Transgenic Genotypes Research Articles

Utilizing MIKC-type MADS-box protein SOC1 for yield potential enhancement in maize

Key messageOverexpression of Zea mays SOC gene promotes flowering, reduces plant height, and leads to no reduction in grain production per plant, suggesting enhanced yield potential, at least, through increasing planting density.MIKC-type MADS-box gene SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) is an integrator conserved in the plant flowering pathway. In this study, the maize SOC1 (ZmSOC1) gene was cloned and overexpressed in transgenic maize Hi-II genotype. The T0 plants were backcrossed with nontransgenic inbred B73 to produce first generation backcross (BC1) seeds. Phenotyping of both transgenic and null segregant (NT) BC1 plants was conducted in three independent experiments. The BC1 transgenic plants showed new attributes such as increased vegetative growth, accelerated flowering time, reduced overall plant height, and increased grain weight. Second generation backcross (BC2) plants were evaluated in the field using two planting densities. Compared to BC2 NT plants, BC2 transgenic plants, were 12–18% shorter, flowered 5 days earlier, and showed no reduction in grain production per plant and an increase in fat, starch, and simple sugars in the grain. Transcriptome comparison in young leaves of 56-day-old BC1 plants revealed that the overexpressed ZmSOC1 resulted in 107 differentially expressed genes. The upregulated transcription factor DNA BINDING WITH ONE FINGER 5.4 (DOF5.4) was among the genes responsible for the reduced plant height. Modulating expression of SOC1 opens a new and effective approach to promote flowering and reduce plant height, which may have potential to enhance crop yield and improve grain quality.

Natural hybridization between transgenic and wild soybean genotypes

Natural hybridization between transgenic and wild soybean genotypes

Response of Citrus spp. germplasm from Puerto Rico grafted on two rootstocks to early infection of huanglongbing

Huanglongbing (HLB), associated with the proteobacterium ‘Candidatus Liberibacter asiaticus’(CLa), is a destructive disease in citrus. Resistance/tolerance has been identified in some citrus species, wild relatives, and transgenic citrus genotypes. The objectives of this study were to: (1) evaluate the response of the citrus germplasm collection from Puerto Rico (namely ‘Rico’) to HLB, (2) determine the most appropriate rootstock-genotype combination, and (3) quantify the presence of the bacterium in the plant tissue by quantitative polymerase chain reaction (qPCR). Seventeen genotypes were grafted onto ‘HRS 812’ and ‘Swingle’ citrumelo rootstocks. The plants were inoculated with HLB infected buds and evaluated at 12 months after inoculation in a greenhouse in Adjuntas, Puerto Rico. The genotypes ‘Lares’ and ‘Padilla’ had significantly higher incidence (>65.0%) and severity (3.2–4.3) compared to ‘Mexican Lime’ and ‘Tahiti Lime’ that had lower scores (<18.0%, 1.1–1.3) using both rootstocks. In contrast, the genotypes ‘Fronton’, ‘PR-Sel-1’, and ‘Rico 7–376’ grafted on HRS 812; and ‘Pietri 334’ grafted on Swingle citrumelo had lower HLB incidence (<10%) and severity (<1.5). Significantly higher mean cycle threshold (Ct) values were only observed for the genotypes Fronton (37.0), Tahiti Lime (36.5), and Pietri 334 (36.2) compared to Padilla (34.7 and 32.7 when HRS 812 and Swingle citrumelo was used as rootstock, respectively). Citrus genotypes having lower HLB scores were identified, however, their reaction varied according to the rootstock used.

Dissecting the Roles of Cuticular Wax in Plant Resistance to Shoot Dehydration and Low-Temperature Stress in Arabidopsis.

Cuticular waxes are a mixture of hydrophobic very-long-chain fatty acids and their derivatives accumulated in the plant cuticle. Most studies define the role of cuticular wax largely based on reducing nonstomatal water loss. The present study investigated the role of cuticular wax in reducing both low-temperature and dehydration stress in plants using Arabidopsis thaliana mutants and transgenic genotypes altered in the formation of cuticular wax. cer3-6, a known Arabidopsis wax-deficient mutant (with distinct reduction in aldehydes, n-alkanes, secondary n-alcohols, and ketones compared to wild type (WT)), was most sensitive to water loss, while dewax, a known wax overproducer (greater alkanes and ketones compared to WT), was more resistant to dehydration compared to WT. Furthermore, cold-acclimated cer3-6 froze at warmer temperatures, while cold-acclimated dewax displayed freezing exotherms at colder temperatures compared to WT. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis identified a characteristic decrease in the accumulation of certain waxes (e.g., alkanes, alcohols) in Arabidopsis cuticles under cold acclimation, which was additionally reduced in cer3-6. Conversely, the dewax mutant showed a greater ability to accumulate waxes under cold acclimation. Fourier Transform Infrared Spectroscopy (FTIR) also supported observations in cuticular wax deposition under cold acclimation. Our data indicate cuticular alkane waxes along with alcohols and fatty acids can facilitate avoidance of both ice formation and leaf water loss under dehydration stress and are promising genetic targets of interest.

Wheat MADS-box gene TaSEP3-D1 negatively regulates heading date

The MADS-box gene plays an important role in regulating plant growth and development. In this study, a SEP3-like MADS-box gene TaSEP3-1 was isolated from bread wheat. The expression patterns of the three homoeologs TaSEP3-A1, TaSEP3-B1, and TaSEP3-D1 were similar, and higher expression levels were detected in floral organs and developing kernels. TaSEP3-D1 was located in the nucleus and cytoplasm and possessed transactivation activity in yeast. Homoeolog sequence polymorphism analysis identified four, three, and four haplotypes of TaSEP3-A1, TaSEP3-B1, and TaSEP3-D1, respectively, and the haplotypes of TaSEP3-D1 had larger effects on agronomic traits than those of TaSEP3-A1 and TaSEP3-B1. D1_h4, significantly associated with heading date, plant height, and other yield-related traits, was the favored haplotype of TaSEP3-D1. Transgenic wheat genotypes overexpressing TaSEP3-D1 exhibited delayed heading and reduced plant height, indicating a role in regulating heading date and plant development. These results shed light on the role of TaSEP3-D1 in wheat plant development. The favored haplotype of TaSEP3-D1 can be applied in breeding to improve plant architecture and yield in wheat.

Treatment With FoxP3+ Antigen-Experienced T Regulatory Cells Arrests Progressive Retinal Damage in a Spontaneous Model of Uveitis.

We specify the clinical features of a spontaneous experimental autoimmune uveitis (EAU) model, in which foreign hen-egg lysozyme (HEL) is expressed in the retina, controlled by the promoter for interphotoreceptor retinol binding protein (IRBP). We previously reported 100% P21 (post-partum day) IRBP:HEL single transgenic (sTg) mice, when crossed to transgenic T cell receptor mice (3A9) generating the double transgenic (dTg) genotype, develop EAU despite profound lymphopenia (thymic HEL-specific T cell deletion). In this work, we characterized the immune component of this model and found conventional dTg CD4+ T cells were less anergic than those from 3A9 controls. Furthermore, prior in vitro HEL-activation of 3A9 anergic T cells (Tan) rendered them uveitogenic upon adoptive transfer (Tx) to sTg mice, while antigen-experienced (AgX, dTg), but not naïve (3A9) T cells halted disease in P21 dTg mice. Flow cytometric analysis of the AgX cells elucidated the underlying pathology: FoxP3+CD25hiCD4+ T regulatory cells (Treg) comprised ∼18%, while FR4+CD73+FoxP3-CD25lo/–CD4+ Tan comprised ∼1.2% of total cells. Further Treg-enrichment (∼80%) of the AgX population indicated FoxP3+CD25hiCD4+ Treg played a key role in EAU-suppression while FoxP3-CD25lo/–CD4+ T cells did not. Here we present the novel concept of dual immunological tolerance where spontaneous EAU is due to escape from anergy with consequent failure of Treg induction and subsequent imbalance in the [Treg:Teffector] cell ratio. The reduced numbers of Tan, normally sustaining Treg to prevent autoimmunity, are the trigger for disease, while immune homeostasis can be restored by supplementation with AgX, but not naïve, antigen-specific Treg.

Elucidating the role of polygalacturonase genes in strawberry fruit softening.

To disentangle the role of polygalacturonase (PG) genes in strawberry softening, the two PG genes most expressed in ripe receptacles, FaPG1 and FaPG2, were down-regulated. Transgenic ripe fruits were firmer than those of the wild type when PG genes were silenced individually. Simultaneous silencing of both PG genes by transgene stacking did not result in an additional increase in firmness. Cell walls from ripe fruits were characterized by a carbohydrate microarray. Higher signals of homogalacturonan and rhamnogalacturonan I pectin epitopes in polysaccharide fractions tightly bound to the cell wall were observed in the transgenic genotypes, suggesting a lower pectin solubilization. At the transcriptomic level, the suppression of FaPG1 or FaPG2 alone induced few transcriptomic changes in the ripe receptacle, but the amount of differentially expressed genes increased notably when both genes were silenced. Many genes encoding cell wall-modifying enzymes were down-regulated. The expression of a putative high affinity potassium transporter was induced in all transgenic genotypes, indicating that cell wall weakening and loss of cell turgor could be linked. These results suggest that, besides the disassembly of pectins tightly linked to the cell wall, PGs could play other roles in strawberry softening, such as the release of oligogalacturonides exerting a positive feedback in softening.

Breaking the Summer Dormancy of Pinellia ternata by Introducing a Heat Tolerance Receptor-Like Kinase ERECTA Gene.

Pinellia ternata is a perennial traditional Chinese medicinal plant that undergoes different phenological patterns of dormancy depending on where it is growing. Plants grown in central and southern China typically display two growth cycles every year before and after hot summer days, exhibiting a summer dormancy. However, germplasms from these areas do not go into a dormancy phase in northern China where the summer monthly average temperatures range from 29–31°C. The northern China herbal growers prefer plant stocks from central China due to their longer growing quality and better tuber harvests. Here, we introduced a heat responsive receptor-like kinase ERECTA (ER) gene into P. ternata to explore changes in the growth cycle which were aimed at disrupting the summer dormancy. The 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene was also co-transformed with ER to improve the commercial trait. For the thermo-tolerance evaluation, all plants were treated with high temperatures (35°C/40°C) in a growth chamber or grown in natural field temperature in an isolated field before measurement of different agricultural, biochemical and physiological traits. The transgenics showed significantly (P < 0.05) higher heat tolerance, maintaining healthy vegetative growth unlike the empty vector (EV) harboring controls that became chlorotic and necrotic. Better performance in some of the monitored physiological traits was evident for overexpression lines exposed to the heat stress. In open isolated field trials, the transgenic genotypes did not show a summer dormancy but had a survival rate of 84–95%. The tuber biomasses were also significantly (P < 0.05) higher for the transgenic lines as compared to the EV controls, except for line ER118. Metabolites analysis indicated that the HMGR overexpressing lines (HMGR orHMGR + ER) exhibited significantly higher amounts of bioactive compounds including aromadendrene-4, 10-diol and 4, 8, 13-cyclotetradecatriene-1, 3-diol, 1, 5, 9-trimethyl-12-(1-methylethyl). Our findings show that the summer dormancy of P. ternata which is a naturally evolved trait, can be removed by a single heat responsive gene. The study contributes to generating heat tolerant new Pinellia varieties with enhanced commercially valuable chemicals.

TRAP Markers Allow the Identification of Transgenic Lines that are Genetically Close to Their Parental Genotype

Molecular markers could be used to screen for somaclonal variation during the process of genetic transformation. We aimed to test target region amplified polymorphism (TRAP) marker to quickly predict similarity to the parental line of different transgenic lines. DNA of transgenic lines, wild-type genotypes and additional sugarcane clones was genotyped with TRAP markers. Amplification products were separated by electrophoresis on polyacrylamide denaturing gels, images were analyzed, and bands were transformed into a 0/1 matrix. Similarity was calculated using the Jaccard coefficient and dendrograms generated using UPGMA analysis. TRAP was initially used to determine whether the close growth resemblance between six herbicide-tolerant lines and their parental cultivar RA87-3 was also true at the genetic level. The genetic characterization confirmed the preliminary phenotypic evaluations since transformed lines exhibited none or only minor genetic changes whereas lines with growth aberrations also included in the analysis showed a significant degree of polymorphism. The incorporation of other genotypes as controls allowed us to internally evaluate the accuracy of the survey ensuring that a significant number of polymorphic bands were analyzed. These markers were routinely applied to evaluate transgenic lines of LCP85-384, TUCCP77-42, TUC95-10 and TUC03-12 at early stages of the characterization process. Our results showed that the use of TRAP markers is a rapid and recommendable first approach to identify transformed plants that are genetically close to their parental genotype as they could be applied at the early stages of evaluation to select for the most valuable lines to carry out field tests.

Field trial evidence of non-transgenic and transgenic Bt. rice genotypes in north of Iran

BackgroundField-testing genetically modified crops provides scientists with an opportunity to collect information on environmental interactions and agronomic performance, which is critical to a full environmental safety assessment as required by regulatory authorities. As a result, the goal of this research was field trial of transgenic and conventional rice genotypes. The experiment was carried out in a randomized complete blocks design (RCBD) with four replications and seven genotypes in three isolated regions under the biosafety standard protocol in north of Iran in 2016. In this study, four transgenic lines with an active cry1Ab gene in the vegetative stage and three conventional genotypes (control) as treatment were assessed. ResultsThe findings demonstrated that in all three regions, transgenic lines derived from Khazar cultivar, were similar to their parent(s) in terms of growth phenology, agronomical traits, grain amylose content, gel consistency, and gelatinization temperature. In all the three regions, the highest number of panicle per m2, number of filled spikelet per panicle, and filled spikelet percentage per panicle were obtained for transgenic lines. Khazar cultivar compared to the transgenic lines showed lower paddy yield. In all the three regions, transgenic lines had lower yield loss than their non-transgenic parent. The lowest number of white heads belonged to transgenic Tarom Molaii and transgenic lines. The most positive direct effect on paddy yield was related to the number of filled spikelet per panicle. Thus, this can be a good trait to achieve higher yield derived from reducing the negative indirect effect of dead heart and white heads. ConclusionIt can be concluded that by producing transgenic rice, which is resistant to stem borer with an active promoter in the reproductive stage, farmers can reduce significant part of yield loss resulting from dead heart and white heads directly correlating with the number of filled spikelet per panicle and paddy yield.

Interaction between Corn Genotypes with Bt Protein and Management Strategies for Spodoptera frugiperda (Lepidoptera: Noctuidae)

Insect pests, including caterpillars, cause losses in maize (Zea mays L.; Poaceae) which is one of the most important agricultural crops in the world. The objective of this study was to evaluate the management of Spodoptera frugiperda Smith & Abbot (Lepidoptera: Noctuidae) with transgenic and conventional maize genotypes. The experiments were conducted in the field in summer crops from the seasons 2014/2015 and 2015/2016 in a randomized complete block design with sub-subdivided plots represented by: control (no control), chemical control (methomyl + diflubenzurom), Integrated Pest Management–spinosade, and biological control (Trichogramma pretiosum Riley; Hymenoptera: Trichogrammatidae) with 3 maize genotypes (Impact VIP 3, P3862 HX, and BM 3061) and 4 replications. Control and reduction of S. frugiperda damage were higher in the Impact VIP 3 corn genotype. The crop yield was higher (11,838.59 kg per h-1), and the damage to the ears was lower in the biological control with T. pretiosum.

Harvesting and post-harvest management for improving seed quality and subsequent crop yield of cotton

Quality seed is a prerequisite to uniform stand establishment, which contributes to higher crop yield. However, prevalence of poor-quality cottonseed with high moisture content due to suboptimal harvesting and postharvest practices is the primary reason for crop-stand failure in developing countries. The present study evaluated the effects of harvesting environment, drying method and storage conditions on seed quality of transgenic (FH-142) and non-transgenic (FH-942) genotypes of cotton (Gossypium hirsutum L.) cultivated in Pakistan. Both genotypes were picked three times at monthly intervals during the cropping season and subjected to a ginning process. Seed was then dried in the sun or with desiccant zeolite beads, and stored for 5 months in cloth or hermetic bags at room temperature or in paper bags at 10°C. The efficiency of storage systems was evaluated by estimating moisture content and germination potential periodically in the storehouse and later under field conditions. Both genotypes exhibited better seed quality attributes at the first picking, and zeolite beads dried seed to lowest moisture content more quickly than sun-drying. Seeds of both genotypes stored hermetically retained the lowest moisture content, maximum germination potential, and lower fatty acid contents throughout the storage period, as well as performing significantly better in the field by exhibiting early and uniform stand establishment, more fruiting branches and bolls, and higher yield. Thus, use of zeolite beads in post-harvest drying followed by hermetic storage preserves cottonseed quality for longer, and leads to improved crop growth and yield of cotton. These practices will be useful for cotton farmers in developing countries.

Expression of short hairpin RNA (shRNA) targeting AC2 gene of Mungbean yellow mosaic India virus (MYMIV) reduces the viral titre in soybean

Mungbean yellow mosaic India virus (MYMIV) belonging to the family Geminiviridae and the genus Begomovirus is a severe pathogen of tropical legumes including soybean. The absence of genetically mapped loci conferring resistance together with the genetic diversity of begomoviruses infecting soybean warrants the utilization of RNA interference (RNAi) technology to develop virus resistance. However, viral suppressors of RNAi (VSRs) reduce the effectiveness of RNA silencing. Here, we report the effectiveness of Agrobacterium-mediated transient expression of shRNA, targeting a conserved region of AC2 ORF (a VSR) of MYMIV, in conferring virus resistance in soybean. Transient expression of shRNA showed progressive reduction of the viral titre estimated by the MYMIV-derived AC2 gene copy numbers from the initial inoculum by approximately 80-fold 20days post-application. In addition, the newly emerging leaves exhibited symptom recovery. Thus, this study proves that AC2 of MYMIV is a potent target gene for obtaining RNAi-mediated virus resistance in soybean. Agro-infiltration-based delivery of shRNA was an efficient means of gene silencing and could pave way for the development of transgenic virus-resistant soybean genotype.

Arabidopsis and sunflower plants with increased xylem area show enhanced seed yield.

Plant architecture plasticity determines the efficiency at harvesting and plays a major role defining biomass and seed yield. We observed that several previously described transgenic genotypes exhibiting increased seed yield also show wider stems and more vascular bundles than wild-type plants. Here, the relationship between these characteristics and seed yield was investigated. Hanging weight on the main stem of Arabidopsis plants provoked significant stem widening. Such widening was accompanied by an increase in the number of vascular bundles and about 100% of yield increase. In parallel, lignin deposition diminished. Vascular bundle formation started in the upper internode and continued downstream. AUX/LAX carriers were essential for this response. The increase of vascular bundles was reverted 3 weeks after the treatment leading to an enlarged xylem area. Aux1, lax1, and lax3 mutant plants were also able to enlarge their stems after the treatment, whereas lax2 plants did not. However, none of these mutants exhibited more vascular bundles or seed yield compared with untreated plants. Weight-induced xylem area enhancement and increased seed yield were also observed in sunflower plants. Altogether these results showed a strong correlation between the number of vascular bundles and enhanced seed yield under a long-day photoperiod. Furthermore, changes in the levels of auxin carriers affected both these processes in the same manner, suggesting that there may be an underlying causality.

Mechanism of the drought tolerance of a transgenic soybean overexpressing the molecular chaperone BiP.

Drought is one of major constraints thatlimits agricultural productivity. Some factors, including climate changes andacreage expansion, indicates towards the need for developing drought tolerant genotypes. In addition to its protective role against endoplasmic reticulum (ER) stress, we have previously shown that the molecular chaperone binding protein (BiP) is involved in the response to osmotic stress and promotes drought tolerance. Here, we analyzed the proteomic and metabolic profiles of BiP-overexpressing transgenic soybean plants and the corresponding untransformed line under drought conditions by 2DE-MS and GC/MS. The transgenic plant showed lower levels of the abscisic acid and jasmonic acid as compared to untransformed plants both in irrigated and non-irrigated conditions. In contrast, the level of salicylic acid was higher in transgenic lines than in untransformed line, which was consistent with the antagonistic responses mediated by these phytohormones. The transgenic plants displayed a higher abundance of photosynthesis-related proteins, which gave credence to the hypothesis that these transgenic plants could survive under drought conditions due to their genetic modification and alteredphysiology.The proteins involved in pathways related to respiration, glycolysis and oxidative stress were not signifcantly changed in transgenic plants as compared tountransformed genotype, which indicate a lower metabolic perturbation under drought of the engineered genotype. Thetransgenic plants may have adopted a mechanism of drought tolerance by accumulating osmotically active solutes in the cell. As evidenced by the metabolic profiles, the accumulation of nine primary amino acids by protein degradation maintained the cellular turgor in the transgenic genotype under drought conditions. Thus, this mechanism of protection may cause the physiological activities including photosynthesis to be active underdrought conditions.

Prevalence of the major pests in transgenic and non-transgenic cotton genotype in response to climatic factors and their impact on yield

The incidence of insect pests in cotton crop, such as Bemisia tabaci, Amrasca devastans and Pectinophora gossypiella (PBW) is dependent on climatic factors, such as maximum and minimum temperature, relative humidity and rainfall. Besides, cotton leaf curl disease (CLCuD) is also a major yield-limiting factor in the cotton crop. The results indicated that non-transgenic genotypes were heavily infested by whitefly, whereas jassid infested all genotypes with little difference. The population of whitefly and jassid acquired peak level in the month of July and August on all the genotypes. The correlation studies indicated the negative correlation of jassid, pink bollworm and CLCuD on yield component, whereas whitefly infestation was found positively correlated with CLCuD. Moreover, multivariate regression analysis (MRA) indicated the maximum and minimum temperature impacted the infestation of whitefly and jassid more than other factors, whereas maximum temperature greatly impacted the infestation of PBW in transgenic genotypes.

Breeding for provitamin A biofortification of maize (Zea mays L.)

AbstractVitamin A deficiency is widely prevailing in children and women of developing countries. Deficiency of vitamin A causes night blindness, growth retardation, xerophthalmia and increases the susceptibility against epidemic diseases. Among different interventions of overcoming malnutrition, biofortification is the most acceptable and preferred intervention among researchers, growers and consumers. Maize is grown and consumed in those regions where vitamin A deficiency is most prevalent; thus, targeting this crop for provitamin A biofortification is the most appropriate solution. Different breeding strategies including diversity analysis, introduction and stability analysis of exotic germplasm, hybridization, heterosis breeding, mutagenesis and marker‐assisted selection are practised for exploring maize germplasm and development of provitamin A‐enriched cultivars. Genome‐wide association selection and development of transgenic maize genotypes are also being practised, whereas RNA interference and genome editing tools could also be used as potential strategies for provitamin A biofortification of maize genotypes. The use of these breeding strategies for provitamin A biofortification of maize is comprehensively reviewed to provide a working outline for maize breeders.

Caracterización de indicadores de la calidad del fruto en líneas de fresa transgénicas con genes silenciados que codifican para enzimas pectinolíticas

Se han evaluado algunos indicadores de calidad del fruto en líneas transgénicas de fresa con los genes de poligalacturonasa FaPG1 (líneas PG) o pectato liasa FaplC (líneas APEL) silenciados. Se analizaron dos líneas independientes por genotipo transgénico. No se observaron diferencias en el contenido de sólidos solubles entre las líneas transgénicas y el control. De igual forma, la acidez total y el pH fueron similares en las líneas PG29, APEL21 y el control; sin embargo, la acidez de los frutos de las líneas PG62 y APEL39 fue superior al control. Los parámetros de color L*, a* y b* fueron similares en todos los genotipos; sin embargo, el contenido en antocianos fue menor en la línea APEL21. Los valores más altos de firmeza de fruto, estimada mediante un ensayo de extrusión, se observaron en las dos líneas transgénicas PG y en la línea APEL39. En cuanto a las pérdidas por goteo (drip loss), la línea APEL39 presentó un valor mayor que el control, pero la línea APEL21 registró valores menores. El contenido de compuestos fenólicos se analizó en la línea PG29, no encontrándose diferencias estadísticas con respecto al control. Finalmente, la capacidad del fruto para captar radicales libres fue ligeramente menor en la línea PG29 que en el control. Los resultados indican que el silenciamiento de los genes de pectinasas incrementa significativamente la firmeza de la fresa sin modificar sustancialmente parámetros de calidad del fruto maduro como color, acidez, sólidos solubles o contenido en antocianos.

Induction of resistance to fall armyworm (Spodoptera frugiperda) (Lepidoptera: Noctuidae) in transgenic and conventional corn plants

The fall armyworm (Spodoptera frugiperda) is an important pest of corn in Brazil. Insecticides are applied to reduce the losses caused by this pest. Integrated control methods, including resistance induction in plants using silicon and transgenic hybrids, must be used to reduce the impacts caused by insecticide application. The aim of this study was to assess the effects of calcium silicate application (CaSi4) to the sowing furrow on S. frugiperda damage to and incidence on conventional and transgenic genotypes with different Bt technologies. The treatments were arranged in a randomized block design in a 3x4x4 factorial scheme with three corn hybrids, Morgan 30A91 PRO Power Core (Cry1F, Cry1A105, Cry2Ab2 Bt toxin), Morgan 20A55 Herculex (Cry1F Bt toxin) and AG 1051 (conventional); four silicon doses, 0, 300, 600 and 900 kg. ha-1 calcium and magnesium silicate (Agrosilicio Plus, Ca = 25%, Mg = 6%, Si = 10.5%); and four assessment times, 15, 30, 45 and 60 days after emergence (DAE). Four replicates were performed. The mean number of caterpillars per plant, damage caused by S. frugiperda, and production components were assessed. Calcium and magnesium silicate application induced resistance in corn plants, thus reducing the damage caused by S. frugiperda. Corn responded to resistance induction with increasing doses of calcium and magnesium silicate. The transgenic hybrid with three proteins (Morgan 30A91 PRO) improved protection against S. frugiperda. The interaction between silicate fertilization and transgenics produced a synergistic effect, suggesting a viable alternative for S. frugiperda control.

A vector concept for the systematic creation and unambiguous identification of transgenic genotypes

A vector concept for the systematic creation and unambiguous identification of transgenic genotypes