A Technique to Enhance Bacillus thuringiensis Spectrum and Control Efficacy Using Cry Toxin Mixture and Immunosuppressant

As proteínas Cry produzidas pela bactéria entomopatogênica Bacillus thuringiensis Berliner são bem conhecidas devido a alta citotoxicidade que exibem a uma variedade de insetos-alvo. O modo de ação destas proteínas é específico e torna os produtos à base de B. thuringiensis os mais amplamente utilizados em programas de controle biológico de pragas na agricultura e de importantes vetores de doenças humanas. Contudo, embora as proteínas Cry sejam os fatores de virulência inseto-específico mais conhecidos, linhagens de B. thuringiensis apresentam também uma ampla gama de fatores de virulência, os quais permitem à bactéria atingir a hemolinfa e colonizar eficientemente o inseto hospedeiro. Dentre estes fatores, destacam-se as proteínas Vip, Cyt, enterotoxinas, hemolisinas, fosfolipases, proteases, enzimas de degradação, além das recentemente descritas parasporinas. Essa revisão aborda a ação desses fatores de virulência, bem como a caracterização e o controle da expressão de seus genes. Adicionalmente, são discutidos aspectos relacionados ao nicho ecológico da bactéria com ênfase nas características envolvidas com a biossegurança da utilização dos produtos à base de B. thuringiensis para o controle biológico de insetos-alvo. Virulence Factors of Bacillus thuringiensis Berliner: Something Beyond of Cry Proteins? Abstract. The Cry proteins produced by the entomopathogenic bacterium Bacillus thuringiensis Berliner are widely known due to its high toxicity against a variety of insects. The mode of action of these proteins is specific and becomes B. thuringiensis-based products the most used in biological control programs of insect pests in agriculture and of important human disease vectors. However, while the Cry proteins are the best-known insect-specific virulence factor, strains of B. thuringiensis show also a wide range of other virulence factors, which allow the bacteria to achieve the hemolymph and colonize efficiently the insect host. Among these factors, we highlight the Vip proteins, Cyt, enterotoxins, hemolysins, phospholipases, proteases and enzymes of degradation, in addition to the recently described parasporin. This review explores the action of these virulence factors, as well as, the characterization and control of expression of their genes. Additionally, we discuss aspects related to the ecological niche of the bacteria with emphasis on the characteristics involved in the biosafety of the use of B. thuringiensis-based products for biological control of target insects.

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IDENTIFIKASI DAN UJI PENGENDALIAN HAMA DAUN JABON SECARA INVITRO

Jurnal Sains Natural ◽

10.31938/jsn.v4i1.75 ◽

2017 ◽

Vol 4 (1) ◽

pp. 51

Author(s):

Ujang W. Darmawan ◽

Agus Ismanto

Keyword(s):

Bacillus Thuringiensis ◽

Pest Species ◽

Control Test ◽

Control Effort ◽

Tukey Test ◽

Randomized Design ◽

Completely Randomized Design ◽

Biological Pesticide ◽

And Control ◽

Organic Pesticides

Identification and Control Test of Jabon Leaf Pest by Invitro One of problem in jabon (Neolamarckia cadamba [Roxb.] F. Bosser) plantation is defoliator. Identification and control effort are needed to counter this problem. This research was intended to identify pest species attacking plant and do efficacy test of several chemical and biological pesticides against the defoliator. The statistical method of efficacy was Completely Randomized Design (CRD). Two pesticides prophenophos (0,1%) and dimethoate (0,1%) as chemical based organic pesticides and Bacillus thuringiensis(0,5 g/l) as biological pesticide were tested against the defoliator. Data was analyzed using Anova and Tukey test at 95% confidence level. The result showed that pest was identified as Dysarthria quadricaudata. Chemical and biological pesticides were effective to control the pest.Keywords: Neolamarckia cadamba, Dysarthria quadricaudata, prophenophos, dimethoate, pest. ABSTRAK Salah satu persoalan pada hutan tanaman jabon (Neolamarckia cadamba [Roxb.] F. Bosser) adalah serangan hama perusak daun. Pengendalian diperlukan untuk mengatasi persoalan ini. Penelitian bertujuan untuk mengidentifikasi spesies hama dan melakukan efikasi beberapa jenis pestisida kimia dan organik terhadap hama ulat daun jabon (N. cadamba). Metode yang digunakan adalah rancangan acak lengkap. Dua jenis pestisida kimia berbahan profenofos (0,1%), dan dimetoat (0,1%) serta pestisida organik berbahan dasar Bacillus thuringiensis (0,5 gr/lt) diuji terhadap hama ulat daun. Data dianalisis menggunakan Anova dan uji Tukey (CI = 95%). Hasil penelitian menunjukkan bahwa spesies hama yang menyerang tanaman jabon adalah Dysarthria quadricaudata. Jenis pestisida tersebut efektif mengendalikan hama ulat daun jabon.Kata kunci: Neolamarckia cadamba, Dysarthria quadricaudata, profenofos. dimetoat, hama

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Seasonal Occurrence of Tetranychus kanzawai and Control Efficacy of Alternate Use of Natural Enemy and Miticide in Rubus coreanus Field

Korean journal of applied entomology ◽

10.5656/ksae.2010.49.3.233 ◽

2010 ◽

Vol 49 (3) ◽

pp. 233-239 ◽

Cited By ~ 3

Author(s):

Ju-Rak Lim ◽

Jin You ◽

Seong-Soo Cheong ◽

Dong-Chil Choi ◽

Chang-Yeon Hwang

Keyword(s):

Natural Enemy ◽

Seasonal Occurrence ◽

Tetranychus Kanzawai ◽

Control Efficacy ◽

Rubus Coreanus ◽

And Control

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Engineering of Bacillus thuringiensis Cry Proteins to Enhance the Activity against Western Corn Rootworm

Toxins ◽

10.3390/toxins11030162 ◽

2019 ◽

Vol 11 (3) ◽

pp. 162 ◽

Cited By ~ 3

Author(s):

Jingtong Hou ◽

Ruth Cong ◽

Michi Izumi-Willcoxon ◽

Hana Ali ◽

Yi Zheng ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

3D Structure ◽

Diabrotica Virgifera Virgifera ◽

Western Corn Rootworm ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Cry Protein ◽

Neutral Ph ◽

Highly Active ◽

Cry Toxin

A novel Bacillus thuringiensis Cry protein, Cry8Hb, active against Diabrotica virgifera virgifera (Western corn rootworm, WCRW) was discovered. Unexpectedly, the anti-rootworm activity of the Cry8Hb toxin was enhanced significantly by fusing Escherichia coli maltose binding protein (MBP) to this Cry toxin. While the exact mechanism of the activity enhancement remains indefinite, it is probable that the enhancement is a result of increased solubility of the MBP-Cry8Hb fusion in the rootworm midgut. This hypothesis was examined using a synthetic Cry3 protein called IP3-1, which was not soluble at a neutral pH like Cry8Hb and marginally active to WCRW. When IP3-1 was fused to MBP, its anti-WCRW activity was enhanced 13-fold. To further test the hypothesis, DNA shuffling was performed on IP3-1 to increase the solubility without MBP. Screening of shuffled libraries found six new IP3 variants showing very high anti-WCRW activity without MBP. Sequence and 3D structure analysis of those highly active, shuffled IP3 variants revealed several charge-altering mutations such as Lys to Glu on the putative MBP-attaching side of the IP3 molecule. It is likely that those mutations make the protein acidic to substitute the functions of MBP including enhancing the solubility of IP3 at a neutral pH.

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Comparison of the efficacy of QoI fungicides, alone or in mixture with triazoles, in Asian soybean rust control, 2016/17 growing season

Summa Phytopathologica ◽

10.1590/0100-5405/190157 ◽

2019 ◽

Vol 45 (1) ◽

pp. 28-32 ◽

Cited By ~ 1

Author(s):

Erlei Melo Reis ◽

Luis Henrique Carregal ◽

Mateus Zanatta

Keyword(s):

Grain Yield ◽

Soybean Rust ◽

Phenological Stages ◽

Control Efficacy ◽

Qoi Fungicides ◽

Asian Soybean Rust ◽

Progress Curve ◽

Crop Cycle ◽

And Control ◽

Positive Effect

ABSTRACT Evolution has been reported for the reduction in Phakopsora pachyrhizi sensitivity to the mixtures of the three site-specific mechanisms of action (DMIs, QoIs and SDHIs) used in its control. The aim of this study was to quantify the current contribution of QoIs, alone or in mixture with triazoles, in the control of Asian soybean rust. In an experiment carried out in the field, the efficacy of quinone outside inhibitors (QoIs), or strobilurins, was compared for Asian soybean rust control. The isolated effects of four doses of azoxystrobin, picoxystrobin, pyraclostrobin and trifloxystrobin were evaluated, as well as of four applications during the crop cycle. Control by commercial mixtures of these QoIs with triazoles was also compared. Severity was evaluated in four phenological stages, and control was calculated based on final severity data, area under rust progress curve, defoliation, one-thousand-grain mass, grain yield and damage caused by the disease. The lowest mean of rust control efficacy resulted from applications of azoxystrobin (15.8 and 11.19%) and pyraclostrobin (15.4 and 16.76%) and the highest mean was found for picoxystrobin (54.1 and 54.35 %) and trifloxystrobin (69.7 and 64.46%), calculated based on final severity and AUDPC, respectively. Such efficacy is not enough to cover the fungicide application cost, although there was a positive effect of treatments on disease control and grain yield.

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