Introduction of a synthetic Thermococcus-derived α-amlyase gene into barley genome for increased enzyme thermostability in grains

Background: The enzymes utilized in the process of beer production are generally sensitive to higher temperatures. About 60% of them are deactivated in drying the malt that limits the utilization of starting material in the fermentation process. Gene transfer from thermophilic bacteria is a promising tool for producing barley grains harboring thermotolerant enzymes. Results: Gene for α-amylase from hydrothermal Thermococcus, optimally active at 75­85°C and pH between 5.0 and 5.5, was adapted in silico to barley codon usage. The corresponding sequence was put under control of the endosperm-specific promoter 1Dx5 and after synthesis and cloning transferred into barley by biolistics. In addition to model cultivar Golden Promise we transformed three Slovak barley cultivars Pribina, Levan and Nitran, and transgenic plants were obtained. Expression of the ~50 kDa active recombinant enzyme in grains of cvs. Pribina and Nitran resulted in retaining up to 9.39% of enzyme activity upon heating to 75°C, which is more than 4 times higher compared to non-transgenic controls. In the model cv. Golden Promise the grain α-amylase activity upon heating was above 9% either, however, the effects of the introduced enzyme were less pronounced (only 1.22 fold difference compared with non-transgenic barley). Conclusions: Expression of the synthetic gene in barley enhanced the residual α-amylase activity in grains at high temperatures.

Over-expression of dehydroascorbate reductase enhances oxidative stress tolerance in tobacco

Background: Ascorbic acid (Asc) is one of the most abundant antioxidants and it serves as a major contributor to protect plants against oxidative damage. Plants use two enzymes that participate in the metabolic recycling of Asc. One of these two enzymes is dehydroascorbate reductase (DHAR). It directly regenerates Asc from its oxidized state and thus prevents Asc from being irreversibly hydrolyzed to 2, 3-diketogulonic acid. This study aimed to examine whether over-expression of DHAR leads to an enhanced oxidative stress tolerance in tobacco plants. Results: In this study, we functionally characterized a novel JcDHAR gene from Jatropha curcas and found via quantitative RT-PCR analysis that JcDHAR can be induced with H2O2, salt and PEG stresses. The DHAR activities of transgenic tobacco plants increased from 2.0 to 5.3 fold compared to wild-type plants. As a result, the transgenic plants displayed enhanced tolerance to oxidative stress. Conclusions: Our results indicate that JcDHAR expression can effectively enhance the tolerance to oxidative stress in plants.

A choline monooxygenase gene promoter from Salicornia europaea increases expression of the -glucuronidase gene under abiotic stresses in tobacco (Nicotiana tabacum L.).

A 1312 bp 5' flanking region of Salicornia europaea choline monooxygenase (SeCMO) gene was isolated using the anchored PCR. To investigate the mechanism of regulation for this stress-induced gene, the SeCMO promoter--glucuronidase (GUS) chimeric gene constructs containing five deletions F1, F2, F3, F4 and F5 were introduced into tobacco (Nicotiana tabacum L.) by Agrobacterium-mediated transformation. The functional properties of each promoter fragment were examined by assaying GUS activity in the leaves of transgenic tobacco treated with abiotic stresses (NaCl, PEG6000 and low temperature). The GUS activity in transgenic tobacco with F2 (-1056 to +8) construct showed highest increase under all the three abiotic stresses. Thus, the study provided a potential promoter induced by the salt, dehydration and cold for the plant genetic manipulation.

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.

GMOs: building the future on the basis of past experience

Biosafety of genetically modified organisms (GMOs) and their derivatives is still a major topic in the agenda of government and societies worldwide. The aim of this review is to bring into light that data that supported the decision taken back in 1998 as an exercise to stimulate criticism from the scientific community for upcoming discussions and to avoid emotional and senseless arguments that could jeopardize future development in the field. It must be emphasized that Roundup Ready® soybean is just one example of how biotechnology can bring in significant advances for society, not only through increased productivity, but also with beneficial environmental impact, thereby allowing more rational use of agricultural pesticides for improvement of the soil conditions. The adoption of agricultural practices with higher yield will also allow better distribution of income among small farmers. New species of genetically modified plants will soon be available and society should be capable of making decisions in an objective and well-informed manner, through collegiate bodies that are qualified in all aspects of biosafety and environmental impact.

A biosegurança dos organismos geneticamente modificados e seus derivados é um dos principais tópicos na agenda de discussões de governos e sociedades. O objetivo desta revisão é reviver os dados científicos que fundamentaram a decisão de liberação comercial da soja transgênica resistente ao Glifosate com o intuito de estimular uma posição crítica da comunidade científica para as próximas discussões no tema. A soja em questão é apenas um exemplo de como a biotecnologia pode contribuir para avanços na produtividade e na preservação do meio ambiente, com ganho de produtividade e lucratividade para agricultores em todas as escalas. Novas variedades trangênicas estarão na pauta de discussões que deverão estar fundamentadas em dados científicos objetivos, evitando argumentos emocionais que poderão, assim como no passado recente, prejudicar o desenvolvimento científico e tecnológico da agricultura.