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1.
Metin Konus Cornelia Koy Stefan Mikkat Michael Kreutzer Ralf Zimmermann Mesude Iscan Michael O. Glocker 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2013,8(2):152-162
Helicoverpa armigera is an insect that causes important economic losses in crops. To reduce this loss, pyrethroids have been commonly used against H. armigera in farming areas. However, excess and continuous usage of pyrethroids cause resistance in H. armigera. Therefore, expressions of midgut proteins of two H. armigera field populations were compared to those of a susceptible strain by 2-D PAGE and MALDI-ToF-MS. Our results indicate that H. armigera reacts to pyrethroid-induced stress mainly by increasing the expression of energy metabolism-related proteins, such as ATP synthase and arginine kinase. NADPH cytochrome P450 reductase, also up-regulated, could play a role in detoxification of toxic pyrethroid metabolites, such as 3-phenoxybenzaldehyde. Interestingly, while GSTs were not found up-regulated in the comparative proteome analysis, biochemical assays showed significant increases of enzyme activities in both field populations as compared to the susceptible strain. Similarly, although esterases were not found differentially expressed, biochemical assays showed significant increases of esterase activities in both field populations. Thus, esterases are also proposed to be involved in metabolic responses towards pyrethroid insecticide-induced stress. In conclusion, we suggest increased energy metabolism in the midgut tissue of H. armigera as a general prerequisite for compensating the costs of energy-consuming detoxification processes. 相似文献
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The cotton bollworm Helicoverpa armigera and the tobacco budworm Heliothis virescens are closely related generalist insect herbivores and serious pest species on a number of economically important crop plants including cotton. Even though cotton is well defended by its major defensive compound gossypol, a toxic sesquiterpene dimer, larvae of both species are capable of developing on cotton plants. In spite of severe damage larvae cause on cotton plants, little is known about gossypol detoxification mechanisms in cotton-feeding insects. Here, we detected three monoglycosylated and up to five diglycosylated gossypol isomers in the feces of H. armigera and H. virescens larvae fed on gossypol-supplemented diet. Candidate UDP-glycosyltransferase (UGT) genes of H. armigera were selected by microarray studies and in silico analyses and were functionally expressed in insect cells. In enzymatic assays, we show that UGT41B3 and UGT40D1 are capable of glycosylating gossypol mainly to the diglycosylated gossypol isomer 5 that is characteristic for H. armigera and is absent in H. virescens feces. In conclusion, our results demonstrate that gossypol is partially metabolized by UGTs via glycosylation, which might be a crucial step in gossypol detoxification in generalist herbivores utilizing cotton as host plant. 相似文献
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Mark G. Teese Peter M. Campbell Colin Scott Karl H.J. Gordon Adam Southon Daniel Hovan Charles Robin Robyn J. Russell John G. Oakeshott 《Insect biochemistry and molecular biology》2010,40(1):1-16
Some of the resistance of Helicoverpa armigera to conventional insecticides such as organophosphates and synthetic pyrethroids appears to be due to metabolic detoxification by carboxylesterases. To investigate the H. armigera carboxyl/cholinesterases, we created a data set of 39 putative paralogous H. armigera carboxyl/cholinesterase sequences from cDNA libraries and other sources. Phylogenetic analysis revealed a close relationship between these sequences and 70 carboxyl/cholinesterases from the recently sequenced genome of the silkworm, Bombyx mori, including several conserved clades of non-catalytic proteins. A juvenile hormone esterase candidate from H. armigera was identified, and B. mori orthologues were proposed for 31% of the sequences examined, however low similarity was found between lepidopteran sequences and esterases previously associated with insecticide resistance from other insect orders. A proteomic analysis of larval esterases then enabled us to match seven of the H. armigera carboxyl/cholinesterase sequences to specific esterase isozymes. All identified sequences were predicted to encode catalytically active carboxylesterases, including six proteins with N-terminal signal peptides and N-glycans, with two also containing C-terminal signals for glycosylphosphatidylinositol anchor attachment. Five of these sequences were matched to zones of activity on native PAGE at relative mobility values previously associated with insecticide resistance in this species. 相似文献
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Gossypol is a polyphenolic secondary metabolite produced by cotton plants, which is toxic to many organisms. Gossypol's aldehyde groups are especially reactive, forming Schiff bases with amino acids of proteins and cross-linking them, inhibiting enzyme activities and contributing to toxicity. Very little is known about gossypol's mode of action and its detoxification in cotton-feeding insects that can tolerate certain concentrations of this compound. Here, we tested the toxicity of gossypol and a gossypol derivative lacking free aldehyde groups (SB-gossypol) toward Helicoverpa armigera and Heliothis virescens, two important pests on cotton plants. Larval feeding studies with these two species on artificial diet supplemented with gossypol or SB-gossypol revealed no detectable toxicity of gossypol, when the aldehyde groups were absent. A cytochrome P450 enzyme, CYP6AE14, is upregulated in H. armigera feeding on gossypol, and has been claimed to directly detoxify gossypol. However, using in vitro assays with heterologously expressed CYP6AE14, no metabolites of gossypol were detected, and further studies suggest that gossypol is not a direct substrate of CYP6AE14. Furthermore, larvae feeding on many other plant toxins also upregulate CYP6AE14. Our data demonstrate that the aldehyde groups are critical for the toxicity of gossypol when ingested by H. armigera and H. virescens larvae, and suggest that CYP6AE14 is not directly involved in gossypol metabolism, but may play a role in the general stress response of H. armigera larvae toward plant toxins. 相似文献
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Molecular cloning and recombinant expression of cytochrome P450 CYP6B6 from Helicoverpa armigera in Escherichia coli 总被引:1,自引:0,他引:1
The cytochrome P450 s play a significant role in the detoxification of plant allelochemicals and synthetic insecticides in Lepidoptera. In the cotton bollworm Helicoverpa armigera, 2-tridecanone and quercetin can induce P450-dependent monooxygenase activity increased, to further the characterization of P450, the CYP6B6 of cotton bollworm (H. armigera) was cloned, sequenced and expressed in pMAL-p2x vector and expressed in Escherichia coli. The deduced amino acid sequences of cytochrome P450 in the midgut and fat body of H. armigera showed 98.23 and 97.84 % similarity with CYP6B6, respectively. According to nomenclature of P450 s, the P450 genes we got belong to CYP6B. Purification of recombinant protein based on the affinity of MBP for maltose was achieved by Mal-Tag magnetic beads. The purified protein was used to raise polyclonal antibody according to classical procedure. SDS–PAGE and Western blot results indicated that MBP-CYP6B6 had been successfully expressed. The ethoxycoumarin-O-deethylase activity of the purified recombinant protein was 36.5 ± 8.12 pmol of 7-hydroxycoumarin/min/mg protein, which showed the fusion MBP-CYP6B6 had the ability to o-deethylase of 7-ethoxycoumarin. 相似文献
7.
M. D. Dearing 《Oecologia》1996,109(1):122-131
I investigated the effects of tannin consumption, using plant tannins naturally occurring in the diet, on a herbivorous mammal,
the North American pika, Ochotona princeps. The objectives were to determine if a high-tannin diet influenced protein and dry matter apparent digestibility, fiber digestibility
and production of detoxification by-products. Additionally, I examined the possibility that pikas produce salivary tannin-binding
proteins, a potential mechanism for avoiding detrimental effects of tannins. My results demonstrate that although pikas constitutively
produce salivary tannin-binding proteins, animals consuming a high-tannin diet of Acomastylis rossii exhibited lower dry matter, protein and fiber digestion and excreted higher concentrations of detoxification by-products.
Thus, A. rossii tannins are potential toxins as well as digestibility reducers. I propose a hypothesis coupling detoxification to reduced
fiber digestion that is applicable to pikas as well as other mammalian herbivores consuming phenolic-rich diets.
Received: 31 July 1995 / Accepted: 9 July 1996 相似文献
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Vishal V. Dawkar Yojana R. Chikate Tushar H. More Vidya S. Gupta Ashok P. Giri 《Insect Science》2016,23(1):68-77
Helicoverpa armigera is a key pest in many vital crops, which is mainly controlled by chemical strategies. To manage this pest is becoming challenging due to its ability and evolution of resistance against insecticides. Further, its subsequent spread on nonhost plant is remarkable in recent times. Hence, decoding resistance mechanism against phytochemicals and synthetic insecticides is a major challenge. The present work describes that the digestion, defense and immunity related enzymes are associated with chlorpyrifos resistance in H. armigera. Proteomic analysis of H. armigera gut tissue upon feeding on chlorpyrifos containing diet (CH) and artificial diet (AD) using nano‐liquid chromatography–mass spectrometry identified upregulated 23‐proteins in CH fed larvae. Database searches combined with gene ontology analysis revealed that the identified gut proteins engrossed in digestion, proteins crucial for immunity, adaptive responses to stress, and detoxification. Biochemical and quantitative real‐time polymerase chain reaction analysis of candidate proteins indicated that insects were struggling to get nutrients and energy in presence of CH, while at the same time endeavoring to metabolize chlorpyrifos. Moreover, we proposed a potential processing pathway of chlorpyrifos in H. armigera gut by examining the metabolites using gas chromatography–mass spectrometry. H. armigera exhibit a range of intriguing behavioral, morphological adaptations and resistance to insecticides by regulating expression of proteins involved in digestion and detoxification mechanisms to cope up with chlorpyrifos. In these contexts, as gut is a rich repository of biological information; profound analysis of gut tissues can give clues of detoxification and resistance mechanism in insects. 相似文献
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Hemlata M. Kotkar 《Journal of insect physiology》2009,55(8):663-1780
Midgut digestive amylases and proteinases of Helicoverpa armigera, a polyphagous and devastating insect pest of economic importance have been studied. We also identified the potential of a sorghum amylase inhibitor against H. armigera midgut amylase. Amylase activities were detected in all the larval instars, pupae, moths and eggs; early instars had lower amylase levels which steadily increased up to the sixth larval instar. Qualitative and quantitative differences in midgut amylases of H. armigera upon feeding on natural and artificial diets were evident. Natural diets were categorized as one or more members of legumes, vegetables, flowers and cereals belonging to different plant families. Amylase activity and isoform patterns varied depending on host plant and/or artificial diet. Artificial diet-fed H. armigera larvae had comparatively high amylase activity and several unique amylase isoforms. Correlation of amylase and proteinase activities of H. armigera with the protein and carbohydrate content of various diets suggested that H. armigera regulates the levels of these digestive enzymes in response to macromolecular composition of the diet. These adjustments in the digestive enzymes of H. armigera may be to obtain better nourishment from the diet and avoid toxicity due to nutritional imbalance. H. armigera, a generalist feeder experiences a great degree of nutritional heterogeneity in its diet. An investigation of the differences in enzyme levels in response to macronutrient balance and imbalance highlight their importance in insect nutrition. 相似文献
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- 1 The allocation of defensive compounds of transgenic Bt (cv. GK‐12) and nontransgenic cotton (cv. Simian‐3) grown in elevated CO2 in response to infestation by cotton bollworm Helicoverpa armigera (Hübner) was studied in closed‐dynamics CO2 chambers.
- 2 A significant reduction in foliar nitrogen content and Bt toxin protein occurred when transgenic Bt cotton grew under elevated CO2. A significantly higher carbon/nitrogen ratio as well as condensed tannin and gossypol contents was observed for transgenic Bt (cv. GK‐12) and nontransgenic cotton in elevated CO2, in partial support of the carbon nutrient balance hypothesis as a result of limiting nitrogen and excess carbon in cotton plants in response to elevated CO2.
- 3 The CO2 level and infestation time significantly affected the foliar nitrogen, condensed tannin, gossypol and Bt toxin protein contents of cotton plants after feeding by H. armigera. The interaction between CO2 levels × cotton variety had a significant effect on foliar nitrogen content after injury by H. armigera.
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Effects of elevated CO2 and transgenic Bt cotton on plant chemistry, performance, and feeding of an insect herbivore, the cotton bollworm 总被引:1,自引:0,他引:1
Fajun Chen Gang Wu Feng Ge Megha N. Parajulee & Ram B. Shrestha 《Entomologia Experimentalis et Applicata》2005,115(2):341-350
Effects of elevated atmospheric CO2 (double‐ambient CO2) on the growth and metabolism of cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), fed on transgenic Bacillus thuringiensis (Berliner) (Bt) cotton [Cry1A(c)], grown in open‐top chambers, were studied. Two levels of CO2 (ambient and double‐ambient) and two cotton cultivars (non‐transgenic Simian‐3 and transgenic GK‐12) were deployed in a completely randomized design with four treatment combinations, and the cotton bollworm was reared on each treatment simultaneously. Plants of both cotton cultivars had lower nitrogen and higher total non‐structural carbohydrates (TNC), TNC:Nitrogen ratio, condensed tannin, and gossypol under elevated CO2. Elevated CO2 further resulted in a significant decrease in Bt toxin level in GK‐12. The changes in chemical components in the host plants due to increased CO2 significantly affected the growth parameters of H. armigera. Both transgenic Bt cotton and elevated CO2 resulted in a reduced body mass, lower fecundity, decreased relative growth rate (RGR), and decreased mean relative growth rate in the bollworms. Larval life‐span was significantly longer for H. armigera fed transgenic Bt cotton. Significantly reduced larval, pupal, and adult moth weights were observed in the bollworms fed elevated CO2‐grown transgenic Bt cotton compared with those of bollworms reared on non‐transgenic cotton, regardless of the CO2 level. The efficiency of conversion of ingested food and of digested food of the bollworm were significantly reduced when fed transgenic Bt cotton, but there was no significant CO2 or CO2× cotton cultivar interaction. Approximate digestibility of larvae reared on transgenic cotton grown in elevated CO2 was higher compared to that of larvae fed non‐transgenic cotton grown at ambient CO2. The damage inflicted by cotton bollworm on cotton, regardless of the presence or absence of insecticidal genes, is predicted to be more serious under elevated CO2 conditions because of individual compensatory feeding on host plants caused by nitrogen deficiency. 相似文献
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The relatively low susceptibility ofHelicoverpa armigera to CrylAc, its history of resistance to chemical insecticides and the seasonal decline in expression of CrylAc in transgenic cotton necessitated the development of cotton expressing two insecticidal proteins to provide sustainable control of this multinational pest. To manage the resistance issue, it was essential that the second insecticidal protein have a significantly different mode of action to CrylAc. A common feature of resistance to CrylA proteins in several species as well as H. armigera has been a change in the binding site. A study of binding sites for some Cry proteins in the brush border membrane vesicles (BBMV) ofH. armigera and Helicoverpa punctigera was undertaken. The binding affinity for CrylAc was higher than for CrylAb, matching their relative toxicities, and CrylAc and CrylAb were found to share at least one binding site in both I-1. armigera and I-1. punctigera. However Cry2Aa did not compete with CrylAc for binding and so could be used in transgenic cotton in combination with CrylAc to control H. armigera and manage resistance. Variation in the susceptibilities of three different H. armigera strains to CrylAc correlated with the parameter Bmax/Kcom. 相似文献
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The interactions between plants and insects play an important role in ecosystems. Climate change and cropping patterns can affect herbivorous pest insect dynamics. Understanding the reasons for population fluctuations can help improve integrated pest management strategies. Here, a 25‐year dataset on climate, cropping planting structure, and the population dynamics of cotton bollworms (Helicoverpa armigera) from Bachu County, south Xinjiang, China, was analyzed to assess the effects of changes in climate and crop planting structure on the population dynamics of H. armigera. The three generations of H. armigera showed increasing trends in population size with climate warming, especially in the third generation. The relative abundances of the first and second generations decreased, but that of the third generation increased. Rising temperature and precipitation produced different impacts on the development of different generations. The population numbers of H. armigera increased with the increase in the non‐Bacillus thuringiensis (Bt) cotton‐planted area. Asynchrony of abrupt changes existed among climate change, crop flowering dates, and the phenology of H. armigera moths. The asynchronous responses in crop flowering dates and phenology of H. armigera to climate warming would expand in the future. The primary factors affecting the first, second, and third generations of moths were Tmean in June, the last appearance date of the second generation of moths, and the duration of the third generation of moths, respectively. To reduce the harm to crops caused by H. armigera, Bt cotton should be widely planted. 相似文献
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New Resistance Mechanism in Helicoverpa armigera Threatens Transgenic Crops Expressing Bacillus thuringiensis Cry1Ac Toxin 总被引:1,自引:0,他引:1
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Robin V. Gunning Ho T. Dang Fred C. Kemp Ian C. Nicholson Graham D. Moores 《Applied microbiology》2005,71(5):2558-2563
In Australia, the cotton bollworm, Helicoverpa armigera, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the Bacillus thuringiensis toxin Cry1Ac) has been grown for H. armigera control since 1996. It is demonstrated here that a population of Australian H. armigera has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant H. armigera larvae were able to survive on Cry1Ac transgenic cotton (Ingard) The resistance phenotype is inherited as an autosomal semidominant trait. Resistance was associated with elevated esterase levels, which cosegregated with resistance. In vitro studies employing surface plasmon resonance technology and other biochemical techniques demonstrated that resistant strain esterase could bind to Cry1Ac protoxin and activated toxin. In vivo studies showed that Cry1Ac-resistant larvae fed Cy1Ac transgenic cotton or Cry1Ac-treated artificial diet had lower esterase activity than non-Cry1Ac-fed larvae. A resistance mechanism in which esterase sequesters Cry1Ac is proposed. 相似文献
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King Solomon Ebenezer Ramesh Nachimuthu Prabha Thiagarajan Rajesh Kannan Velu 《Bioinformation》2013,9(15):792-795
Any novel protein introduced into the GM crops need to be evaluated for cross affinity on living organisms. Many researchers are
currently focusing on the impact of Bacillus thuringiensis cotton on soil and microbial diversity by field experiments. In spite of this,
in silico approach might be helpful to elucidate the impact of cry genes. The crystal a protein which was produced by Bt at the time
of sporulation has been used as a biological pesticide to target the insectivorous pests like Cry1Ac for Helicoverpa armigera and
Cry2Ab for Spodoptera sp. and Heliothis sp. Here, we present the comprehensive in silico analysis of Cry1Ac and Cry2Ab proteins
with available in silico tools, databases and docking servers. Molecular docking of Cry1Ac with procarboxypeptidase from
Helicoverpa armigera and Cry1Ac with Leucine aminopeptidase from Bos taurus has showed the 125th amino acid position to be the
preference site of Cry1Ac protein. The structures were compared with each other and it showed 5% of similarity. The cross affinity
of this toxin that have confirmed the earlier reports of ill effects of Bt cotton consumed by cattle. 相似文献