Bt Lines Research Articles

Introduction of Bacillus thuringiensis (Bt) gene does not reduce potassium use efficiency of Bt transgenic cotton (Gossypium hirsutum L.)

BackgroundPotassium (K) deficiency has become a common field production problem following the widespread adoption of Bacillus thuringiensis (Bt) transgenic cotton (Gossypium hirsutum L.) worldwide. The purpose of this study was to clarify whether the introduction of Bt gene directly reduces the K-use efficiency of cotton to induce K deficiency.ResultsThe cotton variety, Jihe 321 (wild type, WT) and its two Bt (Cry1Ac)-transgenic overexpression lines (OE-29317, OE-29312) were studied in field with low soil-test K+ (47.8 mg·kg−1). In the field with low soil-test K+, only OE-29317 had less biomass and K+ accumulation than the WT at some growth stages. Both Bt lines produced similar or even greater seed cotton yield than WT in the field. When the Bt gene (~ 70%) in OE-29317 and OE-29312 plants was silenced by virus-induced gene silencing (VIGS), the VIGS-Bt plants did not produce more biomass than VIGS-green fluorescent protein (control) plants.ConclusionsThe introduction of Bt gene did not necessarily hinder the K use efficiency of the cotton lines under this study.

No Adverse Effects of Stacked Bacillus thuringiensis Maize on the Midge Chironomus riparius

Material from genetically engineered maize producing insecticidal Cry proteins from Bacillus thuringiensis (Bt) may enter aquatic ecosystems and expose nontarget organisms. We investigated the effects on life table parameters of the midge Chironomus riparius (Diptera: Chironomidae) of SmartStax maize leaves, which contain six different Cry proteins targeting Lepidoptera and Coleoptera pests, in two plant backgrounds. For midge development and emergence, 95% confidence intervals for the means of six conventional maize lines (Rheintaler, Tasty Sweet, ES‐Eurojet, Planoxx, EXP 258, and EXP 262), were used to capture the natural range of variation. For reproduction, lowest and highest means were used. The natural range of variation allows one to judge whether observed effects between Bt maize and the closest non‐Bt comparator are likely to be of biological relevance. No adverse effects on C. riparius were observed with any Bt maize line compared with the respective non‐Bt counterpart. Development time was shorter when females were fed Bt maize than when they were fed non‐Bt maize, but this effect was not considered adverse. Development time, emergence ratio, sex ratio, and larvae/egg rope measured for Bt maize were within the natural range of variation. Fecundity for the Bt lines was equal to or higher than that for the conventional lines. Future risk assessment studies may consider plant background effects and the natural range of variation to judge the relevance of observed differences between particular genetically engineered and non‐genetically engineered plants. Environ Toxicol Chem 2022;41:1078–1088. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Genetic diversity analysis in Bt introgressed and non-Bt lines of upland cotton (Gossypium hirsutum L.)

Diversity analysis of Bt lines, a prerequisite to heterosis breeding, are rarely published. Diversity analysis of 140 cotton genotypes comprising of BGI, BGII and Non-Bt lines resulted in the grouping of genotypes into 20 clusters among which five had multiple genotypes and 15 others were solitary. Specific clustering of genotypes of BGI and BGII was not observed which got distributed across the clusters. The maximum and minimum inter-cluster distances were observed between two solitary clusters XVI and XVIII (159.8) as well as clusters VII and XI (6.4), respectively, reflecting diverse and close relationship among the Bt genotypes of those clusters. Two pairs of isogenic lines were located in the same clusters as they shared the same genetic background. The genetic background played important role in the diversity rather than the Bt status of genotype. Also, the maximum genetic diversity (64%) was arising from traits which were not related to Bt genes such as plant height, boll weight, and ginning out-turn when compared to the characters related to Bt gnes such as seed cotton yield and boll number (33%). In general, for seed cotton yield, BGI outperformed BGII lines. The study helped in developing high yielding hybrids through diverse parental line selections. Key words: Bt cotton, Genetic diversity, Introgression, D2 analysis

Differential impact of Bt-transgenic rice plantings on bacterial community in three niches over consecutive years

Transgenic-Bacillus thuringiensis (Bt) crops express insecticidal proteins, which can accumulate in plants and soil where they may influence microbial populations. The impact of Bt crops on bacterial communities has only been assessed under short-term, and results have been contradictory. Here, we analyzed the bacterial communities in three niches, rhizosphere soil (RS), root endosphere (RE) and leaf endosphere (LE), of three Bt rice and their non-Bt parental lines for three consecutive years by high-throughput sequencing. In principal coordinate analysis (PCoA) and PERMANOVA (Adonis) analysis, operational taxonomic units (OTUs) were clustered primarily by niche type and differed significantly in the RE and LE but not in the RS between each of three Bt lines compared with the non-Bt rice line, and not in each respective niche among the three Bt rice lines. The bacterial communities in the RS of different rice lines over the 3 years were clustered mainly by year rather than by lines. The differential bacterial taxa among the lines did not overlap between years, presumably because Cry proteins are rapidly degraded in the soil. A network analysis of RS bacterial communities showed that the network complexity and density for the three Bt rice lines did not decrease compared with those for the non-Bt line. In conclusion, our results demonstrated that bacterial communities differed significantly in RE and LE between Bt and non-Bt rice lines, but the differences were mild and transient, and had no adverse impact on RS over the 3 years. This study provides favorable evidence in support of the commercialization of Bt rice.

Evaluation of pollen viability, seed viability and vigor of two Bt rice lines Y7 and P8 carrying cry1B::cry1Aa fusion genes

Pollen viability, seed viability and seed vigor of two BT lines Y7 and P8 expressing Cry1B-Cry1Aa fusion proteins were assessed to determine if these two lines equivalence to its wild type rice cv Rojolele. Pollen viability was estimated using in vitro pollen germination methods. Pollen were collected at 0, 1, and 2h after shedding. Both seed viability and vigor were observed using rolled paper test methods at incubation temperature of 30, 33, 37, and 42 °C. The results showed that there was no significant difference between pollen viability of BT lines and Rojolele wild type. The highest pollen viability was obtained when the pollen grown shortly after anthesis (0h). Seed viability and vigor were significantly affected by the incubation temperature. The highest seed viability and vigor were obtained at incubation temperature of 33 °C. Both seed viability and vigor were decreased significantly when the seeds grown at higher temperature (37 °C). However, seed viability and vigor of BT lines were not significantly difference from its wild type, except for the fresh weight parameters. Thus, based on these observations, BT lines were agronomically equivalence to wild type rice cv Rojolele. This data is important for the environmental risk assessment.

Cotton Fleahopper1 Biology and Ecology Relevant to Development of Insect Resistance Management Strategies

Since the success of the U.S. Boll Weevil Eradication Program and widespread adoption of genetically modified crops, the cotton fleahopper, Pseudatomoscelis seriatus (Reuter), has reemerged as a significant cotton pest. Current management strategies for the pest are based primarily on foliar applications of insecticides. A line of cotton that produces modified Bt Cry51Aa2 protein was developed for Lygus spp., but the protein has also shown activity against the cotton fleahopper. Consequently, before this new Bt line can be released commercially, refuge requirements and other Insect Resistance Management (IRM) strategies mandated by the Environmental Protection Agency need to be established to prevent or delay development of resistance by cotton fleahopper to the new toxin. In response, we provide and discuss relevant information on the biology and ecology of the cotton fleahopper, including life history, host preference, dispersal, and population genetic structure, that may be useful for developing IRM strategies for the pest.

Transgenic cowpea plants expressing Bacillus thuringiensis Cry2Aa insecticidal protein imparts resistance to Maruca vitrata legume pod borer.

Fertile independent transgenic cowpea lines expressing the BtCry2Aa toxin with increased resistance to the most devastating lepidopteran insect pest, Maruca pod borer has been developed for the first time. Cowpea is a staple legume important for food and nutritional security in sub-Saharan Africa and Asia, where its production is limited by the key pest, legume pod borer (Maruca vitrata). Cowpea varieties resistant to M. vitrata are not known, hence, development of Maruca pod borer resistance cowpea through genetic engineering is a promising approach to improve its production. In the present study, transgenic cowpea plants expressing Bacillus thuringiensis Cry2Aa insecticidal protein were developed for the first time using Agrobacterium tumefaciens-mediated transformation of cotyledonary explants. T0 plants recovered from Agrobacterium cocultured explants on medium containing 120 mgl-1 of kanamycin were identified on the basis of the presence of transgenes by PCR, their integration into genome by Southern hybridization and expression of their transcripts by semi quantitative PCR (sqRT-PCR) and quantitative Real-time-PCR (qRT-PCR) and protein by Western blot analysis. The transformation efficiency obtained was 3.47% with 11 independent T0 transgenic lines. The bioefficacy of Cry2Aa protein expressed in randomly selected four T0 plant's leaves and pods was evaluated by feeding Maruca pod borer demonstrated a significant lower damage and a high level of Maruca mortality (more than 90%) for all these Bt lines. The inheritance of transgenes from T0 to T1 progeny plants was demonstrated by PCR analysis. The transgenic plants generated in this study can be used in cowpea breeding program for durable and sustainable legume pod borer resistance.

Synthesis of Novel Chitosan-Grafted-Derivatives Nano Cationic Polymers as Antitumor Agents

Chitosan obtained from isolated chitin of shrimp shells by a modified chemical method with a high degree of deacetylation to improve its solubility. This was undergoing a graft copolymerization process to prepare acetyl chitosan (NACS), acetyl chitosan grafted polylactide (NACS-g-PLA), chitosan grafted polylactide (CS-PLA), and polylactide chitosan grafted poly(ethylene glycol) (CS- PLA-g-PEG) nanoparticles. They characterized by FT-IR and 1HNMR. Chitosan and its derivative nanoparticles morphology examined using SEM and average nanoparticle size counted by ImageJ program. After treatment with chitosan derivative nanoparticles (1 mg/mL) at various time intervals (24, 48 and 72 hour) for three different models of human breast cancer cell lines which are BT, MCF-7 and SKBR3 cell lines, the cell proliferation, cell viability percentage, and genotoxicity as a DNA fragmentation index (%DFI) were analysed by MTT assay, and flow cytometry techniques. The results displayed that CSNPs and its derivatives NACS-g-PLA, CS-g-PLA NPs, and CS- PLA-g-PEG, have strong antitumor activities by inducing in vitro treated BT, MCF-7, and SKBR3 cell lines as a highly significant effect, (p < 0.001) on cell proliferation growth as observed with untreated control cells in a different pattern. Furthermore, it can be said since genotoxicity results that prepared polymers NPs were considered as slight /or no effect on the nucleic material of the BT cell lines, as demonstrated as %DFI in compare with positive and negative control samples.

Deletion of the thymidine kinase gene attenuates Caprine alphaherpesvirus 1 in goats

Caprine alphaherpesvirus 1 (CpHV-1) is a pathogen associated with systemic infection and respiratory disease in kids and subclinical infection or reproductive failure and abortions in adult goats. The enzyme thymidine kinase (TK) is an important viral product involved in nucleotide synthesis. This property makes the tk gene a common target for herpesvirus attenuation. Here we deleted the tk gene of a CpHV-1 isolate and characterized the recombinant CpHV-1ΔTKin vitro and in vivo. In vitro characterization revealed that the recombinant CpHV-1ΔTK replicated to similar titers and produced plaques of similar size to the parental CpHV-1 strain in BT and CRIB cell lines. Upon intranasal inoculation of young goats, the parental virus replicated more efficiently and for a longer period than the recombinant virus. In addition, infection with the parental virus resulted in mild systemic and respiratory signs whereas the kids inoculated with the recombinant CpHV-1ΔTK virus remained healthy. Goats inoculated with the parental virus also developed higher neutralizing antibody titers when compared to CpHV-1ΔTK inoculated animals. Dexamethasone (Dx) administration on days 35–39 post-inoculation did not result in virus shedding in nasal secretions, indicating lack of reactivation from latency. However, viral DNA was detected in the trigeminal ganglia of animals euthanized at 14 days post-Dx, indicating that both viruses successfully established latent infection. Our results show that the recombinant CpHV-1ΔTK presents an attenuated phenotype when compared to the parental virus, and hence may represent a promising vaccine candidate to prevent CpHV-1 disease in goats.

Inheritance of Transgenes in Transgenic Bt Lines Resistance to Helicoverpa armigera in Upland Cotton.

Six transgenic Bt cotton cultivars (lines) including GKsu12, GK19, MR1, GK5, 109B, and SGK1 are highly resistant to bollworm from the seedling to boll-setting stages in bioassays with detached cotton leaves, though there are differences in resistant level and Bt toxin content in these transgenic cottons. Genetics analysis reveals that the resistance to Helicoverpa armigera in these six transgenic Bt cotton cultivars (lines) are controlled by one pair of dominant genes. Allelic tests further demonstrate some populations are in Mendel segregation for two nonallelic genes, i.e., the inserted Bt gene in GKsu12 is nonallelic to that of SGK1, GK5, 109B, and GK19, and Bt genes in GK19 and SGK1 are likely inserted in the same or in close proximity (genetically closely linked), while some F2 produce abnormal segregation patterns, with a segregation of resistance to Helicoverpa armigera which vary between 15:1 and 3:1, though their Bt segregation fit into 15:1 by PCR analysis, suggesting Bt gene silence in these populations. Two genes silence may occur in these populations due to the homologous sequence by crossing since the silenced individuals accounted for 1/16 of the F2 populations for allelic test. To those silenced populations, one of their parents all showed high resistance to bollworm.

Bt eggplant (Solanum melongena L.) in Bangladesh: Fruit production and control of eggplant fruit and shoot borer (Leucinodes orbonalis Guenee), effects on non-target arthropods and economic returns.

Eggplant or brinjal (Solanum melongena) is a popular vegetable grown throughout Asia where it is attacked by brinjal fruit and shoot borer (BFSB) (Leucinodes orbonalis). Yield losses in Bangladesh have been reported up to 86% and farmers rely primarily on frequent insecticide applications to reduce injury. Bangladesh has developed and released four brinjal varieties producing Cry1Ac (Bt brinjal) and is the first country to do so. We report on the first replicated field trials comparing four Bt brinjal varieties to their non-Bt isolines, with and without standard insecticide spray regimes. Results of the two-year study (2016–17) indicated Bt varieties had increased fruit production and minimal BFSB fruit infestation compared with their respective non-Bt isolines. Fruit infestation for Bt varieties varied from 0–2.27% in 2016, 0% in 2017, and was not significantly affected by the spray regime in either year. In contrast, fruit infestation in non-Bt lines reached 36.70% in 2016 and 45.51% in 2017, even with weekly spraying. An economic analysis revealed that all Bt lines had higher gross returns than their non-Bt isolines. The non-sprayed non-Bt isolines resulted in negative returns in most cases. Maximum fruit yield was obtained from sprayed plots compared to non-sprayed plots, indicating that other insects such as whiteflies, thrips and mites can reduce plant vigor and subsequent fruit weight. Statistically similar densities of non-target arthropods, including beneficial arthropods, were generally observed in both Bt and non-Bt varieties. An additional trial that focused on a single Bt variety and its isoline provided similar results on infestation levels, with and without sprays, and similarly demonstrated higher gross returns and no significant effects on non-target arthropods. Together, these studies indicate that the four Bt brinjal lines are extremely effective at controlling BFSB in Bangladesh without affecting other arthropods, and provide greater economic returns than their non-Bt isolines.

Combined influence of Bt rice and rice dwarf virus on biological parameters of a non-target herbivore, Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae).

The advent of genetically modified (GM) Bt rice creates the possibility of interactions among Bt crops, crop pathogens and non-target herbivores. In particular, information on how pathogen-infected Bt-expressing plants will influence non-target herbivores is necessary to predict the sustainability of GM cropping systems. Laboratory bioassays were conducted to evaluate the potential combined impacts of rice dwarf virus (RDV) and two Bt rice lines, T1C-19 (Cry1C) and T2A-1 (Cry2A), on non-target green rice leafhopper (GRLH), Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae). In the first experiment, GRLHs feeding preference tests on Bt rice lines compared to a parental control rice line, MH63, were conducted. As rice plants were uninfected with RDV, GRLHs generally preferred the control MH63 line over the two Bt lines during the initial 8 h, with no significant preference during the following 64 h. As rice plants were infected with RDV, there were no clear preferences between the Bt rice lines and the control MH63 line. In the second experiment, we assessed the combined influence of RDV-infection status and Bt rice lines on GRLH biological parameters. Egg duration, adult weights, and male adult longevity were significantly affected on RDV-infected Bt rice. Other parameters, egg hatching rate, nymph survival and fecundity were not significantly influenced. We infer that interaction effect among two testing Bt rice lines and RDV will not lead to enlarged pest populations, thus demonstrating that growing these two Bt rice lines will poses negligible risk to GRLH in sustainable rice agroecosystems. Long-term field experiments to monitor the population dynamics of GRLHs at large scale need to be carried out to confirm the current results.

Construction and commissioning of direct beam transport line for PF-AR

PF-AR was constructed as an accumulator ring for TRISTAN, and in the KEKB era it has been revitalized as a 6.5 GeV synchrotron radiation source. The injection energy was 3 GeV and the beam was accelerated to 6.5 GeV prior to the user run. The original beam transport line (BT) from the LINAC to the PF-AR shared its upstream part with the the BT line of KEKB High Energy Ring (HER). The injection-mode change from PF-AR to HER or vice versa needs about 10 minutes for the magnet cycling procedure of the shared part. In SuperKEKB, the upgrade of KEKB, the lifetime of HER is about 10 minutes. The mode-switch operation of the BT is, therefore, not allowed for maintaining the highest luminosity of the SuperKEKB. In order to avoid this problem, a new 6.5 GeV BT line dedicated to PF-AR has been constructed. This also enables the top-up injection for the user run. The commissioning of the new BT line has been completed in this March, and now the first user run has been operated successfully.

Development of Bt Rice and Bt Maize in China and Their Efficacy in Target Pest Control.

Rice and maize are important cereal crops that serve as staple foods, feed, and industrial material in China. Multiple factors constrain the production of both crops, among which insect pests are an important one. Lepidopteran pests cause enormous yield losses for the crops annually. In order to control these pests, China plays an active role in development and application of genetic engineering (GE) to crops, and dozens of GE rice and GE maize lines expressing insecticidal proteins from the soil bacterium Bacillus thuringiensis (Bt) have been developed. Many lines have entered environmental release, field testing, and preproduction testing, and laboratory and field experiments have shown that most of the Bt rice and Bt maize lines developed in China exhibited effective control of major target lepidopteran pests on rice (Chilo suppressalis, Scirpophaga incertulas, and Cnaphalocrocis medinalis) and maize (Ostrinia furnacalis), demonstrating bright prospects for application. However, none of these Bt lines has yet been commercially planted through this writing in 2016. Challenges and perspectives for development and application of Bt rice and maize in China are discussed. This article provides a general context for colleagues to learn about research and development of Bt crops in China, and may shed light on future work in this field.

Expression of an engineered synthetic cry2Aa (D42/K63F/K64P) gene of Bacillus thuringiensis in marker free transgenic tobacco facilitated full-protection from cotton leaf worm (S. littoralis) at very low concentration

Emergence of resistant insects limits the sustainability of Bacillus thuringiensis (Bt) transgenic crop plants for insect management. Beside this, the presence of unwanted marker gene(s) in the transgenic crops is also a major environmental and health concern. Thus, development of marker free transgenic crop plants expressing a new class of toxin having a different mortality mechanism is necessary for resistance management. In a previous study, we generated an engineered Cry2Aa (D42/K63F/K64P) toxin which has a different mortality mechanism as compared to first generation Bt toxin Cry1A, and this engineered toxin was found to enhance 4.1-6.6-fold toxicity against major lepidopteran insect pests of crop plants. In the present study, we have tested the potency of this engineered synthetic Cry2Aa (D42/K63F/K64P) toxin as a candidate in the development of insect resistant transgenic tobacco plants. Simultaneously, we have eliminated the selectable marker gene from the Cry2Aa (D42/K63F/K64P) expressing tobacco plants by exploiting the Cre/lox mediated recombination methodology, and successfully developed marker free T2 transgenic tobacco plants expressing the engineered Cry2Aa toxin. Realtime and western blot analysis demonstrated the expression of engineered toxin gene in transgenic plants. Insect feeding assays revealed that the marker free T2 progeny of transgenic plants expressing Cry2Aa (D42/K63F/K64P) toxin showed 82-92 and 52-61% mortality to cotton leaf worm (CLW) and cotton bollworm (CBW) respectively. Thus, this engineered Cry2Aa toxin could be useful for the generation of insect resistant transgenic Bt lines which will protect the crop damages caused by different insect pests such as CLW and CBW.

MULTI-LOCUS GENOTYPING OF CATTLE GENOMES ON THE BASES OF THE REGION HOMOLOGY TO RETROTRANSPOSONS

Abstract Intensification in livestock has led to necessity of developing methods which allows to es-timate animal genomic breeding values (GBV). In this, an approach was based on identifying asso-ciation of animal production traits’ variability to polymorphism in different genome elements, from microsatellite loci to millions of single nucleotide polymorphisms (SNPs), in genome-wide sequenc-ing. Despite numerous accumulated data, the development of relatively simple, fast and affordable to interpretation methods of polyloci genotyping (genome scan) for assessing breed «gene pool stan-dard» or genomic selection is still actual. The mobile genetic elements, being high polymorphic ge-nomic sites, can serve as anchors in a multi-locus genotyping. The species-specific retrotransposons such as L1_BT LINE which present in the bovine genome with high frequency and the endogenous retrovirus ENV1_BT are of particular interest. In this regard, the aim of this work was the compara-tive analysis of polymorphism in genomic DNA fragments flanked by inverted repeats of nucleotide sequences homologous to fragments of these retrotransposons in genomes of specialized dairy Ayr-shire and Black and White Holstein breeds and the Kalmyk beef breed. A recombination between L1_BT LINE and ENV1_BT we reported earlier turned out to be conservative in studied breeds. This apparently indicated it to be old in appearance. Since the genetic relationships identified from distribution patterns and length polymorphisms of DNA flanked by ENV1_BT inverted repeats dif-fered significantly between specialized dairy breeds and local meat breed but were low variable within the breeds, this allowed to conclude about its relatively low transposition activity. The PIC values (polymorphic information content) for spectra produced in PCR with the endogenous retrovirus ERV1_BT fragment as a primer ranged from 0.075 to 0.089 for studied breeds. Distribution of in-verted repeats homologous to L1_BT was different in character and varied among breeds and within breeds, the PIC values were substantially higher and ranged from 0.062 to 0.260. Thus, the use of multi-locus genotyping of transposable elements is effective for the purposes of animal genetics and breeding but their application depends on transposition activity. Our data showed that the ENV1_BT inverted repeats seem to be convenient marker in genetic differentiation among breeds and revealing «gene pool standard», whereas more transposable L1_BT elements are more relevant in indicating individual variability within a breed. Keywords: multi-locus genotyping, retrotransposons, inverted repeats, genomic scan-ning, breed, cattle.

Arbuscular mycorrhizal fungi colonisation of Cry3 toxin-producing Bt maize and near isogenic maize

Despite the fact that, on average, approximately 5&amp;ndash;6 metric tons/ha of Bt maize stubble enter the soil on more than 170 million of hectares worldwide, the environmental impact of genetically modified maize plants on the arbuscular mycorrhizal fungi (AMF) is poorly known. In this study, the mycorrhizal colonisation on the roots of Bt maize (DAS-59122-7) and its near isogenic line was examined during the whole vegetation period. Cry3 toxin-producing Bt maize and its near isogenic line were grown in an experimental field in Julianna-major, Nagykov&amp;aacute;csi, Hungary. DAS-59122-7 maize produces Cry34Ab1, Cry35Ab1 toxins and pat proteins for herbicide tolerance. The study assessed whether similar arbuscular mycorrhizal colonisation can be observed on the root of the Bt and near isogenic maize line and whether there are any differences in the temporal dynamics of AMF development. The arbuscular, hyphal and the arbuscular mycorrhizal fungi colonisation were higher in the near isogenic line as compared to its Bt counterpart, but no significant effect of the maize line was found as regards vesicle colonisation. The intensity of the arbuscular infection increased over time during plant maturation. DAS-59122-7 Bt maize had a negative effect on the initial development of AMF under field conditions, but no difference was seen in the case of the last two sampling dates (day 82 and 135). The reason of the latter is still not known.

温度和[CO2]升高下转Bt水稻种植对土壤活性碳氮和线虫群落的短期影响

Interactions of global change and transgenic Bt rice( Huahui-1,HH1) cropping on soil ecosystem remain largely unexplored. Here we conducted an OTC( Open Top Chamber) experiment to evaluate the effects of transgenic Bt rice cropping on soil labile organic carbon and nitrogen,and nematode communities under elevation of temperature and [CO2] with two rice varieties including non-Bt rice( MH63) and its transgenic Bt line( HH1). Results showed that( 1) Under the condition of elevated [CO2]and warming,transgenic Bt rice cropping significantly affected the content of soil dissolved organic carbon,dissolved organic nitrogen and NO-3-N. Significantly interactions of transgenic Bt rice,warming and elevated [CO2]were observed for the content of soil dissolved organic carbon and dissolved organic nitrogen. Further,the transgenic Bt rice reduced microbial biomass carbon and nitrogen significantly under ambient temperature and [CO2]; whereaswarming and [CO2]elevation reversed that trend.( 2) At ambient temperatures and[CO2],the total number of nematodes in soil grown with transgenic Bt rice cropping were significantly more than those in soil grown with the parental line. Herbivorous nematodes tended to increase under the condition of warming and elevated [CO2],though not reaching to a significant level. Transgenic Bt rice and warming significantly increased the Nematode Channel Ratio,demonstrating the shift from bacteria-dominated to fungi-dominated energy channel. But [CO2]elevation and transgenic Bt rice significantly increased the nematode Enrichment Index. In conclusion,climate change modified the responses of soil labile organic matter and nematode community to transgenic Bt rice cropping,though it does not lead to negative effects on soil based on the results of short-term experimental duration.

The substantive equivalence of transgenic (Bt and Chi) and non-transgenic cotton based on metabolite profiles

Compositional studies comparing transgenic with non-transgenic counterpart plants are almost universally required by governmental regulatory bodies. In the present study, two T(2) transgenic cotton lines containing chitinase (Line 11/57) and Bt lines (Line 61) were compared with non-transgenic counterpart. To do this, biochemical characteristics of leaves and seeds, including amino acids, fatty acids, carbohydrates, anions, and cations contents of the studied lines were analyzed using GC/MS, high-performance liquid chromatography (HPLC), and ion chromatography (IC) analyzers, respectively. polymerase chain reaction (PCR) and Western blot analyses confirmed the presence and expression of Chi and Bt genes in the studied transgenic lines. Although, compositional analysis of leaves contents confirmed no significant differences between transgenic and non-transgenic counterpart lines, but it was shown that glucose content of chitinase lines, fructose content of transgenic lines (Bt and chitinase) and asparagine and glutamine of chitinase lines were significantly higher than the non-transgenic counterpart plants. Both the transgenic lines (Bt and chitinase) showed significant decrease in the amounts of sodium in comparison to the non-transgenic counterpart plants. The experiments on the seeds showed that histidine, isoleucine, leucine, and phenylalanine contents of all transgenic and non-transgenic lines were the same, whereas other amino acids were significantly increased in the transgenic lines. Surprisingly, it was observed that the concentrations of stearic acid, myristic acid, oleic acid, and linoleic acid in the chitinase line were significantly different than those of non-transgenic counterpart plants, but these components were the same in both Bt line and its non-transgenic counterpart. It seems that more changes observed in the seed contents than leaves is via this point that seeds are known as metabolites storage organs, so they show greater changes in the metabolites contents comparing to the leaves.

Innate and Introduced Resistance Traits in Genetically Modified Aspen Trees and Their Effect on Leaf Beetle Feeding

Genetic modifications of trees may provide many benefits, e.g. increase production, and mitigate climate change and herbivore impacts on forests. However, genetic modifications sometimes result in unintended effects on innate traits involved in plant-herbivore interactions. The importance of intentional changes in plant defence relative to unintentional changes and the natural variation among clones used in forestry has not been evaluated. By a combination of biochemical measurements and bioassays we investigated if insect feeding on GM aspens is more affected by intentional (induction Bt toxins) than of unintentional, non-target changes or clonal differences in innate plant defence. We used two hybrid wildtype clones (Populus tremula x P. tremuloides and Populus tremula x P. alba) of aspen that have been genetically modified for 1) insect resistance (two Bt lines) or 2) reduced lignin properties (two lines COMT and CAD), respectively. Our measurements of biochemical properties suggest that unintended changes by GM modifications (occurring due to events in the transformation process) in innate plant defence (phenolic compounds) were generally smaller but fundamentally different than differences seen among different wildtype clones (e.g. quantitative and qualitative, respectively). However, neither clonal differences between the two wildtype clones nor unintended changes in phytochemistry influenced consumption by the leaf beetle (Phratora vitellinae). By contrast, Bt induction had a strong direct intended effect as well as a post experiment effect on leaf beetle consumption. The latter suggested lasting reduction of beetle fitness following Bt exposure that is likely due to intestinal damage suffered by the initial Bt exposure. We conclude that Bt induction clearly have intended effects on a target species. Furthermore, the effect of unintended changes in innate plant defence traits, when they occur, are context dependent and have in comparison to Bt induction probably less pronounced effect on targeted herbivores.