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1.
Sci Rep ; 11(1): 12428, 2021 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-34127751

RESUMO

Sugarcane (Saccharum officinarum L.) is a cash crop grown commercially for its higher amounts of sucrose, stored within the mature internodes of the stem. Numerous studies have been done for the resistance development against biotic and abiotic stresses to save the sucrose yields. Quality and yield of sugarcane production is always threatened by the damages of cane borers and weeds. In current study two problems were better addressed through the genetic modification of sugarcane for provision of resistance against insects and weedicide via the expression of two modified cane borer resistant CEMB-Cry1Ac (1.8 kb), CEMB-Cry2A (1.9 kb) and one glyphosate tolerant CEMB-GTGene (1.4 kb) genes, driven by maize Ubiquitin Promoter and nos terminator. Insect Bio-toxicity assays were carried out for the assessment of Cry proteins through mortality percent of shoot borer Chilo infuscatellus at 2nd instar larvae stage. During V0, V1 and V2 generations young leaves from the transgenic sugarcane plants were collected at plant age of 20, 40, 60, 80 days and fed to the Chilo infuscatellus larvae. Up to 100% mortality of Chilo infuscatellus from 80 days old transgenic plants of V2 generation indicated that these transgenic plants were highly resistant against shoot borer and the gene expression level is sufficient to provide complete resistance against target pests. Glyphosate spray assay was carried out for complete removal of weeds. In V1-generation, 70-76% transgenic sugarcane plants were found tolerant against glyphosate spray (3000 mL/ha) under field conditions. While in V2-generation, the replicates of five selected lines 4L/2, 5L/5, 6L/5, L8/4, and L9/6 were found 100% tolerant against 3000 mL/ha glyphosate spray. It is evident from current study that CEMB-GTGene, CEMB-Cry1Ac and CEMB-Cry2A genes expression in sugarcane variety CPF-246 showed an efficient resistance against cane borers (Chilo infuscatellus) and was also highly tolerant against glyphosate spray. The selected transgenic sugarcane lines showed sustainable resistance against cane borer and glyphosate spray can be further exploited at farmer's field level after fulfilling the biosafety requirements to boost the sugarcane production in the country.


Assuntos
Produtos Agrícolas/genética , Resistência à Doença/genética , Controle de Pragas/métodos , Plantas Geneticamente Modificadas/genética , Saccharum/genética , Animais , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/parasitologia , Glicina/análogos & derivados , Glicina/farmacologia , Resistência a Herbicidas/genética , Larva , Mariposas , Proteínas de Plantas/genética , Plantas Daninhas , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/parasitologia , Saccharum/efeitos dos fármacos , Saccharum/parasitologia
2.
Nat Commun ; 12(1): 3380, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099714

RESUMO

Plant-parasitic nematodes (PPNs) are economically important pests of agricultural crops, and soybean cyst nematode (SCN) in particular is responsible for a large amount of damage to soybean. The need for new solutions for controlling SCN is becoming increasingly urgent, due to the slow decline in effectiveness of the widely used native soybean resistance derived from genetic line PI 88788. Thus, developing transgenic traits for controlling SCN is of great interest. Here, we report a Bacillus thuringiensis delta-endotoxin, Cry14Ab, that controls SCN in transgenic soybean. Experiments in C. elegans suggest the mechanism by which the protein controls nematodes involves damaging the intestine, similar to the mechanism of Cry proteins used to control insects. Plants expressing Cry14Ab show a significant reduction in cyst numbers compared to control plants 30 days after infestation. Field trials also show a reduction in SCN egg counts compared with control plants, demonstrating that this protein has excellent potential to control PPNs in soybean.


Assuntos
Toxinas de Bacillus thuringiensis/genética , Produtos Agrícolas/parasitologia , Resistência à Doença/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Soja/parasitologia , Tylenchoidea/patogenicidade , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis/metabolismo , Bioensaio , Caenorhabditis elegans , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Endotoxinas/metabolismo , Feminino , Engenharia Genética , Proteínas Hemolisinas/metabolismo , Melhoramento Vegetal/métodos , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/parasitologia , Soja/genética , Soja/metabolismo , Tylenchoidea/isolamento & purificação
3.
PLoS One ; 16(5): e0251134, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33945577

RESUMO

The efficacy and non-target arthropod effects of transgenic DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 Bt cotton, expressing proteins Cry1Ac, Cry1F and Vip3Aa19, was examined through field trials in Brazil. Fifteen field efficacy experiments were conducted from 2014 through the 2020 growing season across six different states in Brazil to evaluate performance against key lepidopteran pests through artificial infestations of Chrysodeixis includens (Walker), Spodoptera frugiperda (J.E. Smith,1797), Spodoptera cosmioides (Walker, 1858) and Chloridea virescens (F., 1781), and natural infestations of Alabama argillacea (Hübner) and S. frugiperda. The impact of this Bt cotton technology on the non-target arthropod community in Brazilian cotton production systems was also assessed in a multi-site experiment. DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton significantly reduced the feeding damage caused by S. frugiperda, S. cosmioides, C. includens, C. virescens and A. argillacea, causing high levels of mortality (greater than 99%) to all target lepidopteran pests evaluated during vegetative and/or reproductive stages of crop development. Non-target arthropod community-level analyses confirmed no unintended effects on the arthropod groups monitored. These results demonstrate the value of transgenic Bt cotton containing event DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 for consideration as part of an integrated approach for managing key lepidopteran pests in Brazilian cotton production systems.


Assuntos
Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-dissulfônico/análogos & derivados , Artrópodes/crescimento & desenvolvimento , Gossypium/metabolismo , Gossypium/parasitologia , Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-dissulfônico/metabolismo , Animais , Brasil , Controle de Insetos , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Controle Biológico de Vetores/métodos , Folhas de Planta/parasitologia , Plantas Geneticamente Modificadas/parasitologia , Spodoptera/crescimento & desenvolvimento
4.
PLoS One ; 16(4): e0249699, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33831084

RESUMO

Plants have developed various mechanisms to respond specifically to each biotrophic attack. It has been shown that the electrical signals emitted by plants are associated with herbivory stress responses and can lead to the activation of multiple defences. Bt cotton is a genetically modified pest-resistant plant that produces an insecticide from Bacillus thuringiensis (Bt) to control Lepidopteran species. Surprisingly, there is no study-yet, that characterizes the signalling mechanisms in transgenic cotton plants attacked by non-target insects, such as aphids. In this study, we characterized the production of electrical signals on Bt and non-Bt cotton plants infested with Aphis gossypii and, in addition, we characterized the dispersal behaviour of aphids to correlate this behaviour to plant signalling responses. Electrical signalling of the plants was recorded with an extracellular measurement technique. Impressively, our results showed that both Bt and non-Bt cotton varieties, when attacked by A. gossypii, emitted potential variation-type electrical signals and clearly showed the presence of distinct responses regarding their perception and the behaviour of aphids, with evidence of delay, in terms of signal amount, and almost twice the amount of Cry1F protein was observed on Bt cotton plants at the highest density of insects/plant. We present in our article some hypotheses that are based on plant physiology and insect behaviour to explain the responses found on Bt cotton plants under aphid stress.


Assuntos
Afídeos/microbiologia , Bacillus thuringiensis/metabolismo , Gossypium/microbiologia , Gossypium/parasitologia , Estresse Fisiológico/fisiologia , Animais , Gossypium/genética , Herbivoria/fisiologia , Insetos/microbiologia , Inseticidas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/microbiologia , Plantas Geneticamente Modificadas/parasitologia , Transdução de Sinais/genética , Estresse Fisiológico/genética
5.
Int J Mol Sci ; 22(4)2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33578757

RESUMO

We present a reproducible procedure for transforming somatic embryos of cork oak with the CsTL1 gene that codes for a thaumatin-like protein, in order to confer tolerance to Phytophthora cinnamomi. Different concentrations/combinations of the antibiotics carbenicillin and cefotaxime, as bacteriostatic agents, and kanamycin, as a selective agent, were tested. A lethal dose of 125 mg/L kanamycin was employed to select transgenic somatic embryos, and carbenicillin was used as a bacteriostatic agent at a concentration of 300 mg/L, which does not inhibit somatic embryo proliferation. The transformation efficiency was clearly genotype-dependent and was higher for the TGR3 genotype (17%) than for ALM80 (4.5%) and ALM6 (2%). Insertion of the transgenes in genomic DNA was confirmed by PCR analysis, whereas expression of the CsTL1 gene was evaluated by semi-quantitative real-time PCR (qPCR) analysis. A vitrification treatment successfully cryopreserved the transgenic lines generated. The antifungal activity of the thaumatin-like protein expressed by the gene CsTL1 was evaluated in an in vitro bioassay with the oomycete P. cinnamomi. Of the eight transgenic lines analyzed, seven survived for between one or two times longer than non-transgenic plantlets. Expression of the CsTL1 gene and plantlet survival days were correlated, and survival was generally greater in plantlets that strongly expressed the CsTL1 gene.


Assuntos
Doenças das Plantas/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/embriologia , Quercus/embriologia , Agrobacterium tumefaciens/genética , Resistência à Doença , Phytophthora/fisiologia , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Quercus/genética , Quercus/parasitologia , Transformação Genética , Transgenes
6.
Sci Rep ; 11(1): 2050, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479482

RESUMO

Genetic engineering (GM) has great potential to improve maize productivity, but rises some concerns on unintended effects, and equivalent as their comparators. There are some limitations through targeted analysis to detect the UE in genetically modified organisms in many previous studies. We here reported a case-study on the effects of introducing herbicides and insect resistance (HIR) gene cassette on molecular profiling (transcripts and metabolites) in a popular maize variety Zhengdan958 (ZD958) in China. We found that introducing HIR gene cassette bring a limited numbers of differential abundant genes (DAGs) or differential abundant metabolites (DAMs) between transgenic events and non-transgenic control. In contrast, averaged 10 times more DAGs and DAMs were observed when performed comparison under different growing environments in three different ecological regions of China than the numbers induced by gene effects. Major biological pathways relating to stress response or signaling transduction could explain somehow the effects of growing environments. We further compared two transgenic events mediated ZD958 (GM-ZD958) with either transgenic parent GM-Z58, and other genetic background nonGM-Z58, nonGM-ZD958, and Chang7-2. We found that the numbers of DAGs and DAMs between GM-ZD958 and its one parent maize variety, Z58 or GM-Z58 is equivalent, but not Chang7-2. These findings suggest that greater effects due to different genetic background on altered molecular profiling than gene modification itself. This study provides a case evidence indicating marginal effects of gene pleiotropic effects, and environmental effects should be emphasized.


Assuntos
Resistência a Herbicidas/genética , Plantas Geneticamente Modificadas/genética , Transcriptoma/genética , Zea mays/genética , Animais , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas/genética , Engenharia Genética , Herbicidas/efeitos adversos , Insetos/genética , Insetos/patogenicidade , Metabolômica , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/parasitologia , Zea mays/crescimento & desenvolvimento , Zea mays/parasitologia
7.
PLoS One ; 16(1): e0239958, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33428626

RESUMO

Insect pests cause serious damage in crop production, and various attempts have been made to produce insect-resistant crops, including the expression of genes for proteins with anti-herbivory activity, such as Bt (Bacillus thuringiensis) toxins. However, the number of available genes with sufficient anti-herbivory activity is limited. MLX56 is an anti-herbivory protein isolated from the latex of mulberry plants, and has been shown to have strong growth-suppressing activity against the larvae of a variety of lepidopteran species. As a model of herbivore-resistant plants, we produced transgenic tomato lines expressing the gene for MLX56. The transgenic tomato lines showed strong anti-herbivory activities against the larvae of the common cutworm, Spodoptera litura. Surprisingly, the transgenic tomato lines also exhibited strong activity against the attack of western flower thrips, Frankliniera occidentalis. Further, growth of the hadda beetle, Henosepilachna vigintioctopunctata, fed on leaves of transgenic tomato was significantly retarded. The levels of damage caused by both western flower thrips and hadda beetles were negligible in the high-MLX56-expressing tomato line. These results indicate that introduction of the gene for MLX56 into crops can enhance crop resistance against a wide range of pest insects, and that MLX56 can be utilized in developing genetically modified (GM) pest-resistant crops.


Assuntos
Expressão Gênica , Látex , Lycopersicon esculentum , Morus/genética , Proteínas de Plantas , Plantas Geneticamente Modificadas , Animais , Bacillus thuringiensis , Insetos , Lycopersicon esculentum/genética , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/parasitologia , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/parasitologia
8.
Trends Biotechnol ; 39(2): 105-107, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32713608

RESUMO

In late 2018, the highly destructive and polyphagous fall armyworm was first detected in China. It is now a major economic threat to corn production. In this article, the main control strategies that are available are reviewed and prospects to manage this pest with Bacillus thuringiensis (Bt) corn in China are discussed.


Assuntos
Controle de Pragas , Plantas Geneticamente Modificadas , Spodoptera , Animais , Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Biotecnologia , China , Endotoxinas/genética , Proteínas Hemolisinas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Spodoptera/fisiologia , Zea mays/genética , Zea mays/parasitologia
9.
PLoS One ; 15(11): e0242791, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33253273

RESUMO

The Western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte is one of the most economically important insect pests in North America. Since 2003, transgenic maize expressing WCR-active proteins from Bacillus thuringiensis (Bt) have been widely adopted as the main approach to controlling WCR in the U.S. However, the emergence of field resistance to the Bt proteins in current commercial products has been documented in recent years, highlighting the need to develop additional tools for controlling this devasting pest. Here we report the discovery of Vpb4Da2 (initially assigned as Vip4Da2), a new insecticidal protein highly selective against WCR, through high-throughput genome sequencing of a Bt strain sourced from grain dust samples collected in the eastern and central regions of the US. Vpb4Da2 contains a sequence and domain signature distinct from families of other WCR-active proteins. Under field conditions, transgenic maize expressing Vpb4Da2 demonstrates commercial-level (at or below NIS 0.25) root protection against WCR, and reduces WCR beetle emergence by ≥ 97%. Our studies also conclude that Vpb4Da2 controls WCR populations that are resistant to WCR-active transgenic maize expressing Cry3Bb1, Cry34Ab1/Cry35Ab1 (reassigned as Gpp34Ab1/Tpp35Ab1), or DvSnf7 RNA. Based on these findings, Vpb4Da2 represents a valuable new tool for protecting maize against WCR.


Assuntos
Toxinas de Bacillus thuringiensis/genética , Besouros/genética , Controle Biológico de Vetores , Zea mays/genética , Animais , Bacillus thuringiensis/genética , Besouros/patogenicidade , Proteínas Hemolisinas/genética , Humanos , Resistência a Inseticidas/genética , Inseticidas/efeitos adversos , Inseticidas/química , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Zea mays/parasitologia
10.
PLoS One ; 15(10): e0239910, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002075

RESUMO

Transgenic cotton expressing Cry51Aa2.834_16 Bt toxin (hereafter referred to as MON 88702) has the potential to be an important tool for pest management due to its unique activity against tobacco thrips, Frankliniella fusca. Unlike other Bt toxins targeting lepidopteran cotton pests, MON 88702 does not cause direct mortality but has an antixenotic effect that suppresses F. fusca oviposition. Previous work has shown neonicotinoid seed treated (NST) crops have similar behavioral effects on thrips. This study used non-choice and common garden experiments to examine how the presence of MON 88702 cotton and soybean (another F. fusca host) with and without NSTs might alter F. fusca infestation distributions. In a no-choice environment, significant larval establishment differences were observed, with untreated soybean plants becoming most heavily infested. In choice experiments, plants expressing MON 88702 or were neonicotinoid treated had significantly lower larval establishment. Larval density decreased as dispersal distance increased, suggesting reproductive decisions were negatively related to distance from the release point. Understanding how F. fusca responds to MON 88702 in an environment where adults can choose among multiple host plants will provide valuable context for projections regarding design of MON 88702 resistance refuges. Reduced larval establishment on NST cotton and soybean suggests that area-wide use of NSTs could reduce the number of susceptible F. fusca generated in unstructured crop refuges for MON 88702. These results also suggest that although the presence of NST MON 88702 could suppress reproduction and resistance selection, over time this benefit could erode resulting in increased larval establishment on NST cotton and soybean due to increased frequency of neonicotinoid resistant F. fusca populations.


Assuntos
Gossypium/parasitologia , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Doenças das Plantas/prevenção & controle , Tisanópteros/efeitos dos fármacos , Animais , Bacillus thuringiensis/genética , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Gossypium/genética , Oviposição/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Sementes/parasitologia , Soja/genética , Soja/parasitologia , Tisanópteros/patogenicidade , Tisanópteros/fisiologia
11.
Sci Rep ; 10(1): 16423, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009432

RESUMO

The potential risks of Bt rice on non-target arthropods (NTAs) should be evaluated and defined before commercial production. Recently, effects of Bt rice on NTAs under abiotic and biotic stress conditions attracted much attention. Here we reported the effects of Bt rice T1C-19 (Cry1C rice) on the non-target herbivore, Nilaparvata lugens (rice brown planthopper, BPH) with or without RDV (rice dwarf virus) infection conditions. BPH showed no feeding and oviposition preference between Bt rice T1C-19 and its non-Bt parental rice Minghui 63 (MH63), as well as between RDV-infected and RDV-free rice plants. Meanwhile, rice type, RDV infection status, and their interaction had little impacts on the survival, development and fecundity of BPH. By comparison with non-Bt control, Bt rice T1C-19 with or without RDV infection had no significant effects on the life-table parameters of BPH including rm, R0, T, DT and λ. Thus, it could be concluded that Bt rice T1C-19 doesn't affect the ecological fitness of BPH either under RDV stress or not.


Assuntos
Oryza/parasitologia , Oryza/virologia , Animais , Feminino , Fertilidade/fisiologia , Hemípteros/patogenicidade , Herbivoria/fisiologia , Masculino , Ninfa/patogenicidade , Oviposição/fisiologia , Plantas Geneticamente Modificadas/parasitologia , Plantas Geneticamente Modificadas/virologia , Reoviridae/patogenicidade
12.
J Biosci ; 452020.
Artigo em Inglês | MEDLINE | ID: mdl-33051408

RESUMO

Phytophagous insect incidence is a serious threat for reduction of crop productivity globally. There is an estimation of one fourth of crop is being destroyed by insects annually. Indeed, the development of insect-resistant crops is a great milestone in agriculture to increase crop yield and reduce pesticide dependency. Genetic engineering facilitates development of insect resistant crops by expressing bacterial δ-endotoxins and vegetative insecticidal proteins and other plant genes like lectins, protease inhibitors, etc. In addition, RNA interference and genome editing through CRISPR Cas9 also provides new solutions for the development of insect-resistant crops. The resultant genetically modified crops showed resistance against lepidopteran, dipteran, homopteran and coleopteran insects. The insect-resistant crops have made a significant economic impact worldwide in terms of higher yield and low pesticide usage. In this review, we focus on different strategies for developing transgenics against insect pest control by expressing different insecticidal proteins in crops.


Assuntos
Toxinas de Bacillus thuringiensis/genética , Produtos Agrícolas/genética , Engenharia Genética/tendências , Plantas Geneticamente Modificadas/genética , Animais , Bacillus thuringiensis/genética , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/parasitologia , Edição de Genes , Controle de Insetos/tendências , Insetos/patogenicidade , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/parasitologia
13.
PLoS One ; 15(9): e0238523, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32911522

RESUMO

Brazil and South Africa, countries with economies in transition, are characterized by a dual agrarian structure co-occurring, sometimes, alongside in the same region. Large-scale commercial farming produces crops for export to global markets on the one hand, and small-scale farming, on the other hand, provides for subsistence and local markets. In both systems, maize (Zea mays) is a key crop for these two countries. For the commercial system, maize is a commodity crop while for the small-scale system it is the prime staple crop. In commercial systems, farmers predominantly grow genetically modified (GM) hybrid maize. In small-scale systems, farmers rely on open pollinated varieties (OPVs) and/or landraces and are largely dependent on seed saving systems. The aim of this study was to understand the relationship between transgene expression rates, the resulting concentrations of the transgene product (Bt protein) and its bioactivity in insect pests following transgene flow from GM hybrid maize into non-genetically modified, non-GM near-isogenic maize hybrid (ISO) and OPVs. We modeled segregation patterns and measured cry1Ab transgene expression (mRNA quantification), Cry1Ab protein concentration and pest survival. Two groups of F1, F2 crosses and backcrosses with GM, ISO and OPV maize varieties from Brazil and South Africa were used. Bioassays with the larvae of two lepidopteran maize pest species, Helicoverpa armigera and Spodoptera littoralis, were carried out. Overall, the cry1Ab transgene outcrossed effectively into the genetic backgrounds tested. The cry1Ab transgene was stably expressed in both ISO and OPV genetic backgrounds. Transgene introgression led to consistent, though highly variable, concentrations of Cry1Ab toxins that were similar to those observed in GM parental maize. Most crosses, but not all, suggested the expected Mendelian segregation pattern. Transgene expression rates were significantly higher than expected from purely Mendelian segregation in the South African crosses. In South African materials, ISO and OPV crosses produced significantly lower Cry1Ab concentrations compared to the GM parental maize. The Cry1Ab toxins from crosses were bioactive and induced mortality rates of ≥92.19% in H. armigera and ≥40.63% in S. littoralis after a period of only 4 days. However, no correlations were observed between the quantitation of mRNA for cry1Ab and the corresponding Cry1Ab protein concentrations, nor between the Cry1Ab concentrations and insect mortality rates across different genetic backgrounds. We therefore suggest that while transcription of the cry1Ab transgene reliably determines the presence of Cry1Ab protein, mRNA levels do not reflect, by themselves, the end Cry1Ab protein concentrations found in the plant. Because predictably high Cry1Ab concentrations are a key prerequisite for effective insect resistance management (IRM) programs, this observation raises questions about the effectiveness of such programs in scenarios with complex crop genetic backgrounds. On the other hand, confirmed bioactivity in all crosses should be expected to impact small farmer's selection behavior, unknowingly favoring the insecticidal trait. This may lead to a fixation of the trait in the wider population, and may influence the genetic diversity of varieties maintained by small-scale farmers.


Assuntos
Proteínas de Bactérias/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/genética , Zea mays/genética , Animais , Toxinas de Bacillus thuringiensis , Produtos Agrícolas/genética , Cruzamentos Genéticos , Resistência à Doença , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/parasitologia , Spodoptera/fisiologia , Transgenes , Zea mays/parasitologia
14.
Int J Biol Macromol ; 163: 2270-2285, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32971164

RESUMO

The brown planthopper (BPH, Nilaparvata lugens) and striped stem borer (SSB, Chilo suppressalis) are two of the most devastating insect pests in rice, causing significant losses of rice yield. Plants evolve multiple defense responses in the process of coexisting with pests. According to different pest infestation, the plants selectively activate related pathways and downstream gene expression. However, there are very few reports of differences in defense signaling pathways after rice was attacked by BPH or SSB. We determined the transcriptional responses of rice infested with BPH and SSB for 3 and 6 h using Illumina sequencing. By comparing the difference in gene changes caused by BPH and SSB infestation in rice, multiple signal pathways and gene expression patterns, including phytohormones, secondary metabolites, plant-pathogen interaction, reactive oxygen species, defense response, transcription factors, protease inhibitor and chitinase were found significantly different. Our results provide a basis for further exploring the molecular mechanism of rice defense response caused by BPH and SSB infestation, which will add to further understanding the interactions between plants and insects, and could provide valuable resources that could be applied in insect-resistant crop breeding.


Assuntos
Resistência à Doença/genética , Oryza/genética , Doenças das Plantas/genética , Transcriptoma/genética , Animais , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Hemípteros/patogenicidade , Lepidópteros/patogenicidade , Oryza/parasitologia , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia
15.
Toxins (Basel) ; 12(9)2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32872277

RESUMO

Insecticidal toxins from Bacillus thuringiensis (Bt) are valuable tools for pest management worldwide, contributing to the management of human disease insect vectors and phytophagous insect pests of agriculture and forestry. Here, we report the effects of dual and triple Bt toxins expressed in transgenic cotton cultivars on the fitness and demographic performance of Helicoverpa zea (Boddie)-a noctuid pest, known as cotton bollworm and corn earworm. Life-history traits were determined for individuals of three field populations from a region where H. zea overwintering is likely. Triple-gene Bt cotton cultivars that express Cry and Vip3Aa toxins killed 100% of the larvae in all populations tested. In contrast, dual-gene Bt cotton that express Cry1Ac+Cry1F and Cry1Ac+Cry2Ab allowed population growth with the intrinsic rate of population growth (rm) 38% lower than on non-Bt cotton. The insects feeding on Bt cotton plants that express Cry1Ac+Cry2Ab, Cry1Ac+Cry1F, or Cry1Ab+Cry2Ae exhibited reduced larval weight, survival rate, and increased development time. Additionally, fitness parameters varied significantly among the insect populations, even on non-Bt cotton plants, likely because of their different genetic background and/or previous Bt toxin exposure. This is the first report of the comparative fitness of H. zea field populations on dual-gene Bt cotton after the recent reports of field resistance to certain Bt toxins. These results document the population growth rates of H. zea from an agricultural landscape with 100% Bt cotton cultivars. Our results will contribute to the development and validation of resistance management recommendations.


Assuntos
Toxinas de Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/metabolismo , Endotoxinas/metabolismo , Gossypium/parasitologia , Proteínas Hemolisinas/metabolismo , Mariposas/metabolismo , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/parasitologia , Animais , Toxinas de Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Endotoxinas/genética , Feminino , Regulação da Expressão Gênica de Plantas , Aptidão Genética , Gossypium/genética , Gossypium/metabolismo , Proteínas Hemolisinas/genética , Masculino , Mariposas/embriologia , Mariposas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Dinâmica Populacional , Fatores de Tempo
16.
Commun Biol ; 3(1): 407, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32733024

RESUMO

Tissue adhesion between plant species occurs both naturally and artificially. Parasitic plants establish intimate relationship with host plants by adhering tissues at roots or stems. Plant grafting, on the other hand, is a widely used technique in agriculture to adhere tissues of two stems. Here we found that the model Orobanchaceae parasitic plant Phtheirospermum japonicum can be grafted on to interfamily species. To understand molecular basis of tissue adhesion between distant plant species, we conducted comparative transcriptome analyses on both infection and grafting by P. japonicum on Arabidopsis. Despite different organs, we identified the shared gene expression profile, where cell proliferation- and cell wall modification-related genes are up-regulated. Among genes commonly induced in tissue adhesion between distant species, we showed a gene encoding a secreted type of ß-1,4-glucanase plays an important role for plant parasitism. Our data provide insights into the molecular commonality between parasitism and grafting in plants.


Assuntos
Arabidopsis/genética , Glicosídeo Hidrolases/genética , Orobanchaceae/genética , Plantas Geneticamente Modificadas/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/parasitologia , Regulação da Expressão Gênica de Plantas/genética , Interações Hospedeiro-Parasita/genética , Orobanchaceae/efeitos adversos , Plantas Geneticamente Modificadas/parasitologia , Simbiose/genética , Aderências Teciduais/genética , Aderências Teciduais/parasitologia , Transcriptoma/genética
17.
BMC Genet ; 21(1): 68, 2020 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-32631255

RESUMO

BACKGROUND: Antimicrobial peptides play important roles in both plant and animal defense systems. Moreover, over-expression of CaAMP1 (Capsicum annuum antimicrobial protein 1), an antimicrobial protein gene isolated from C. annuum leaves infected with Xanthomonas campestris pv. vesicatoria, confers broad-spectrum resistance to hemibiotrophic bacterial and necrotrophic fungal pathogens in Arabidopsis. Phytophthora root and stem rot (PRR), caused by the fungus Phytophthora sojae, is one of the most devastating diseases affecting soybean (Glycine max) production worldwide. RESULTS: In this study, CaAMP1 was transformed into soybean by Agrobacterium-mediated genetic transformation. Integration of the foreign gene in the genome of transgenic soybean plants and its expression at the translation level were verified by Southern and western blot analyses, respectively. CaAMP1 over-expression (CaAMP1-OX) lines inoculated with P. sojae race 1 exhibited enhanced and stable PRR tolerance through T2-T4 generations compared with the wild-type Williams 82 plants. Gene expression analyses in the transgenic plants revealed that the expression of salicylic acid-dependent, jasmonic acid-dependent, and plant disease resistance genes (R-genes) were significantly up-regulated after P. sojae inoculation. CONCLUSIONS: These results indicate that CaAMP1 over-expression can significantly enhance PRR tolerance in soybean by eliciting resistance responses mediated by multiple defense signaling pathways. This provides an alternative approach for developing soybean varieties with improved tolerance against soil-borne pathogenic PRR.


Assuntos
Capsicum/genética , Resistência à Doença/genética , Phytophthora/patogenicidade , Doenças das Plantas/parasitologia , Proteínas Citotóxicas Formadoras de Poros/genética , Soja/parasitologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Doenças das Plantas/genética , Plantas Geneticamente Modificadas/parasitologia , Soja/genética
18.
Toxins (Basel) ; 12(7)2020 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-32610662

RESUMO

Bacillus thuringiensis is the most successful microbial insecticide agent and its proteins have been studied for many years due to its toxicity against insects mainly belonging to the orders Lepidoptera, Diptera and Coleoptera, which are pests of agro-forestry and medical-veterinary interest. However, studies on the interactions between this bacterium and the insect species classified in the order Coleoptera are more limited when compared to other insect orders. To date, 45 Cry proteins, 2 Cyt proteins, 11 Vip proteins, and 2 Sip proteins have been reported with activity against coleopteran species. A number of these proteins have been successfully used in some insecticidal formulations and in the construction of transgenic crops to provide protection against main beetle pests. In this review, we provide an update on the activity of Bt toxins against coleopteran insects, as well as specific information about the structure and mode of action of coleopteran Bt proteins.


Assuntos
Toxinas de Bacillus thuringiensis/metabolismo , Bacillus thuringiensis/metabolismo , Agentes de Controle Biológico , Besouros/crescimento & desenvolvimento , Produtos Agrícolas/parasitologia , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/parasitologia , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis/genética , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Endotoxinas/genética , Proteínas Hemolisinas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo
19.
Proc Natl Acad Sci U S A ; 117(31): 18385-18392, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32690686

RESUMO

Transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) can suppress pests and reduce insecticide sprays, but their efficacy is reduced when pests evolve resistance. Although farmers plant refuges of non-Bt host plants to delay pest resistance, this tactic has not been sufficient against the western corn rootworm, Diabrotica virgifera virgifera In the United States, some populations of this devastating pest have rapidly evolved practical resistance to Cry3 toxins and Cry34/35Ab, the only Bt toxins in commercially available corn that kill rootworms. Here, we analyzed data from 2011 to 2016 on Bt corn fields producing Cry3Bb alone that were severely damaged by this pest in 25 crop-reporting districts of Illinois, Iowa, and Minnesota. The annual mean frequency of these problem fields was 29 fields (range 7 to 70) per million acres of Cry3Bb corn in 2011 to 2013, with a cost of $163 to $227 per damaged acre. The frequency of problem fields declined by 92% in 2014 to 2016 relative to 2011 to 2013 and was negatively associated with rotation of corn with soybean. The effectiveness of corn rotation for mitigating Bt resistance problems did not differ significantly between crop-reporting districts with versus without prevalent rotation-resistant rootworm populations. In some analyses, the frequency of problem fields was positively associated with planting of Cry3 corn and negatively associated with planting of Bt corn producing both a Cry3 toxin and Cry34/35Ab. The results highlight the central role of crop rotation for mitigating impacts of D. v. virgifera resistance to Bt corn.


Assuntos
Besouros/fisiologia , Produção Agrícola/métodos , Endotoxinas/farmacologia , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/imunologia , Zea mays/imunologia , Animais , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Besouros/efeitos dos fármacos , Produção Agrícola/economia , Endotoxinas/genética , Endotoxinas/metabolismo , Resistência a Inseticidas , Iowa , Controle Biológico de Vetores/economia , Doenças das Plantas/economia , Doenças das Plantas/imunologia , Doenças das Plantas/prevenção & controle , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Soja/crescimento & desenvolvimento , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/parasitologia
20.
Sci Rep ; 10(1): 8836, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483126

RESUMO

In plants, growth-defense tradeoffs are essential for optimizing plant performance and adaptation under stress conditions, such as pathogen attack. Root-knot nematodes (RKNs) cause severe economic losses in many crops worldwide, although little is known about the mechanisms that control plant growth and defense responses during nematode attack. Upon investigation of Arabidopsis thaliana infected with RKN (Meloidogyne incognita), we observed that the atypical transcription factor DP-E2F-like 1 (DEL1) repressed salicylic acid (SA) accumulation in RKN-induced galls. The DEL1-deficient Arabidopsis mutant (del1-1) exhibited excessive SA accumulation in galls and is more resistant to RKN infection. In addition, excessive lignification was observed in galls of del1-1. On the other hand, the root growth of del1-1 is reduced after RKN infection. Taken together, these findings suggest that DEL1 plays an important role in the balance between plant growth and defense responses to RKN infection by controlling SA accumulation and lignification.


Assuntos
Arabidopsis/metabolismo , Fatores de Transcrição/metabolismo , Tylenchoidea/fisiologia , Animais , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/parasitologia , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Parasita , Lignina/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/parasitologia , Tumores de Planta/genética , Tumores de Planta/parasitologia , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/parasitologia , Ácido Salicílico/metabolismo , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética
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