamente em relação às duas cultivares, que proporcionaram alto consumo, alta assimilação, alta fecundidade e viabilidade à S. cosmioides.(AU)

Investigation of the response to salinity of transgenic potato plants overexpressing the transcription factor StERF94

Salinity is one of the most important constraints threatening the cultivation of potato plants (Solanum tuberosum L.). Itaffects plant growth and leads to significant yield loss. Consequently, it is important to improve the tolerance of potatoplants to salinity. In this context, we investigated the involvement of a potato ethylene responsive factor (StERF94) in plantresponse to salinity, since our previous genome-wide analysis showed that it may be related to biotic and abiotic stressresponse. ERF proteins belong to a large family of transcription factors that participate in plant response to abiotic stresses.We have previously identified the StERF94 gene which shows increased expression in potato plants submitted to salttreatment. In this study, transgenic potato plants overexpressing StERF94 were produced and submitted to salt treatment(100 mM NaCl) in vitro and under greenhouse culture conditions. StERF94 transgenic lines showed lower decrease of stemelongation under salt treatment in comparison to non-transgenic wild-type plants. Moreover, these plants showed a lowlevel of H2O2 and Malondialdehyde content, and an increase in catalase and GPX (Gluthation peroxidase) activitiescompared to non-transgenic plants. In a second step, enhanced expression of some target genes for example CuZn-SOD,DHN25 (Dehydrin) and ERD (Early Responsive to Dehydration) was noted in the StERF94 transgenic plants, submitted tosalt treatment. The StERF94 factor was also involved in the activation of osmoprotectant synthesis. Taken together, all thesedata suggest that overexpression of the StERF94 transcription factor increases the tolerance of potato plants to salinity byimproving plant growth, osmoprotectant synthesis and antioxidant activityleading to low oxidative stress damage.

Plant factory: new resource for the productivity and diversity of human and veterinary vaccines

Vaccination is one of the most successful strategies to prevent diseases caused by pathogens. Although various expression systems including Escherichia coli, yeast, insect, and mammalian cells are currently used for producing many of vaccines, these conventional platforms have the limitation of post-translational modification, high cost, and expensive scalability. In this respect, the plant-based expression system has been considered as an attractive platform to produce recombinant vaccines due to fast, cost-effective and scalable production as well as safety. This review discusses the development of plant-derived vaccines and the current stage of plant-based expression system.

Effect of soybean ureases on seed germination and plant development

Abstract Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide. The ammonia (nitrogen (N) product of urease activity) is incorporated into organic compounds. Thus, urease is involved in N remobilization, as well as in primary N assimilation. Two urease isoforms have been described for soybean: the embryo-specific, encoded by the Eu1 gene, and the ubiquitous urease, encoded by Eu4. A third urease-encoding gene was recently identified, designated Eu5, which encodes the putative protein product SBU-III. The present study aimed to evaluate the contribution of soybean ureases to seed germination and plant development. Analyses were performed using Eu1/Eu4/Eu5-co-suppressed transgenic plants and mutants of the Eu1 and Eu4 urease structural genes, as well as a urease-null mutant (eu3-a) that activates neither the ubiquitous nor embryo-specific ureases. The co-suppressed plants presented a developmental delay during the first month after germination; shoots and roots were significantly smaller and lighter. Slower development was observed for the double eu1-a/eu4-a mutant and the eu3-a single mutant. The N content in transgenic plants was significantly lower than in non-transgenic plants. Among the mutants, eu3-a presented the lowest and eu1-a the highest N content. Altogether, these results indicate that increased ureolytic activity plays an important role in plant development.

Expression of Hemagglutinin-Neuraminidase and fusion epitopes of Newcastle Disease Virus in transgenic tobacco

Background: Newcastle disease is an important avian infectious disease that brings about vast economic damage for poultry industry. Transgenic plants represent a cost-effective system for the production of therapeutic proteins and are widely used for the production of poultry vaccines. In an attempt to develop a recombinant vaccine, a plant expression binary vector pBI121, containing the genes encoding Hemagglutinin-Neuraminidase (HN) and Fusion (F) epitopes of Newcastle Disease Virus (NDV) under the control of CaMV35S promoter and NOS terminator was constructed and introduced into the tobacco ( Nicotiana tabacum) plant by Agrobacterium-mediated transformation. Results: Putative transgenic plants were screened in a selection medium containing 50 mg/L kanamycin and 30 mg/L meropenem. Integration of the foreign gene in plant genome was confirmed by PCR. Expression of foreign gene was analyzed at transcription level by RT-PCR and at translation level by means of dot blotting and ELISA. All analyses confirmed the expression of recombinant protein. Conclusion: Developments in genetic engineering have led to plant-based systems for recombinant vaccine production. In this research, tobacco plant was used to express F and HN epitopes of NDV. Our results indicate that for the production of recombinant vaccine, it is a novel strategy to use concatenated epitopes without their genetic fusion onto larger scaffold structure such as viral coat protein.

Utilization of genes encoding osmoprotectants in transgenic plants for enhanced abiotic stress tolerance

Global agriculture in the context of growing and expanding populations is under huge pressure to provide increased food, feed, and fiber. The recent phenomenon of climate change has further added fuel to the fire. It has been practically established now that the global temperature has been on the increase with associated fluctuations in annual rainfall regimes, and the resultant drought and flood events and increasing soil and water salinization. These challenges would be met with the introduction and utilization of new technologies coupled with conventional approaches. In recent years, transgenic technology has been proved very effective in terms of production of improved varieties of crop plants, resistant to biotic stresses. The abiotic stresses such as salt and drought are more complex traits, controlled by many genes. Transgenic plant development for these stresses has utilized many single genes. However, much emphasis has been placed on genes catalyzing the biosynthetic pathways of osmoprotectants. This review focuses on the current status of research on osmoprotectant genes and their role in abiotic stress tolerance in transgenic plants.

Chloroplast localization of Cry1Ac and Cry2A protein- an alternative way of insect control in cotton

BACKGROUND: Insects have developed resistance against Bt-transgenic plants. A multi-barrier defense system to weaken their resistance development is now necessary. One such approach is to use fusion protein genes to increase resistance in plants by introducing more Bt genes in combination. The locating the target protein at the point of insect attack will be more effective. It will not mean that the non-green parts of the plants are free of toxic proteins, but it will inflict more damage on the insects because they are at maximum activity in the green parts of plants. RESULTS: Successful cloning was achieved by the amplification of Cry2A, Cry1Ac, and a transit peptide. The appropriate polymerase chain reaction amplification and digested products confirmed that Cry1Ac and Cry2A were successfully cloned in the correct orientation. The appearance of a blue color in sections of infiltrated leaves after 72 hours confirmed the successful expression of the construct in the plant expression system. The overall transformation efficiency was calculated to be 0.7%. The amplification of Cry1Ac-Cry2A and Tp2 showed the successful integration of target genes into the genome of cotton plants. A maximum of 0.673 µg/g tissue of Cry1Ac and 0.568 µg/g tissue of Cry2A was observed in transgenic plants. We obtained 100% mortality in the target insect after 72 hours of feeding the 2nd instar larvae with transgenic plants. The appearance of a yellow color in transgenic cross sections, while absent in the control, through phase contrast microscopy indicated chloroplast localization of the target protein. CONCLUSION: Locating the target protein at the point of insect attack increases insect mortality when compared with that of other transgenic plants. The results of this study will also be of great value from a biosafety point of view.

Incorporation of Na+/H+ antiporter gene from Aeluropus littoralis confers salt tolerance in soybean (Glycine max L.).

To develop a salt-tolerant soybean (Glycine max L.) cultivar, a minimal linear Na+/H+ antiporter gene cassette (35S CaMV promoter, open-reading-frame of AlNHX1 from Aeluropus littoralis and NOS terminator) was successfully expressed in soybean cultivar TF-29. Southern and Northern blot analysis showed that AlNHX1 was successfully incorporated into the genome and expressed in the transgenic plants. The AlNHX1 transgenic plant lines exhibited improved growth in severe saline condition (150 mM NaCl). The transgenic lines accumulated a lower level of Na+ and a higher level of K+ in the leaves than wild-type plants under saline condition (150 mM NaCl). Observations on the chlorophyll content, photosynthetic rates, malondialdehyde and relative electrical conductivity indicated that transgenic plants exhibited tolerance to salt stress, growing normally at salt concentrations up to 150 mM. These results demonstrated that AlNHX1 was successfully transferred into soybean and the salt-tolerance was improved by the overexpression of AlNHX1.

Anomalias en los comienzos de la transgenesis vegetal: intereses e interpretaciones en torno a las primeras plantas transgenicas / Anomalies in the early stages of plant transgenesis: interests and interpretations surrounding the first transgenic plants

Se presentan los orígenes de la transgénesis vegetal, analizando los experimentos que llevaron a la obtención de las primeras plantas transgénicas. Aquí se entrecruzan actores, prácticas e intereses que resultan emblemáticos de la biotecnología. Se trata, además, de un caso donde se pone en juego el consenso sobre el sentido de experimentos fundamentales. Estos sucesos permiten ilustrar parte de los conflictos en los que se involucran los organismos genéticamente modificados, pues en torno a estos primeros experimentos los científicos articularán representaciones distintas sobre la transgénesis vegetal, valorando de un modo distinto las anomalías que presentaban los primeros experimentos. De este modo, se analizan los intereses e interpretaciones en torno a los primeros experimentos con plantas transgénicas.

The origins of plant transgenesis are discussed and the experiments that led to the first transgenic plants are analyzed. This process involved a series of actors, practices and interests specific to biotechnology. Consensus about the meaning of fundamental experiments was also at issue here. These events illustrate some of the conflicts related to genetically modified organisms, since scientists had different responses to plant transgenesis at the time of the first experiments, and opinions of the anomalies in those experiments varied. Thus, this article analyzes the interests and interpretations surrounding the first experiments involving transgenic plants.

Efficiency of phosphorus utilization in phyA-expressing cotton lines.

To evaluate and characterize the stability of traits conferred by phyA from Aspergillus ficuum, we examined expression of phyA in sexually-derived transgenic cotton progeny and assessed the capacity for phytate-utilization in T4 progeny. The gene (phyA) was expressed only in the roots, but not in the stem and leaf tissues. Phytase activity was 2.38-fold higher in transgenic line L2 than in wild-type (WT) plants. The amount of phosphorus in the leaves was also significantly higher in transgenic lines L2, L6 and L9. Among those lines, L2 performed best, showing increase in phosphorus contents of 10.67% (seedling stage), 8.78% (squaring), 11.77% (flowering) and 11.59% (boll-opening). The level of available phosphorus in the rhizosphere was 19% higher in soil containing transgenic plants compared with the WT. When both transgenic and WT were grown in the same type of soil, the number of bacteria, fungi and actinomycetes was not obviously different. These results indicated that although the T4 generation enhanced the utilization of phytate phosphorus, it had no influence on the number of soil microorganisms. Our findings also demonstrated that phytase-expression lines could be used for developing new varieties of cotton having improved phosphorus uptake from the soil.

Agrobacterium mediated biotransformation.

Twenty-five years ago, the concept of using Agrobacterium tumefaciens (soil gm-ve bacterium) as a vector to create transgenic plants (natural transformation) was viewed as a prospect and a “wish.” Transgenic plants generated by direct DNA transfer methods (e.g., polyethylene glycol or liposome-mediated transformation, electroporation, or particle bombardment) often integrate a large number of copies of the transgene in tandem or inverted repeat arrays, in either multiple or single loci. Genetically engineered corn, cotton and other crop plants have been produced whose genome contains a delta-endotoxin-coding region regulated by sequences. Hence the engineered plants produce the delta-endotoxin protein in their tissues, making them lethal when ingested by insects such as the europian corn borer, (that currently causes crop losses of field corn, popcorn, seedcorn and sweetcorn). From this some people feared that windborne pollen could dust many other plants and potentially harm beneficial insects such as butterflies and bees. Agrobacterium mediated transformed plants have economical and medicinal valuable products.

Genotypic variation of Agrobacterium-mediated transformation of Italian ryegrass

In the present study, genotypic variation of Agrobacterium-mediated transformation of Korean Italian ryegrass has been evaluated. Mature seed-derived calli of seven cultivars were inoculated and co-cultured with Agrobacterium tumefaciens carrying the binary vector pCAMBIA1301, which contains a reporter gene (gus) and a plant selectable marker gene conferring resistance to hygromycin (hpt) in the T-DNA region. The effects of several factors such as callus type and callus age on transformation effectiveness and the expression of the GUS gene were investigated. The highest transformation effectiveness (6.7 percent) was obtained with the Hwasan 101 cultivar when 9-week-old calli (type-I) were inoculated with Agrobacterium. The overall transformation rates of the examined cultivars ranged from 0.4 percent to 6.7 percent. GUS histochemical assays, PCR, and southern analysis of transgenic plants demonstrated that transgenes were successfully integrated into the genome of Italian ryegrass. Thus, evaluation of transformation effectiveness and selection of a suitable cultivar of Italian ryegrass may improve molecular breeding of this species.

REGENERACION Y SENSIBILIDAD A MANOSA EN ENTRENUDOS DE PAPA (Solanum tuberosum spp. andígena Var Diacol Capiro). / REGENERATION AND MANNOSE SENSIBILITY IN POTATO INTERNODAL EXPLANTS (Solanum tuberosum spp. andígena Var Diacol Capiro)

Se estableció un sistema de organogénesis indirecta para la obtención de brotes múltiples a partir de segmentos internodales de la variedad Diacol Capiro. La ubicación de explantes en medio Murashige y Skoog (MS) suplementado con 2 mg/l de zeatina ribosido (ZR), 0,02 mg/l de ácido naftalenácetico (ANA) y 0,02 mg/l de ácido giberélico (AG3), permite la obtención de plántulas entre la séptima y novena semana con una efectividad del 80-100%. Mediante ubicación de explantes previamente cocultivados con la cepa LBA4404 de Agrobacterium tumefaciens que contiene el plásmido recombinante pNOV022, se verificó la utilidad del medio para procesos de transformación, obteniéndose tasas hasta del 100% de regeneración. Finalmente, con el objetivo de determinar el uso potencial de la manosa como agente selectivo en procesos de transformación, se evaluó el efecto de diferentes concentraciones de manosa sobre la viabilidad y capacidad regenerativa de explantes.

A system of indirect organogenesis for the multiple buds production from internode stem sections in Diacol Capiro variety was established. Explants on Murashige & Skoog (MS) medium with zeatine riboside (ZR) 2 mg/l, naftalenacetic acid (NAA) 0.02 mg/l and giberelic acid (GA3) 0.02 mg/l, produced plants ranging between 7 to 9 weeks with 80-100% effectiveness. In the same medium, explants infected with Agrobacterium LBA4404 strain which carries recombinant plasmid pNOV022, produced regeneration rates reached 100%, thus, the medium utility for trnsformation processes was verified. Finally, to determine the potential use of the mannose as selective agent in transformation processes, the effect of different mannose concentrations on explant viability and regenerative capacity was evaluated.

Transgenic lettuce seedlings carrying hepatitis B virus antigen HBsAg

The obtainment of transgenic edible plants carrying recombinant antigens is a desired issue in search for economic alternatives viewing vaccine production. Here we report a strategy for genetic transformation of lettuce plants (Lactuca sativa L.) using the surface antigen HBsAg of hepatitis B virus. Transgenic lettuce seedlings were obtained through the application of a regulated balance of plant growth regulators. Genetic transformation process was acquired by cocultivation of cotyledons with Agrobacterium tumefaciens harboring the recombinant plasmid. It is the first description of a lettuce Brazilian variety "Vitória de Verão" genetically modified.

Transformação genética: estratégias e aplicações para o melhoramento genético de espécies florestais / Genetic transformation: strategies for forest species breeding

A transformação genética, que consiste na introdução controlada de um gene no genoma de uma célula receptora e em sua posterior expressão, assume adicional significância, pois abre novas perspectivas ao melhoramento genético de espécies florestais, disponibilizando novos genes com características desejáveis para serem incorporados em menor espaço de tempo. Através do uso de estratégias com Agrobacterium e biobalística, já foram obtidas plantas transgênicas com maior produção de biomassa, melhor qualidade de madeira, maior resistência a determinados insetos e com tolerância a herbicidas, entre outras características de interesse. Tais exemplos demonstram a relevância dessas ferramentas para o setor florestal. Esta revisão apresenta, de forma resumida, a importância do estabelecimento de um eficiente sistema de regeneração in vitro, as principais estratégias usadas na transformação genética de espécies florestais e algumas das características agroflorestais que já foram incorporadas nessas espécies.

The genetic transformation which consists in a controlled introduction of a gene in the genome of a receive cell and its subsequent expression, assumes additional significance, giving new perspectives to genetic improvement of the forest species, extending and available new genes with desirable characteristics, to be incorporated in a smaller period of time. Through the strategies Agrobacterium and bioballistic, transgenic plants had already been obtained showing higher biomass production, better wood quality, resistance to some insects, tolerance to herbicides, among other desirable characteristics, showing the relevance of these tools to the forest industry. This revision points out in a summarized way, the importance of establishing an efficient in vitro regeneration system, the strategies used in the genetic transformations of forestry species and some agroforestry characteristics that were previously incorporated in these species.

Genetic Engineering Progresses in Plant Resistance to Salt Stress / 中国生物工程杂志

Salinity is the main limitation factor for plant growth and crop production.Many approaches to enhance plant resistance to salinity by genetic engineering have been developed.Over-expressions of salt-tolerance related genes encoding proteins involved in signal transduction pathways,ion channels and compatible solutes synthesis for the stabilization of biological structures under salinity stress are the most often used strategies.The recent progresses in genetic engineering to improve salt tolerance in plants and the possible problems in researches was reviewed.

Antibacterial Cecropin and Its Application on Transgenic Plants for Bacterium Resistance / 中国生物工程杂志

Cecropin is a kind of heat-durable and broad-spectrum antibacterial polypeptides which has strong effect against bacteria,fungi,virus and some pathogenic microorganisms.Today Cecropin has been widely applied into plant genetic engineering,antiviral study,and inhibiting tumor cell proliferation.Its Structure-function relationship,antibacterial mechanism,and the application on transgenic plants for bacterium resistance was reviewed.Expression of Cecropin in plants has a great application potential in bacterium resistance.Deep analyses and research of molecular structure and action mechanism can promote the transgenic plants antibacterial research.