Conventional Isoline Research Articles

Biochemical analyses demonstrate that Bt maize has no adverse effects on Eisenia fetida.

The potential effects of Bt (Bacillus thuringiensis) maize on non-target organisms should be evaluated before such maize is commercially planted. Earthworms play an indispensable role in the soil ecosystem; act as important bio-indicators of soil quality and environmental pollution. Therefore, earthworms are often used as the object to evaluate the non-target effect of Bt maize. To accelerate the commercialization of transgenic maize in China, a 90-day Eisenia fetida feeding experiment was conducted to evaluate the potential effects of Bt maize line, BT799—which was developed by China Agricultural University and contains the Cry1Ac gene—and its non-Bt conventional isoline—Zheng 58—on E. fetida. Our results showed that the Bt maize line had no significant effects on the growth, reproduction, or enzymatic activities of these earthworms. In summary, Bt maize had no toxic effects on E. fetida.

Toxicological and biochemical analyses demonstrate no toxic effect of Bt maize on the Folsomia candida.

The potential effects of Bt (Bacillus thuringiensis) maize on non-target organisms must be conducted before the Bt maize is commercially planted. Folsomia candida is one of the non-target organisms of Bt maize, also as an important indicator of soil quality and environmental pollution. In this study, a 90-day F. candida feeding test were conducted to evaluate the potential effects of two Bt maize lines IE09S034 and BT799 and their non-Bt conventional isolines Zong 31 and Zheng 58. The results show that Bt maize lines had no significant effects on the survival rate, reproduction, adult body length, larval body length, and the activities of acetyl cholinesterase, catalase and superoxide dismutase on the F. candida. Namely, Bt maize had no toxic effects on the F. candida.

Biological parameters of Spodoptera cosmioides Walker (Lepidoptera: Noctuidae) in cotton varieties

ABSTRACT: Spodoptera cosmioides Walker is a polyphagous insecticide-resistant species found in various regions of Brazil. Despite occurring at low densities, it is considered a potential pest of cotton, soybean, and bean crops in the Brazilian cerrado. This work investigated the comparative biology of S. cosmioides in the commercial transgenic cotton NuOPAL (Bollgard I, Evento 531) and the conventional isoline variety DeltaOPAL. The experiment was conducted under laboratory conditions (26 ± 1°C; relative humidity: 70 ± 10%; photoperiod: 12h), using newly-hatched and individualized larvae. We evaluated the duration and viability of immature stages, duration of the biological cycle, pupal weight, sex ratio, percentage of deformed adults and of adults trapped in the pupal case, adult longevity, fecundity, and egg viability. The biological parameters observed showed no significant differences between the two varieties studied, which enabled high consumption, high assimilation, high fecundity, and viability for S. cosmioides.

Species Richness and Community Composition of Ants and Beetles in Bt and non-Bt Maize Fields

Insect-resistant genetically modified (GM) plants have been cultivated in several countries on a large scale. These plants express the Cry toxins from the bacterium Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt), which confers target-pest resistance to plants. Studies on the effects of GM plants on nontarget organisms are important to assess the technology's impact on biodiversity. The objective of this study was to determine whether there are differences in the species richness and composition of ants and ground beetles in Bt maize (four different toxins: Cry1Ab, Cry1F, and Cry1A.105/Cry2Ab2) and conventional isoline (non-Bt) fields, in the first (summer) and second (winter) cropping seasons in 13 localities of Mato Grosso do Sul State, Brazil, over a 2-yr period (2009-2011). The assessment of Coleoptera and Formicidae species was performed using pitfall traps placed in fields throughout the period of vegetative growth and maturation of plants. Data were analyzed using faunistic indices of species richness, ordination by nonmetric multidimensional scaling, and multivariate analysis of variance. No statistically significant difference was found in the species richness of ant and ground beetle communities when comparing sites of Bt with those of non-Bt maize. Overall, Bt technology did not affect the composition of ant and ground beetles; however, municipality and cropping season exerted influence on the beetle composition. Some species were only observed in the first crop, whereas others were only observed in the second crop. This research suggests that Bt maize does not affect ant and ground beetle populations differently from its isoline.

Toxicological and Biochemical Analyses Demonstrate the Absence of Lethal or Sublethal Effects of cry1C- or cry2A-Expressing Bt Rice on the Collembolan Folsomia candida.

Assessing the potential effects of insect-resistant genetically engineered (GE) plants on collembolans is important because these common soil arthropods may be exposed to insecticidal proteins produced in GE plants by ingestion of plant residues, crop pollen, or root exudates. Laboratory studies were conducted to evaluate the potential effects of two Bacillus thuringiensis (Bt)-rice lines expressing Cry1C and Cry2A in pollen and leaves and of their non-Bt conventional isolines on the fitness of the collembolan Folsomia candida and on the activities of its antioxidant-related enzymes, superoxide dismutase and peroxidase, and of its detoxification-related enzymes, glutathione reductase and glutathione S-transferase. Survival, development, reproduction, and the intrinsic rate of increase (rm) were not significantly reduced when F. candida fed on the Bt rice pollen or leaf powder than on the non-Bt rice materials; these parameters, however, were significantly reduced when F. candida fed on non-Bt rice pollen or non-Bt leaf-based diets containing the protease inhibitor E-64 at 75 μg/g. The activities of the antioxidant-related and detoxification-related enzymes in F. candida were not significantly affected when F. candida fed on the Bt rice materials, but were significantly increased when F. candida fed on the non-Bt rice materials containing E-64. The results demonstrate that Cry1C and Cry2A are not toxic to F. candida, and also indicate the absence of unintended effects on the collembolan caused by any change in plant tissue nutritional composition due to foreign gene transformation.

Seleção de sementes de soja geneticamente modificadas com o gene marcador bar por meio do teste de germinação em solução de glufosinato de amônio

The objective of this work was to identify promising GM events in a fast and practical manner, in replacement of methodologies based in aerial pulverization in greenhouse and conventional PCR. Eight GM events and their respective conventional isolines were used. Germination and seedling length tests were performed on a paper soaked in an herbicide solution and in the control conditions. To compare the method efficiency, greenhouse tests were carried out, in which the herbicide was applied to plants in the V3 stage. Results obtained indicated that events 2Ia4, 2Oa4, 5Ha10, and 1Ea2939 showed resistance phenotype in both germination and seedling length tests, as well as in plants in the V3 developmental stage. Some GM events (2Ha11, 2Ia1, 3Pa4 and 1Ea15), even with the confirmation of gene bar, were sensible to herbicide. The differences observed in the resistance phenotype of the different GM lineages may be associated with variations in the level of expression of the bar gene, which may vary depending on the insertion position in the host genome. It was possible to conclude that the use of germination and seedling length tests in paper was efficient for selecting GM plants with confirmed results in tests performed in greenhouse with adult plants, showing to be a fast, cheap, and practical methodology, applicable in an early stage, accelerating the screening of promising plants in breeding programs.

Susceptibility of Genetically Modified Maize Hybrids to Sugarcane Borer,Diatraea saccharalis(F.), at Sinaloa, Mexico

Use of genetically modified hybrids of maize, Zea mays L., is a pest management tool with special significance when a pest such as sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), becomes less responsive to conventional control methods. Resistance of genetically modified maize hybrids ‘AgrisureTM 3000 GT’ and ‘Agrisure® VipteraTM 3111’ were evaluated against stalk borers and compared with conventional hybrids with or without insecticide. During evaluation, few borers were found, especially during the first year (2012), but, in most cases, stalk damage by larvae was less in AgrisureTM 3000 GT and Agrisure® VipteraTM 3111 than in their conventional isolines. Insecticide did not prevent damage by the pest and even treated conventional maize was damaged. Use of AgrisureTM 3000 GT and Agrisure® VipteraTM 3111 hybrids can be a management tool to prevent damage by sugarcane borer in maize.

Chemical properties and water absorption kinetics of transgenic corn grain (2B587 Hx) and its conventional isoline (2B587)

In the hydration process, besides influencing processing conditions, the cultivar may also influence water absorption by the grains and, consequently, yield and quality of the milled products. Therefore, the moisture absorption kinetics of the transgenic corn grain 2B587 Hx and its conventional isoline 2B587 were studied, as well as the chemical characterization of the samples in natural conditions. The water absorption kinetics of the grains was modeled using Peleg's equation at hydration temperatures of 40, 50, 60, and 67 °C. The 2B587 Hx transgenic corn, compared with the 2B587 conventional corn, had higher carbohydrate and ash contents and lower crude fiber content. The water absorption by the grains, which was satisfactorily represented by Peleg's model, occurred more quickly as the temperature increased. Peleg's constant, k1, which is inversely related to the initial hydration rate, varied from 405.2 to 141.5 min g/g for conventional corn and from 429.5 to 149.5 min g/g for transgenic corn at temperatures from 40 to 67 °C. The choice of the cultivar may depend on the specifications required by the industry for the main final products.

Development of Dichelops melacanthus and its egg parasitoid Telenomus podisi reared on Bt-soybean MON 87701 x MON 89788 and its near conventional isoline under different temperatures.

Dichelops melacanthus was studied under controlled conditions (60 ± 10% RH and 14/10 h L/D photoperiod), and three constant temperatures (19, 25, and 31 ± 2 °C). Fresh pods of MON 87701 × MON 89788 soybeans and its near non-Bt isoline (A5547) were supplied to nymphs and adults. The biology of T. podisi was studied in the same controlled RH conditions, but only at the standard temperature of 25 ± 2 °C. Overall, the development of D. melacanthus was better at higher temperatures, which accelerated the development of the stink bug without affecting adult biological parameters. No influence of Bt-soybeans on the biology of the pest was observed in any temperature studied, which shows that D. melacanthus is not affected by this transgenic soybean. The egg parasitoid T. podisi also was not harmed when it parasitized eggs of the pest fed with MON 87701 × MON 89788 soybeans, with similar results to those obtained in non-Bt isogenic soybeans. Thus, this study demonstrates that D. melacanthus is favored at high temperatures (31 ± 2 °C), and that neither did MON 87701 × MON 89788 soybean pods affect the development of the pest nor its parasitoid T. podisi.

English

This study evaluated the symptoms of attack by the green belly stink bug, Dichelops melacanthus (Dallas, 1851), in conventional and transgenic commercial corn ( Zea mays ) hybrids, the seeds of which were either treated using the insecticide thiamethoxam or without chemical treatment. The experiment was conducted during the 2010/2011 crop season in Pindorama, Sao Paulo State, Brazil. The percentage of plants with symptoms or injuries was recorded by visually evaluating the degree or intensity of attack symptoms. The height of the plants was also recorded on a weekly basis, until the plants were 40 DAE. We also measured yield compounds, such as the number of rows of grain/spikes, spike weight (with and without straw), and grain weight. The seeds of hybrids that had previously been treated with thiamethoxam showed lower percentage of the number of plants that were attacked. Further, the grain weight of the plants increased 29.5% more than that of plants from untreated seeds. It was also found that transgenic hybrids exhibited lower height reduction in 40 DAE plants than did conventional isolines. Visual inspection is effective in assessing the degree of injury caused by attacks to the developing plants.

Parâmetros biológicos da lagarta falsa-medideira em cultivares de algodoeiro com as proteínas Cry1Ac e Cry1F

O objetivo deste trabalho foi avaliar os efeitos de cultivares transgênicas de algodoeiro que expressam as proteínas Cry1Ac e Cry1F, nos parâmetros biológicos da lagarta falsa-medideira (Chrysodeixis includens). Lagartas neonatas foram alimentadas durante toda a fase larval com folhas de cultivares transgênicas e de suas isolinhas convencionais. Na cultivar Nuopal (Bollgard I) (Cry1Ac), 62% das lagartas sobreviveram e se transformaram em pupas normais. A cultivar FM 975 (WideStrike) (Cry1Ac e Cry1F) é letal para lagartas de primeiro instar, com 100% de mortalidade.

Biological characteristics of Heliothis virescens fed with Bt-soybean MON 87701 × MON 89788 and its conventional isoline

This study aimed to evaluate the larval biology of Heliothis virescens in soybean MON 87701 x MON 89788 and its isogenic non-Bt. In general, the impact of soybean MON 87701 x MON 89788 on H. virescens was evidenced in all bioassays, 100% larval mortality, independent of the structure (leaf or pod) consumed by the pest. The small larvae (1st and 3rd instar) demonstrated that they were unable to damage fresh pods of soybean, regardless of whether Bt or not Bt. The large larvae (5th instar) fed on soybean MON 87701 x MON 89788 soybeans consumed three times less compared to larvae fed on non-Bt soybeans, and resulted in reduced longevity and larval survival. When soybean plants were infested with 5th instar larvae, H. virescens caused injuries in the steams of the conventional soybean. It was recorded that the insects moves quickly to this region of the plant. However the soybean MON 87701 x MON 89788 was an effective tool in controlling H. virescens.

Decrease in catalase activity of Folsomia candida fed a Bt rice diet

Here we report the effects of three Bt-rice varieties and their non- Bt conventional isolines on biological traits including survival, reproduction, and the activities of three antioxidant enzymes superoxide dismutase, catalase and peroxidase, in the Collembolan, Folsomia candida. The reproduction was significantly lower when fed Kemingdao and Huahui1 than those feeding on their non-GM near-isogenic varieties Xiushui and Minghui63 respectively, this can be explained by the differences of plant compositions depended on variety of rice. The catalase activity of F. candida was significantly lower when fed the Bt-rice variety Kemingdao compared to the near-isogenic non- Bt-rice variety Xiushui. This suggests that some Bt-rice varieties may impose environmental stress to collembolans. We emphasize that changes in activity of antioxidant enzymes of non-target organisms are important in understanding the ecological consequences for organisms inhabiting transgenic Bt-rice plantations.