Characterization of AhLea-3 and its enhancement of salt tolerance in transgenic peanut plants

BACKGROUND: Late embryogenesis abundant (LEA) proteins were reported to be related to adversity stress and drought tolerance. Lea-3 from Arachis hypogaea L. (AhLea-3) was previously found to be related to salt tolerance according to the result of transcriptome profiling and digital gene expression analysis. So, AhLea-3 was cloned and the salt tolerance was validated by transgenic peanut plants. RESULTS: AhLea-3 was isolated from M34, a salt-resistant mutant of peanut, with its cDNA as the template. AhLea-3 contains one intron and two extrons, and the full-length cDNA sequence contains 303 bp. AhLea3 was ligated to pCAMBIA1301 to obtain the overexpression vector pCAMBIA1301-AhLea-3, which was then transferred into peanut variety Huayu23. The expression level of AhLea-3, as determined by qRTPCR analysis, was >10 times higher in transgenic than in non-transgenic plants. Five days after they were irrigated with 250 mM NaCl, the transgenic plants showed less severe leaf wilting, higher activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase), and lower malonic dialdehyde content than non-transgenic plants. Relative to non-transgenic plants, the transgenic plants had a higher photosynthetic net rate, stomatal conductance, and transpiration rate, and a lower intercellular CO2 concentration after salt stress treatment (250 mM NaCl). CONCLUSIONS: These results indicate that overexpression of AhLea-3 increased the salt tolerance of transgenic peanut plants. AhLea-3 might become a useful gene resource for the variety breeding of salinity tolerance in peanut.

Overexpression of NtAGPase small subunit gene increases leaf starch content and tobacco biomass / 生物工程学报

Production of biofuels such as ethanol from non-grain crops may contribute to alleviating the global energy crisis and reducing the potential threat to food security. Tobacco (Nicotiana tabacum) is a commercial crop with high biomass yield. Breeding of starch-rich tobacco plants may provide alternative raw materials for the production of fuel ethanol. We cloned the small subunit gene NtSSU of ADP-glucose pyrophosphorylase (NtAGPase), which controls starch biosynthesis in tobacco, and constructed a plant expression vector pCAMBIA1303-NtSSU. The NtSSU gene was overexpressed in tobacco upon Agrobacterium-mediated leaf disc transformation. Phenotypic analysis showed that overexpression of NtSSU gene promoted the accumulation of starch in tobacco leaves, and the content of starch in tobacco leaves increased from 17.5% to 41.7%. The growth rate and biomass yield of the transgenic tobacco with NtSSU gene were also significantly increased. The results revealed that overexpression of NtSSU gene could effectively redirect more photosynthesis carbon flux into starch biosynthesis pathway, which led to an increased biomass yield but did not generate negative effects on other agronomic traits. Therefore, NtSSU gene can be used as an excellent target gene in plant breeding to enrich starch accumulation in vegetative organs to develop new germplasm dedicated to fuel ethanol production.

Composição nutricional de milho Bt ensilado com inoculante enzimobacteriano e avaliado em ovinos / Nutritional composition of GMO corn ensiled with bacterial inoculants and sheep digestibility

O objetivo foi avaliar as características agronômicas e químico-bromatológicas de dois híbridos de milho Bt (30F35H e CD397YH) ensilados com inoculante enzimobacteriano. Os teores de FDN foram semelhantes para todas as frações de planta, já o teor de FDA diferiu quanto à planta inteira e colmo, enquanto a lignina diferiu em relação à planta inteira, colmo e sabugo. A DIVMS não apresentou diferença entre os híbridos em nenhuma das frações. As silagens foram produzidas em silos experimentais (aproximadamente 200kg). As concentrações de MS, EE, FDN, NDT e DIVMS não mostraram diferença entre as silagens dos híbridos avaliados. Já os teores de MM, PB, FDA e lignina diferiram. Não houve diferença entre as silagens dos híbridos para os valores de NDT estimado e para a DIVMS. Também não foi observado efeito do inoculante sobre os valores de CHT, CNF, FDN e DIVMS. Conclui-se que o híbrido Pioneer foi superior ao Coodetec em produtividade de MV ha-1, porém a composição nutricional das silagens não diferiu na concentração de NDT e digestibilidade avaliadas em ovinos. Não houve efeito do uso de inoculante na digestibilidade da matéria seca e da fração fibra em detergente neutro das silagens.

The aim was to evaluate the agronomic characteristics and chemical composition of the two corn hybrids (30F35H and CD397YH) ensiled with enzymatic bacterial inoculants. NDF were similar for all plant fractions, since the ADF content differed as to the whole plant and stem, lignin differed in relation to the whole plant, stem and cob. IVDMD did not differ among treatments in any of the fractions. The silages were produced in experimental silos (approximately 200kg). The concentrations of MS, EE, NDF, IVDMD and TDN showed no difference between the silages of hybrids. Since the levels of MM, CP, ADF and lignin differed; there was no difference between hybrids for silage TDN and IVDMD. There was also no effect of the use of inoculants on the values of CHT, NFC, NDF and IVDMD. It is concluded that Pioneer was superior to Coodetec productivity of MV-1 ha. The nutritional composition of silages did not differ in the concentration of TDN and digestibility in sheep assessed. There was no effect of using inoculants on the digestibility of dry matter and neutral detergent fiber content of the silage.

The lld mutation in Pisum sativum used as a genetic tool to discern the plant leaflet/leaf developmental process.

Leaves of P. sativum the double mutant genotype tendril-less (tl) leaflet-development (lld), due to the action of lld mutation, produce many leaflets that are aborted at different stages of development. Morphological, vein pattern and histological observations showed that aborted leaflets became cup/bell/trumpet (cup) shaped because of segmental differentiation in the leaflet primordium. Cup’s inside lamina surface was adaxial and outer surfaces of cup and its stem were abaxial. The lld cups were phenotypically homologous to aborted leaves described in Arabidopsis thaliana mutants, angustifolia and those which underexpressed the HD-ZIP III proteins. Leaflet primordium was found to grow and establish three dimensional polarities apex-downwards. Primordium produced lateral outgrowth on one side of midvein. Differentiation, in the outgrowth, of secondary veins, whose xylem tissues faced each other, established the adaxial-abaxial polarity. Lateral outgrowth then developed a cavity which got bounded by future adaxial epidermis. Further growth, veinlet formation, differentiation of palisade parenchyma and spongy parenchyma followed. Opening of lateral outgrowth at its outer midline produced a flat leaflet with lateral lamina spans. The structural and functional correspondence between leaflet and simple leaves suggested commonality between leaf and leaflet development mechanisms. A molecular model for the lld led leaflet abortion was also provided.

Transgênicos - Plantas Produtoras de Fármacos (PPF) / Trangenics - Plant-Based Drugs (PBD)

Plant-Based Drugs - PBD - represent the 4th generation of genetically-modified plants and in this case the technology is used to develop and produce pharmaceuticals vaccines and/or products from transgenic seeds. This technology, like all scientific innovations, has inherent risks. However, the current knowledge available about the use of this technology means that no firm conclusions can be drawn about the nature of the risks involved, as well as their significance and the likelihood of causing serious damage or not. Risk analysis should be the starting premise prior to any implementation of techno-scientific innovations. The parameters must be evaluated and precautions taken and research must be conducted in a detailed and broad-ranging manner with respect to the potential risks of any innovation. This article analyzed the applicability of this new technology, as well as risk management and containment in order to guarantee safe use, handling and consumption by human beings.

As Plantas Produtoras de Fármacos (PPF) representam a 4ª onda de vegetais geneticamente modificados. Neste caso, com a tecnologia sendo empregada para desenvolver e produzir vacinas e/ou produtos farmacêuticos, a partir de plantas transgênicas. Esta tecnologia, como todas as inovações científicas, vem acompanhada de riscos. Porém, o conhecimento atual disponível sobre seu uso não permite ainda conclusões definitivas sobre o caráter dos riscos, sua significância e sua probabilidade de causar, ou não, sérios danos. A análise de risco deve servir de base para a implementação de inovações tecnocientíficas. Os parâmetros devem ser avaliados, precauções especiais devem ser tomadas, a pesquisa deve ser conduzida de forma detalhada e também precisa ter amplo alcance quanto aos riscos potenciais por ser uma inovação. O presente artigo revisou a aplicabilidade desta nova tecnologia com relação ao gerenciamento do risco e a uma contenção que vise a segurança de uso, a manipulação e o comércio para os seres humanos.

Expression of SOD transgene in pepper confer stress tolerance and improve shoot regeneration / Expresión del transgén SOD en el pimiento que confiere tolerancia al estrés y mejora la regeneración de brotes

The objective of this work was to study the stress tolerance and regeneration capability of transgenic pepper plants carrying a sod gene, encoding a tomato chloroplast-localized Cu/Zn SOD protein. The expression of the sod gene was confirmed by enzymatic staining following polyacrylamide gel electrophoresis (PAGE), revealing a ‘novel’ band, which could represent a heterodimeric enzyme. Transgenic T1 and T2 progeny plants were exposed to different oxidative stresses including Methyl viologen (MV) and drought and found to have an increased resistance to oxidative damage. Furthermore, the SOD carrying transgenic pepper plants showed increased levels of regeneration efficiency compared to the wild type pepper plants. Pepper is a recalcitrant species in terms of its in vitro regeneration ability but it could be extremely useful for the development of pharmaceuticals. This approach enables the extent use of pepper for genetic transformation and the production of high valuable products in plants particularly the large fruit varieties.

Phytoremediation of toxic metals from soil and waste water.

Phytoremediation is an emerging technology, which uses plants and their associated rhizospheric microorganisms to remove pollutants from contaminated sites. This plant based technology has gained acceptance in the past ten years as a cheap, efficient and environment friendly technology especially for removing toxic metals. Plant based technologies for metal decontamination are extraction, volatilization, stabilization and rhizofiltration. Various soil and plant factors such as soil's physical and chemical properties, plant and microbial exudates, metal bioavailability plant's ability to uptake, accumulate, translocate, sequester and detoxify metal amounts for phytoremediation efficiency. Use of transgenics to enhance phytoremediation potential seems promising. Despite several advantages, phytoremediation has not yet become a commercially available technology Progress in the field is hindered by lack of understanding of complex interactions in the rhizosphere and plant based mechanisms which allow metal translocation and accumulation in plants. The review concludes with suggestions for future phytoremediation research.

Are high-lysine cereal crops still a challenge?

The essential amino acids lysine and threonine are synthesized in higher plants via a pathway starting with aspartate that also leads to the formation of methionine and isoleucine. Lysine is one of most limiting amino acids in plants consumed by humans and livestock. Recent genetic, molecular, and biochemical evidence suggests that lysine synthesis and catabolism are regulated by complex mechanisms. Early kinetic studies utilizing mutants and transgenic plants that over-accumulate lysine have indicated that the major step for the regulation of lysine biosynthesis is at the enzyme dihydrodipicolinate synthase. Despite this tight regulation, recent strong evidence indicates that lysine catabolism is also subject to control, particularly in cereal seeds. The challenge of producing crops with a high-lysine concentration in the seeds appeared to be in sight a few years ago. However, apart from the quality protein maize lines currently commercially available, the release of high-lysine crops has not yet occurred. We are left with the question, is the production of high-lysine crops still a challenge?.