In order to discover genes expressed in leaves of Musa acuminata ssp. burmannicoides var. Calcutta 4 (AA), from plants submitted to temperature stress, we produced and characterized two full-length enriched cDNA libraries. Total RNA from plants subjected to temperatures ranging from 5°C to 25°C and from 25°C to 45°C was used to produce a COLD and a HOT cDNA library, respectively. We sequenced 1,440 clones from each library. Following quality analysis and vector trimming, we assembled 2,286 sequences from both libraries into 1,019 putative transcripts, consisting of 217 clusters and 802 singletons, which we denoted Musa acuminata assembled expressed sequence tagged (EST) sequences (MaAES). Of these MaAES, 22.87% showed no matches with existing sequences in public databases. A global analysis of the MaAES data set indicated that 10% of the sequenced cDNAs are present in both cDNA libraries, while 42% and 48% are present only in the COLD or in the HOT libraries, respectively. Annotation of the MaAES data set categorized them into 22 functional classes. Of the 2,286 high-quality sequences, 715 (31.28%) originated from full-length cDNA clones and resulted in a set of 149 genes.
The introduction of anti-apoptotic genes into plants leads to resistance to environmental stress and broad-spectrum disease resistance. The anti-apoptotic gene (p35) from a baculovirus was introduced into the genome of passion fruit plants by biobalistics. Eleven regenerated plants showed the presence of the p35 gene by PCR and/or dot blot hybridization. Transcriptional analysis of regenerated plants showed the presence of specific p35 transcripts in 9 of them. Regenerated plants containing the p35 gene were inoculated with the cowpea aphid-borne mosaic virus (CABMV), the bacterium Xanthomonas axonopodis pv passiflorae, and the herbicide, glufosinate, (Syngenta). None of the plants showed resistance to CABMV. Regenerated plants (p35+) showed less than half of local lesions showed by non-transgenic plants when inoculated with X. axonopodis and some p35+ plants showed increased tolerance to the glufosinate herbicide when compared to non-transgenic plants.
Improving the quality and performance of soybean oil as biodiesel depends on the chemical composition of its fatty acids and requires an increase in monounsaturated acids and a reduction in polyunsaturated acids. Despite its current use as a source of biofuel, soybean oil contains an average of 25 % oleic acid and 13 % palmitic acid, which negatively impacts its oxidative stability and freezing point, causing a high rate of nitrogen oxide emission. Gas chromatography and ion mobility mass spectrometry were conducted on soybean fatty acids from metabolically engineered seed extracts to determine the nature of the structural oleic and palmitic acids. The soybean genes FAD2-1 and FatB were placed under the control of the 35SCaMV constitutive promoter, introduced to soybean embryonic axes by particle bombardment and down-regulated using RNA interference technology. Results indicate that the metabolically engineered plants exhibited a significant increase in oleic acid (up to 94.58 %) and a reduction in palmitic acid (to <3 %) in their seed oil content. No structural differences were observed between the fatty acids of the transgenic and non-transgenic oil extracts.
O mamoeiro (Carica papaya L.) e a videira (Vitis vinifera L.) destacam-se entre as fruteiras produzidas no Brasil por serem plantadas em quase todo o território nacional e apresentarem importância econômica e social. A tecnologia de produção de organismos geneticamente modificados, também conhecidos como "transgênicos", tem grande potencial de uso no desenvolvimento de fruteiras melhoradas. Porém, questões de propriedade intelectual limitam o uso da engenharia genética por países em desenvolvimento, que normalmente não detêm direitos sobre processos ou produtos necessários ao uso desta. Neste contexto, o presente estudo buscou avaliar promotores de expressão gênica alternativos ao CaMV 35S, que é o mais utilizado no desenvolvimento de transgênicos, mas é patenteado. Para tanto, construções gênicas com o gene gus sob a regulação de diferentes promotores foram testadas para expressão transiente em diversos tecidos de mamoeiro e videira. Expressão transiente foi avaliada em embriões somáticos, folhas, caules, raízes e frutos. O promotor do gene UBQ3, que é constitutivo e se encontra em domínio publico, mostrou ser uma alternativa promissora para futuros trabalhos de transformação genética de mamoeiro, mas não de videira.
RESUMO -Questões relacionadas à biossegurança de organismos geneticamente modificados e à percepção pública destes têm levado as instituições envolvidas no desenvolvimento comercial de plantas transgênicas a abandonarem o uso de genes marcadores que conferem resistência a antibióticos. O desenvolvimento de mamoeiros (Carica papaya L.) transgênicos tem sido baseado, até o momento, no uso de um único gene marcador, o gene npt II, que confere resistência a antibióticos como canamicina e neomicina. O presente estudo objetivou avaliar os sistemas alternativos manA/ manose e bar/ PPT como sistemas gene marcador/ agente seletivo para a variedade 'Sunrise' de mamoeiro. O desenvolvimento de embriões somáticos secundários a partir de embriões primários foi avaliado em meio de indução de embriogênese suplementado com manose e/ou sacarose. Concentrações variando entre 0,1 e 120 g/l de manose foram testadas como única fonte de carbono, ou em combinação com sacarose. O desenvolvimento de embriões somáticos secundários a partir dos primários em meio suplementado com até 120 g.L -1 de manose, como única fonte de carbono, demonstrou que este sistema não é passível de uso no desenvolvimento de mamoeiros transgênicos. Quanto ao sistema bar/ PPT, avaliou-se o desenvolvimento de embriões somáticos primários e secundários em meio suplementado com concentrações de PPT variando de zero a 150 µM. Não foi observado desenvolvimento de embriões em meio suplementado com concentração igual ou superior a 125 µM, o que sugere o uso desta concentração para a seleção de embriões transgênicos de mamoeiro.ABSTRACT -Questions relative to biosafety and public perception of genetically modified organisms have taken those involved on the development of transgenic plants to a phase out on the use of antibiotic resistance marker genes. The development of transgenic papayas (Carica papaya L.) has been based so far on the use of one only marker gene, the npt II gene, which confers resistance to antibiotics such as kanamycin and neomycin. The present study aimed to evaluate the systems manA/ mannose and bar/ PPT as alternatives marker gene/ selective agent systems to be used on the development of transgenic 'Sunrise' papayas. Therefore, the development of secondary somatic embryos from primary ones was evaluated on embryogenesis induction medium supplemented with mannose and/or sucrose. Mannose concentration ranging from 0.1 to 120 g.L -1 were tested as sole carbon source, or in conjunction with sucrose. The development of secondary somatic embryos on medium supplement with up to 120 g/l, as sole carbon source, demonstrated that this system is not applicable for the development of transgenic papayas. When evaluating the bar/ PPT system, the development of primary and secondary somatic embryos was checked for on medium supplement with zero to 150 µM of PPT. No somatic embryos developed on medium supplemented with PPT at 125 µM or more, what suggests the use of this concentration for the in vitro selection of transgenic papaya embryos.
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