Cultivation Of Transgenic Plants Research Articles

Comparison of bacterial diversity, root exudates and soil enzymatic activities in the rhizosphere of AVP1-transgenic and nontransgenic wheat (Triticum aestivum L.).

Soil microbial communities are among the most diverse communities that might be affected due to transgenic crops. Therefore, risk assessment studies on transgenes are essentially required as any adverse effects may depend not only on the specific gene and crop involved but also on soil conditions. The present study deals with the comparison of bacterial populations, root exudates and activities of soil enzymes in nontransgenic and AVP1-transgenic wheat rhizosphere, overexpressing vacuolar H + pyrophosphatase for salinity and drought stress tolerance. Amounts of organic acids and sugars produced as root exudates and activities of dehydrogenase, phosphatase and protease enzymes in soil solution showed no significant differences in AVP1-transgenic and nontransgenic wheat rhizosphere, except for urease and phenol oxidase activities. The higher copy number of nifH gene showed the abundance of nitrogen-fixing bacteria in the rhizosphere of AVP1-transgenic wheat compared with nontransgenic wheat. nifH gene sequence analysis indicated the common diazotrophic genera Azospirillum, Bradyrhizobium, Rhizobium and Pseudomonas in AVP1-transgenic and nontransgenic wheat except for Zoogloea detected only in nontransgenic wheat. Using 454-pyrosequencing of 16S rRNA gene from soil DNA, a total of 156, 282 sequences of 18 phyla were obtained, which represented bacterial (128,006), Archeal (7928) and unclassified (21,568) sequences. Proteobacteria, Crenarchaeota and Firmicutes were the most abundant phyla in the transgenic and nontransgenic wheat rhizosphere. Further comparison of different taxonomic units at the genus level showed similar distribution in transgenic and nontransgenic wheat rhizospheres. We conclude that the AVP1 gene in transgenic wheat has no apparent adverse effects on the soil environment and different bacterial communities. However, the bacterial community depends on several other factors, not only genetic composition of the host plants. The present research supports introduction and cultivation of transgenic plants in agricultural systems without any adverse effects on indigenous bacterial communities and soil ecosystems.

Evaluation of protein production in rice seedlings under dark conditions

Although plants have several advantages for foreign protein production, cultivation of transgenic plants in artificial plant growth facilities involves the use of a great amount of electricity for lightning and air conditioning, reducing cost-effectiveness. Protein production in plants grown in darkness can overcome this problem, but the amount of protein produced in the dark is unknown. In this study, the total amount of soluble protein produced in rice seedlings germinated and grown in light or darkness were examined at several time points after germination and under different temperature, nutritional, and seedling density conditions. Our results indicate that rice seedlings grown in darkness produce a comparable amount of total soluble protein to those grown in light. Furthermore, we found that the best conditions for protein production in dark-grown rice seedlings are large seeds germinated and grown for 10–12 days at 28 °C supplemented with Murashige and Skoog medium and 30 g/l sucrose in dense planting. Therefore, our results suggest that foreign proteins can be produced in rice seedlings in the dark, with a reduced electricity use and an increase in cost-effectiveness.

МОДИФИКАЦИЯ МИКРОБНОГО СООБЩЕСТВА РИЗОСФЕРЫ ТРАНСГЕННЫХ РАСТЕНИЙ ТОМАТА С ГЕНОМ СИНТЕЗА ГЛИЦИНБЕТАИНА

The change in the composition of soil microbiota as a result of the cultivation of various crops in agrocenoses is currently of great interest. The authors studied the effect of the root system of transgenic tomato plants (Solanum lycopersicum L.) grown in soil culture on the microbial community in the rhizosphere. The results showed that as a result of the cultivation of transgenic plants with the choline oxidase gene, the microbial community composition in the rhizosphere has changed significantly. A significant increase in the proportion (73%) and species diversity (Shannon index 2.25) of actinobacteria in the soil root zone of tomato transgenic codA plants as compared with control plants (10% and 0.95, respectively) has been revealed. The content of pseudomonads and micromycetes is significantly reduced (25 and 12% in transgenic plants; 70 and 81% in control plants, respectively). Thus, genetically modified plants are able to influence the microbial community structure in the rhizosphere.

Challenges and Opportunities of Genetically Modified Crops Production; Future Perspectives in Ethiopia, Review

Introduction:Genetically modified (GM) crop species were proven to be a solution for the increasing food consumption in many countries. The cultivation of transgenic plants is increasing from time to time. In 2017 alone, 27 different genetically modified (GM) crop species were produced in 40 countries.Explanation:Biotechnology is revolutionizing science, promising to solve hunger, malnutrition and production demands of industrial raw materials from plants. However, there are biosafety concerns that GM crops may have unintended and hazardous impacts on living organisms well-being and environment both on target and non-target organisms. To tackle such potential problems many countries are implementing international as well as national biosafety regulations. America, Brazil, Belgium, China and India are among the top GM crop users in the world, whereas Egypt, Sudan, South Africa and Burkina Faso are leading GM crop producers in Africa. Ethiopia has also developed its own policy and biosafety regulations for biotechnology products.Conclusion:The Ethiopian government has given due attention to GM crops as a tool for the transformation of agricultural productivity and quality. Before a couple of years, Bt cotton (cotton containing toxic protein fromBacillus thuringiensis) has been introduced to Ethiopia and is expected to bring fundamental change in the production of fibers for the textile industries and also will have crucial consequence to the forthcoming use of the modern biotechnological Science in the country. The introduction of Bt cotton is a typical example worth mentioning here which shows a relative flexibility of the current Ethiopian biosafety regulation. This paper reviews the possible challenges and opportunities of using GM crops in Ethiopia.

The Romanian experience and perspective on the commercial cultivation of genetically modified crops in Europe.

Romania was the third country in Europe and the tenth in the world, to commercially adopt genetically modified crops in 1999, only 3years after they were first marketed globally. Half a million hectares of transgenic herbicide resistant soybean and insect resistant maize were grown in Romania during an uninterrupted 17-year period. After several years of continued declining area, the commercial cultivation of transgenic plants recently ended. The commercial cultivation of transgenic crops in Romania remains legally and technically possible, according to the EU and national regulations. However, the declining area cultivated with these crops in Romania seems to be the result of farmers' conscious decision, while waiting for more profitable genetically modified crops to become available that better fit their needs. This expectation would be a logical result of the EU GMO opt-out Directive 2015/412 and the advent of the new plant breeding techniques. The GMO opt-out mechanism is still expected to unblock the EU authorization process after the large majority of the EU member states have already prohibited the cultivation of genetically modified organisms in their territory. As the new plant breeding techniques offer significant technical and economic advantages, they could be rapidly adopted by commercial breeders and farmers outside Europe. The Court of Justice of the European Union ruled that plants obtained with the new gene editing techniques must go through the same authorization procedure as transgenic plants. This decision is expected to delay the approval and availability of these new plant varieties on the EU market and their commercial cultivation.

Single-tube hydroponics as a novel idea for small-scale production of crop seed in a plant incubator.

We present a novel protocol for small-scale production of crop seed in a plant incubator termed "Single-tube hydroponics." Our protocol minimizes the materials and methods for cultivation whereby a large number of independent plants can be cultured in a limited space. This study may aid in the improvement of crop seed components, especially in the cultivation of transgenic plants.

Transgenic tobacco revealing altered bacterial diversity in the rhizosphere during early plant development

The rhizosphere constitutes a complex niche that may be exploited by a wide variety of bacteria. Bacterium-plant interactions in this niche can be influenced by factors such as the expression of heterologous genes in the plant. The objective of this work was to describe the bacterial communities associated with the rhizosphere and rhizoplane regions of tobacco plants, and to compare communities from transgenic tobacco lines (CAB1, CAB2 and TRP) with those found in wild-type (WT) plants. Samples were collected at two stages of plant development, the vegetative and flowering stages (1 and 3 months after germination). The diversity of the culturable microbial community was assessed by isolation and further characterization of isolates by amplified ribosomal RNA gene restriction analysis (ARDRA) and 16S rRNA sequencing. These analyses revealed the presence of fairly common rhizosphere organisms with the main groups Alphaproteobacteria, Betaproteobacteria, Actinobacteria and Bacilli. Analysis of the total bacterial communities using PCR-DGGE (denaturing gradient gel electrophoresis) revealed that shifts in bacterial communities occurred during early plant development, but the reestablishment of original community structure was observed over time. The effects were smaller in rhizosphere than in rhizoplane samples, where selection of specific bacterial groups by the different plant lines was demonstrated. Clustering patterns and principal components analysis (PCA) were used to distinguish the plant lines according to the fingerprint of their associated bacterial communities. Bands differentially detected in plant lines were found to be affiliated with the genera Pantoea, Bacillus and Burkholderia in WT, CAB and TRP plants, respectively. The data revealed that, although rhizosphere/rhizoplane microbial communities can be affected by the cultivation of transgenic plants, soil resilience may be able to restore the original bacterial diversity after one cycle of plant cultivation.

Transgenic cotton could safely be grown since CpTI toxin rapidly degrades in the rhizosphere soil

Cultivation of transgenic plants is debated worldwide. Potential environmental risks have to be considered, before acceptance of expanding cultivation, despite the advantages of the use of fewer pesticides. Here, the potential effects on soil ecosystems of transgenic plants have been studied. As a model, genetically engineered cotton producing cowpea trypsin inhibitor (CpTI) has been used. The degradation of CpTI in the rhizosphere of the transgenic CpTI+Bt (Bacillus thuringiensis) cotton cultivar SGK321 was assessed. During plant development, concentrations of CpTI toxin in the rhizosphere were measured using an enzyme-linked immunosorbent assay (ELISA). As the plants developed, the residue of CpTI in the rhizosphere increased, and reached a peak at topping stage (100 days after planting). After this stage, the residue began to decrease, and was nil the following year (258 days after planting). The conclusion is that genetically engineered cotton can safely be cultivated since no accumulation of substances released from the transgenic plants was persistent in the soil.

Effect of crop rotation and soil cover on alteration of the soil microflora generated by the culture of transgenic plants producing opines.

The culture of transgenic Lotus corniculatus plants producing opines, which are bacterial growth substrates, leads to the selection of rhizospheric bacteria able to utilize these substrates. We have investigated the fate of the opine-utilizing community over time under different experimental conditions following elimination of selective pressure exerted by the transgenic plants. These plants were removed from the soil, which was either left unplanted or replanted with wild-type L. corniculatus or wheat plants. The density of opine-utilizing bacteria in the fallow soils remained essentially unchanged throughout the experiment, regardless of the soil of origin (soil planted with wild-type or transgenic plants). When wild-type Lotus plants were used to replace their transgenic counterparts, only the bacterial populations able to utilize the opines were affected. Long-term changes affecting the opine-utilizing bacterial community on Lotus roots was dependent upon the opine studied. The concentration of nopaline utilizers decreased, upon replacement of the transgenic plants, to a level similar to that of normal plants, while the concentration of mannopine utilizers decreased to levels intermediate between transgenic and normal plants. These data indicate that: (i) the opine-utilizing bacterial populations can be controlled in the rhizosphere via plant-exudate engineering; (ii) the interaction between the engineered plants and their root-associated micro-organisms is transgene specific; and (iii) alterations induced by the cultivation of transgenic plants may sometimes be persistent. Furthermore, opine-utilizing bacterial populations can be controlled by crop rotation. Therefore, favouring the growth of a rhizobacterium of agronomic interest via an opine-based strategy appears feasible.

Influence of the bioherbicide phosphinothricin on interactions between phytopathogens and their antagonists

Phosphinothricin is a microbial toxin currently under development as a selective weed killer in the cultivation of transgenic plants engineered to resist its presence. Here it is shown that phosphinothricin is inhibitory to antagonistic soil microorganisms including Bacillus subtilis, Pseudomonas flourescens, and many species of Trichoderma. Phosphinothricin was also inhibitory to the phytopathogenic fungi Rhizoctonia solani and Sclerotinia sclerotiorum. In contrast, phytopathogens Fusarium oxysporum and Pythium aphanidermatum were highly resistant to phosphinothricin. In pathogen–antagonist challenges, species of Trichoderma that parasitize F. oxysporum and P. aphanidermatum were eliminated when phosphinothricin was added to the growth media. Similarly, the ability of Pseudomonas fluorescens to exclude Pythium aphanidermatum was markedly affected by the presence of phosphinothricin in the media. The dominance equilibrium between Trichoderma species and the bacterium Bacillus subtilis was influenced in favor of the former at 0 and 5 mM concentrations of the herbicide and in favor of the latter at 1 mM concentrations. Pseudomonas fluorescens was unable to exclude Trichoderma species regardless of the phosphinothricin concentration in the media. Key words: phosphinothricin, pathogens, fungi, bacteria, antagonists, biocontrol.