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Riaz Mahmood - One of the best experts on this subject based on the ideXlab platform.
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Diversity analysis and characterization of Coleoptera-, Hemiptera- and Nematode-active cry genes in native isolates of Bacillus thuringiensis
Annals of Microbiology, 2014Co-Authors: Ramasamy Asokan, Geetha G. Thimmegowda, Hanchipura Mallesh Mahadeva Swamy, Riaz MahmoodAbstract:Applications to combat non-lepidopteran insects are not as common as applications against lepidopteran insects. The aim of the present work was to isolate and identify Bacillus thuringiensis isolates from soil samples using five approaches, viz., analysis of crystal protein production by microscopy; detection of cry gene content by PCR, SDS-PAGE profiling; cloning and sequencing; phylogenetic analysis; and toxicity testing. Two hundred soil samples were used for isolation of B. thuringiensis and a total of 69 putative isolates of B. thuringiensis that produce parasporal crystalline inclusions were isolated from 5,267 Bacillus -like colonies. A bipyramidal inclusion was predominant in 32.2 % of the B. thuringiensis isolates compared to other shapes. Crystal protein profiling of B. thuringiensis isolates by SDS-PAGE analysis showed the presence of bands of 130, 73, 34, 25 and 13 kDa, among which 50–60 kDa bands were present abundantly. PCR analysis revealed the predominance of Coleopteran-active cry genes in these isolates. Variation in nucleotide sequences, crystal morphology and mass of crystal protein(s) purified from the isolates of B. thuringiensis revealed genetic and molecular diversity. Four strains containing Coleopteran-active cry genes showed higher toxicity against Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) adults when compared with B. thuringiensis subsp. morrisoni pathovar tenebrionis . These results are useful in emphasizing the distribution of cry genes and for prognostication of toxicity, and may contribute to the identification of novel candidate genes for bioengineered crop protection.
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Molecular Characterization and Genetic Diversity of Insecticidal Crystal Protein Genes in Native Bacillus thuringiensis Isolates
Current Microbiology, 2013Co-Authors: Hanchipura Mallesh Mahadeva Swamy, Riaz Mahmood, R. Asokan, S. N. NageshaAbstract:The Western Ghats of Karnataka natural ecosystem are among the most diverse and is one of the eight hottest hotspots of biological diversity in the world, that runs along the western part of India through four states including Karnataka. Bacillus thuringiensis ( Bt ) strains were isolated from soils of Western Ghats of Karnataka and characterized by molecular and analytical methods as a result of which 28 new Bt -like isolates were identified. Bt strains were isolated from soil samples using sodium acetate selection method. The morphology of crystals was studied using light and phase contrast microscopy. Isolates were further characterized for insecticidal cry gene by PCR, composition of toxins in bacterial crystals by SDS-PAGE cloning, sequencing and evaluation of toxicity was done. As a result 28 new Bt -like isolates were identified. Majority of the isolates showed the presence of a 55 kDa protein bands on SDS-PAGE while the rest showed 130, 73, 34, and 25 kDa bands. PCR analysis revealed predominance of Coleopteran-active cry genes in these isolates. The variations in the nucleotide sequences, crystal morphology, and mass of crystal protein(s) purified from the Bt isolates revealed genetic and molecular diversity. Three strains containing Coleopteran-active cry genes showed higher activity against larvae Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) than B. thuringiensis subsp. Morrisoni . Results indicated that Bt isolates could be utilized for bioinsecticide production, aiming to reduce the use of chemical insecticide which could be useful to use in integrated pest management to control agriculturally important pests for sustainable crop production.
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Expression of cry3A gene and its toxicity against Asian Gray Weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae).
Journal of Basic Microbiology, 2013Co-Authors: H. M. Mahadeva Swamy, Ramasamy Asokan, Geetha G. Thimmegowda, Riaz MahmoodAbstract:Coleopterans are the most damaging pests of many agricultural and forestry crops; there is an urgent need to develop effective biopesticides against these insects. Enhancers of Bt toxicity typify an opportunity to improve currently available commercial products into more effective control agents against diverse pests. A 1.9 kb DNA fragment, PCR amplified from native isolates of Bt using cry3A gene specific primers was cloned in expression vector pQE-80L and then used for transformation of Escherichia coli M15 cells. The sequence of the cloned crystal protein gene showed almost complete homology with a Coleopteran active Cry3A toxin gene with 117 mutations scattered in different domain regions encoding a protein of 645 amino acid residues in length, with a predicted molecular mass of 77.4 kDa. Phylogenetic analysis could be compulsive for new/novel Bacillus thuringiensis strains, allowing them to be grouped with related Cry proteins. The toxicity of Bt protein was determined against Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) LC50 152 ng cm(-2). Genes coding for Coleopteran active Cry3A proteins have been isolated and their efficient expression will provide the tools necessary to increase the efficacy of Cry-based biopesticide against economically important beetles.
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Identification of Semi-parasitic mites on Myllocerus undecimpustulatus undatus Marshall
2013Co-Authors: Geetha G. T, N. K. Krishna Kumar, Riaz MahmoodAbstract:The weevil Myllocerus undecimpustulatus undatus Marshall is one of the important insect pest on several host plants in India. Weevils were collected from laboratory reared population. Semi-parasitic mite was recorded on weevils. The abundance of mites varied among body parts of M. undecimpustulatus and the maximum numbers occurred in the femur, mouth parts, antennae, eyes and coxa region. The number and abundance of mites did not differ between male and female weevils. Most mites aggregated under the sub-elytral space, which presumably offers protection from the hot and dry environment. This study is the first to document the presence of mites on M. undecimpustulatus undatus Marshall in India and will help to direct future research on their interactions.
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Toxicity of different indigen isolates of Bacillus thuringiensis on mango weevil Myllocerus undecimpustulatus (Coleoptera: Curculionidae)
2013Co-Authors: N. K. Krishnakumar, H. M. Mahadeva Swamy, Riaz MahmoodAbstract:Division of Entomology and Nematology, Indian Institute of Horticultural Research (IIHR), Hessaraghatta lake post, Bangalore 560089, Karnataka, INDIA Division of Horticulture, Krishi Anusandhan Bhawan II, New Delhi 110 012 INDIA Division of Biotechnology, Indian Institute of Horticultural Research (IIHR), Hessaraghatta lake post, Bangalore 560089, Karnataka, INDIA Post-Graduate Department of Studies and Research in Biotechnology and Bioinformatics, Kuvempu University, Jnanasahayadri, Shankaraghatta, Shimoga 577451, Karnataka, INDIA *Corresponding author e-mail
Matiyar Rahaman Khan - One of the best experts on this subject based on the ideXlab platform.
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Field screening of popular jute (Corchorus spp.) varieties against the major pests in West Bengal, India
South Asian Journal of Experimental Biology, 2012Co-Authors: Sahidur Rahman, Matiyar Rahaman KhanAbstract:Field screening of eight most popular jute varieties belonging to both olitorius and capsularis species was done against the major pests in the farm of Bidhan Chandra Krishi Viswavidyalaya, West Bengal during 2005 and 2006. Among the varieties, JRO‐524 was found to be moderately resistant to Anomis sabulifera and susceptible to Spilarctia obliqua and Myllocerus discolor. The variety JRO‐7835 was moderately resistant to S. obliqua, M. discolor and Polyphagotarsonemus latus but susceptible to A. sabulifera. The variety JRO‐ 632 was found to be highly susceptible to M. discolor but moderately susceptible to other pests. The variety JRO‐878 showed moderate susceptibility to P. latus, A. sabulifera, S. obliqua and Apion corchori but was highly susceptible to M. discolor. Among the capsularis varieties, JRC‐7447 and JRC‐321 were susceptible to A. sabulifera but moderately resistant to other major pests. Variety JRC‐212 was most susceptible to A. corchori but moderately resistant to other pests. The variety JRC‐4444 was found moderately resistant to S. obliqua, A. sabulifera and resistant against M. discolor and P. latus. Further, the fibre production capacity of the varieties under different pest’s pressure was found higher in olitorius varieties than capsularis varieties. The relatively higher yield recorded under varying pest levels over two consecutive seasons is an indicative of greater field tolerance of olitorius jute varieties.
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Evaluation of pesticides against major pests of jute (Corchorus olitorius L.) in West Bengal, India
Archives of Phytopathology and Plant Protection, 2012Co-Authors: Sahidur Rahman, Matiyar Rahaman KhanAbstract:Among the pesticides evaluated against the jute pests under field conditions, endosulfan 35 EC at 350 g a.i./ha was found to be the most effective insecticide for controlling semilooper, Bihar hairy caterpillar and Myllocerus weevil. Endosulfan and fenpropathrin provided good control of yellow mite as well. Even, endosulfan-treated plots gave maximum fibre and stick yield with greater benefit–cost ratio (BCR) over others. Next to endosulfan and chlorpyriphos, neemazal (azadirachtin 50,000 ppm) are useful and safer options against semilooper, Bihar having caterpillar, Myllocerus and yellow mite. Methoxyfenocide 10 EC at 200g a.i./ha provided good control (70.60%) of S. obliqua even after 14 days of spraying, but it was not effective against other pests of jute. Further, almost similar efficacy of neemazal and chlorpyriphos was found against the pest complex of jute and based on BCR, neemazal could be an alternative choice over chlorpyriphos.
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Incidence of pests in jute (Corchorus olitorius L.) ecosystem and pest–weather relationships in West Bengal, India
Archives of Phytopathology and Plant Protection, 2012Co-Authors: Sahidur Rahman, Matiyar Rahaman KhanAbstract:Experiment on jute crop was conducted during pre-kharif to kharif seasons (April to August) at Bidhan Chandra Krishi Viswavidyalaya (BCKV), West Bengal, India in a view to record the pest incidence on olitorius jute and to determine the weather parameters impacting on pest population in jute under West Bengal conditions. Seventeen different species of pests belonging to insects, mites and nematodes were found feeding on jute. Among them, jute semilooper (Anomis sabulifera Guen.), Bihar hairy caterpillar (Spilarctia obliqua Wlk.), grey weevil (Myllocerus discolor Bohemus), yellow mite (Polyphagotarsonemus latus Banks), stem weevil (Apion corchori Marshall), and root knot nematode, Meloidogyne incognita are causing economic damage to the crop and other pests were considered as minor pests. Correlation studies with weather parameters showed that incidence of semilooper was negatively correlated (r = −0.795 to −0.725) with the maximum temperature but had positive significant association with minimum temperatu...
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Effect of plant characteristics of jute varieties on incidence of pests in West Bengal, India
Archives of Phytopathology and Plant Protection, 2012Co-Authors: Sahidur Rahman, Matiyar Rahaman KhanAbstract:This study was conducted with a view to understand the effect of plant characteristics on the incidence of pests on most popular jute varieties, viz. JRO-524, JRO-632, JRO-878, JRO-7835 of olitorius jute and JRC-212, JRC-321, JRC-4444, JRC-7447 of capsularis jute. Correlation studies of plant characteristics with pest incidence in jute (Corchorus spp.) revealed that the basal girth of plant exhibited a positive significant relationship with the incidence of Apion corchori Marshall but not with other pests such as jute semilooper (Anomis sabulifera Guen.), Bihar hairy caterpillar (Spilarctia obliqua Wlk.), grey weevil (Myllocerus discolor Bohemus) and yellow mite (Polyphagotarsonemus latus Banks). However, plant height showed positive correlation with the incidence of all the major pests of jute. Leaf characteristics (number of leaves/plant, leaf area, leaf thickness, moisture and chlorophyll content of leaves of all the varieties recorded at three different growth stages, i.e. at 50, 80 and 110 days after...
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Integrated Management Approach for Control of the Pest Complex of Olitorius Jute, Corchorus Olitorius L.
Journal of Plant Protection Research, 2010Co-Authors: Sahidur Rahman, Matiyar Rahaman KhanAbstract:Field trials were conducted with six treatments against the pest complex of olitorius jute var. JRO-524 during 2004 and 2005 at Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India. The results revealed that incidence of Anomis sabulifera Guen., Spilarctia obliqua Wlk., Myllocerus discolor Bohemus, Apion corchori Marshall and Polyphagotarsonemus latus Banks were found causing a mini- mum of 6.10, 4.68, 12.38, 5.09, and 10.47 percent plant infestation, respectively. These were the results from the 2004 crop season in the IPM module M 3 designed against insect, mite and nematode pests as compared to the other treatments. Similar results were obtained in 2005 with a relatively low plant infestation of 7.66, 28.60, 11.90 and 11.21 caused by A. sabulifera, M. discolor, A. corchori and P. latus, respectively, in module M 3 as compared to the other treatments. The maximum reduction (69.39 to 82.46%) of root-knot nematode (Meloidogyne incognita Chitwood) population along with low gall index (1.33 to 1.67) at harvest was observed in module (M 3 ) in 2004- 05. The yellow mite population was observed to be a minimum of 14.33 and 19.33 per leaf in 2004 and 2005, respectively in M 3 . The maximum average fiber yield of 30.32 q/ha and the benefit-cost ratio of 7.34 were also recorded in M 3. Based on the benefit-cost ratio, the performance of the treatments was in the decreasing order of M 3 > M 2 > M 4 > M 5 > M 1 > M 6 . Considering performance for managing insect, mites and root-knot nematodes, M 3 was the most effective and economical management strategy against the pest complex of olitorius jute. Four spider species viz. Neoscona mukerji Tikader, Neoscona sp., Araneus sp. and Xysticus sp. were recorded for the first time in the jute ecosystem of West Bengal. The pest population in the jute ecosystem could be suppressed naturally to a great extent, because thirteen insects and ten spider predators were encountered in the experimental field during the crop season. Furthermore, a larval parasitoid (Apanteles obliquae) was found acting on the larvae of bihar hairy caterpillars.
H. M. Mahadeva Swamy - One of the best experts on this subject based on the ideXlab platform.
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Expression of cry3A gene and its toxicity against Asian Gray Weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae).
Journal of Basic Microbiology, 2013Co-Authors: H. M. Mahadeva Swamy, Ramasamy Asokan, Geetha G. Thimmegowda, Riaz MahmoodAbstract:Coleopterans are the most damaging pests of many agricultural and forestry crops; there is an urgent need to develop effective biopesticides against these insects. Enhancers of Bt toxicity typify an opportunity to improve currently available commercial products into more effective control agents against diverse pests. A 1.9 kb DNA fragment, PCR amplified from native isolates of Bt using cry3A gene specific primers was cloned in expression vector pQE-80L and then used for transformation of Escherichia coli M15 cells. The sequence of the cloned crystal protein gene showed almost complete homology with a Coleopteran active Cry3A toxin gene with 117 mutations scattered in different domain regions encoding a protein of 645 amino acid residues in length, with a predicted molecular mass of 77.4 kDa. Phylogenetic analysis could be compulsive for new/novel Bacillus thuringiensis strains, allowing them to be grouped with related Cry proteins. The toxicity of Bt protein was determined against Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) LC50 152 ng cm(-2). Genes coding for Coleopteran active Cry3A proteins have been isolated and their efficient expression will provide the tools necessary to increase the efficacy of Cry-based biopesticide against economically important beetles.
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Toxicity of different indigen isolates of Bacillus thuringiensis on mango weevil Myllocerus undecimpustulatus (Coleoptera: Curculionidae)
2013Co-Authors: N. K. Krishnakumar, H. M. Mahadeva Swamy, Riaz MahmoodAbstract:Division of Entomology and Nematology, Indian Institute of Horticultural Research (IIHR), Hessaraghatta lake post, Bangalore 560089, Karnataka, INDIA Division of Horticulture, Krishi Anusandhan Bhawan II, New Delhi 110 012 INDIA Division of Biotechnology, Indian Institute of Horticultural Research (IIHR), Hessaraghatta lake post, Bangalore 560089, Karnataka, INDIA Post-Graduate Department of Studies and Research in Biotechnology and Bioinformatics, Kuvempu University, Jnanasahayadri, Shankaraghatta, Shimoga 577451, Karnataka, INDIA *Corresponding author e-mail
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Isolation, Molecular Characterization and Expression of a New Cry 3a Gene from Native Isolates of Bacillus thuringiensis and Its Toxicity Against Asian Grey Weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae)
Prospects in Bioscience: Addressing the Issues, 2012Co-Authors: H. M. Mahadeva Swamy, Riaz Mahmood, Ramasamy Asokan, Geetha G. Thimmegowda, Dilip K. AroraAbstract:The genetic diversity and distribution of cry genes in Bacillus thuringiensis strains vary based on geographical location. Each habitat may contain novel B. thuringiensis isolates that have more toxic effects on target spectra of insects. To obtain novel B. thuringiensis strains for the production of Cry proteins, isolation of numerous new B. thuringiensis strains is becoming a routine activity in many industries. The B. thuringiensis Cry3A gene is regulated by a different mechanism from that of most of the other cry genes. 1.935-kb DNA fragment of Cry3A gene was PCR amplified using gene-specific primers, cloned in expression vector pQE-80 L and then used for transformation of E. coli M15 cells. The optimum expression was obtained with 1 mM IPTG at 37°C for 3 h. Nucleotide sequencing of the Cry3A gene revealed an open reading frame of 1,935 bp, encoding a protein of 645 amino acid residues in length, with a predicted molecular mass of 77.4 kDa. These full-length gene sequences were deposited at NCBI GenBank with accession number JQ038134 and JQ038135. Present work is now being directed toward the isolation and expression of the new Cry3A gene to access its effect against Asian grey weevil Myllocerus undecimpustulatus undatus (Coleoptera: Curculionidae). The availability of the recombinant protein will also allow the isolation and identification of its receptor in the insect midgut. Additionally, novel activities/specificities based on the sequence of the new Cry3A gene can be explored by the use of techniques such as DNA shuffling or point mutations. This system offers an additional method for potentially improving the efficacy of Bt insecticidal proteins efficiently, stably, and safely particularly against anti-lepidopteran insect pests. In other words, Bt technology will be a key to future growth of agriculture.
Ramasamy Asokan - One of the best experts on this subject based on the ideXlab platform.
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Molecular characterization and elucidation of Bacillus thuringiensis Cry1I toxin isolated from the insect pest mango leaf webber, Orthaga exvinacea (Noctuidae: Lepidoptera)
Journal of entomology and zoology studies, 2020Co-Authors: Govindan Selvakumar, Ramasamy Asokan, G. Nagalakshmi, Br Soumya, Abraham VergheseAbstract:A new full-length Bacillus thuringiensis cry1I type gene was isolated from the mango leaf webber (Orthaga exvinacea) that was naturally infested. And its sequence of nucleotides was determined. The new Cry1I protein's deduced amino acid sequence is identical with Cry1b (94%) and Cry1Ia (89%) toxins. NCBI GenBank's accession number was given to the nucleotide sequence of the new cry1I gene: KJ437512 (partial) and KJ437513, showing 93-99 percent homology with Cry1I toxins genes previously published. Bt_MLB_Cry1I 3D toxin homology model was developed, despite low sequence identity with its structural homologues, Cry1I not only resembles the previously reported Cry toxin structures but also shares the typical five conserved amino acid residue blocks and subsequently evaluates the 3D model using bioinformatics tools. Mixtures of spores/inclusions of the Bt-_MLB_Cry1I were tested for their toxicity against adults of brinjal ash weevil Myllocerus subfasciatus (Coleoptera: Curculionidae). In accordance with standard reference strains, adult mortality rates caused by spore and crystalline inclusion are 100 percent. The observed 100% mango leaf webber infestation to Bt in natural condition is a rare report indicating naturally high strain anti-lepidopterone activity. The increase in the number of Bt collections has resulted in an increase in the discovery of new Bt isolates with insecticide activity against a variety of insects or with increased insecticide activity. The current study has extended the potential for the management of Coleopteran pests to collect promising Bt isolates from naturally infected insect pests from different origins.
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Diversity analysis and characterization of Coleoptera-, Hemiptera- and Nematode-active cry genes in native isolates of Bacillus thuringiensis
Annals of Microbiology, 2014Co-Authors: Ramasamy Asokan, Geetha G. Thimmegowda, Hanchipura Mallesh Mahadeva Swamy, Riaz MahmoodAbstract:Applications to combat non-lepidopteran insects are not as common as applications against lepidopteran insects. The aim of the present work was to isolate and identify Bacillus thuringiensis isolates from soil samples using five approaches, viz., analysis of crystal protein production by microscopy; detection of cry gene content by PCR, SDS-PAGE profiling; cloning and sequencing; phylogenetic analysis; and toxicity testing. Two hundred soil samples were used for isolation of B. thuringiensis and a total of 69 putative isolates of B. thuringiensis that produce parasporal crystalline inclusions were isolated from 5,267 Bacillus -like colonies. A bipyramidal inclusion was predominant in 32.2 % of the B. thuringiensis isolates compared to other shapes. Crystal protein profiling of B. thuringiensis isolates by SDS-PAGE analysis showed the presence of bands of 130, 73, 34, 25 and 13 kDa, among which 50–60 kDa bands were present abundantly. PCR analysis revealed the predominance of Coleopteran-active cry genes in these isolates. Variation in nucleotide sequences, crystal morphology and mass of crystal protein(s) purified from the isolates of B. thuringiensis revealed genetic and molecular diversity. Four strains containing Coleopteran-active cry genes showed higher toxicity against Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) adults when compared with B. thuringiensis subsp. morrisoni pathovar tenebrionis . These results are useful in emphasizing the distribution of cry genes and for prognostication of toxicity, and may contribute to the identification of novel candidate genes for bioengineered crop protection.
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Expression of cry3A gene and its toxicity against Asian Gray Weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae).
Journal of Basic Microbiology, 2013Co-Authors: H. M. Mahadeva Swamy, Ramasamy Asokan, Geetha G. Thimmegowda, Riaz MahmoodAbstract:Coleopterans are the most damaging pests of many agricultural and forestry crops; there is an urgent need to develop effective biopesticides against these insects. Enhancers of Bt toxicity typify an opportunity to improve currently available commercial products into more effective control agents against diverse pests. A 1.9 kb DNA fragment, PCR amplified from native isolates of Bt using cry3A gene specific primers was cloned in expression vector pQE-80L and then used for transformation of Escherichia coli M15 cells. The sequence of the cloned crystal protein gene showed almost complete homology with a Coleopteran active Cry3A toxin gene with 117 mutations scattered in different domain regions encoding a protein of 645 amino acid residues in length, with a predicted molecular mass of 77.4 kDa. Phylogenetic analysis could be compulsive for new/novel Bacillus thuringiensis strains, allowing them to be grouped with related Cry proteins. The toxicity of Bt protein was determined against Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) LC50 152 ng cm(-2). Genes coding for Coleopteran active Cry3A proteins have been isolated and their efficient expression will provide the tools necessary to increase the efficacy of Cry-based biopesticide against economically important beetles.
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Isolation, Molecular Characterization and Expression of a New Cry 3a Gene from Native Isolates of Bacillus thuringiensis and Its Toxicity Against Asian Grey Weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae)
Prospects in Bioscience: Addressing the Issues, 2012Co-Authors: H. M. Mahadeva Swamy, Riaz Mahmood, Ramasamy Asokan, Geetha G. Thimmegowda, Dilip K. AroraAbstract:The genetic diversity and distribution of cry genes in Bacillus thuringiensis strains vary based on geographical location. Each habitat may contain novel B. thuringiensis isolates that have more toxic effects on target spectra of insects. To obtain novel B. thuringiensis strains for the production of Cry proteins, isolation of numerous new B. thuringiensis strains is becoming a routine activity in many industries. The B. thuringiensis Cry3A gene is regulated by a different mechanism from that of most of the other cry genes. 1.935-kb DNA fragment of Cry3A gene was PCR amplified using gene-specific primers, cloned in expression vector pQE-80 L and then used for transformation of E. coli M15 cells. The optimum expression was obtained with 1 mM IPTG at 37°C for 3 h. Nucleotide sequencing of the Cry3A gene revealed an open reading frame of 1,935 bp, encoding a protein of 645 amino acid residues in length, with a predicted molecular mass of 77.4 kDa. These full-length gene sequences were deposited at NCBI GenBank with accession number JQ038134 and JQ038135. Present work is now being directed toward the isolation and expression of the new Cry3A gene to access its effect against Asian grey weevil Myllocerus undecimpustulatus undatus (Coleoptera: Curculionidae). The availability of the recombinant protein will also allow the isolation and identification of its receptor in the insect midgut. Additionally, novel activities/specificities based on the sequence of the new Cry3A gene can be explored by the use of techniques such as DNA shuffling or point mutations. This system offers an additional method for potentially improving the efficacy of Bt insecticidal proteins efficiently, stably, and safely particularly against anti-lepidopteran insect pests. In other words, Bt technology will be a key to future growth of agriculture.
Stephen L. Lapointe - One of the best experts on this subject based on the ideXlab platform.
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Biology, Chemical Ecology, and Sexual Dimorphism of the Weevil Myllocerus undecimpustulatus undatus (Coleoptera: Curculionidae)
Florida Entomologist, 2019Co-Authors: Justin George, Sana Shareef, Stephen L. LapointeAbstract:Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae), also known as the Sri Lankan weevil, is becoming a major pest of ornamentals and tropical fruit trees in the southern USA, including Florida. Recent findings of this species in Florida citrus groves justify research into its biology and ecology. We studied morphological and sexually dimorphic characters of this species as an aid to rapid separation of sexes for studies aiming to identify semiochemicals that may be of value in management. Female weevils collected from the field in southeastern Florida were significantly larger than males in length of head, abdomen, and overall length. Females, but not males, have a characteristic black-gray marking extending from the ventral mesosternum to the second abdominal segment. Scanning electron microscopic images revealed that females had fewer ovate-to-obovate scales in this region of characteristic black-gray marking, and more plumose scales compared with males. Host choice and oviposition studies showed that Sri Lankan weevils prefer peach plants over weeds or grasses in peach orchards. Electroantennogram recordings with different peach volatiles identified peach odorants that can elicit significantly higher antennal responses. Both male and female Sri Lankan weevil antennae were highly responsive to these volatiles. Behavioral assays in olfactometers are underway to identify those semiochemicals that could be used as attractants or disruptants.
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Morphology and Sexual Dimorphism of the Weevil Myllocerus undecimpustulatus undatus (Coleoptera: Curculionidae)
Annals of The Entomological Society of America, 2015Co-Authors: Justin George, William C. Morse, Stephen L. LapointeAbstract:ABSTRACT Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae), also known as the Sri Lankan weevil, is becoming a major pest of ornamentals and tropical fruit trees in the southern states of United States, especially in Florida. Recent findings of this species in Florida citrus groves justify research into their biology and ecology. Identification of semiochemicals involved in their behavioral and chemical communication will help to develop insect control strategies. We studied morphological and sexually dimorphic characters of this species as an aid to rapid separation of sexes for studies aiming to identify semiochemicals that may be of value in management. Female weevils collected from the field in southeastern Florida were significantly larger than males in length of head, abdomen, and overall length. Females weight was approximately twice that of males. No significant differences in the distance between procoxal or mesocoxal articulations observed between males and females. But t...
