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Book ChapterDOI

Agrobacterium-Mediated Transformation for Insect-Resistant Plants

01 Jan 2019-pp 275-283

TL;DR: Bacillus thuringiensis (Bt) is considered as gram-positive, aerobic, spore-forming, naturally occurring facultative soilborne bacterial pathogen and has been used for natural insect control and produces a parasporal, persistent insecticidal protein crystals (ICPs).

AbstractBacillus thuringiensis (Bt) is considered as gram-positive, aerobic, spore-forming, naturally occurring facultative soilborne bacterial pathogen and has been used for natural insect control. It produces a parasporal, persistent insecticidal protein crystals (ICPs). These ICPs are toxic in nature for a class of lepidopterans, dipterans, and coleopterans. That toxic protein differs, depending on the subspecies of Bt producing it. The most prevalent ICPs are the Cry (crystal) protein, and the other is Cty (cytolytic) protein produced by some Bacillus thuringiensis stains. The Cry proteins, in general were cleaved by proteolytic enzymes on intake to produce active toxins which results in osmotic imbalance, lysis of epithelial cells, and finally death due to starvation, whereas Cty proteins release vegetative insecticidal proteins (VIPs) which lead to membrane disruptions, midgut lysis, and paralysis in lepidopterans pests. The use of ICPs as a pesticide or insecticide over chemicals is more beneficial as there is less amount of environmental pollution and harmful chemical residues leaching into the soil and water bodies. It is also target specific and acts on specific class of pests and at the same time harmless to birds, fish, and mammals whose acidic gut conditions negate the bacteria’s effect.

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Journal ArticleDOI
TL;DR: In vivo redox biosensing resolves the spatiotemporal dynamics of compartmental responses to local ROS generation and provide a basis for understanding how compartment-specific redox dynamics may operate in retrograde signaling and stress 67 acclimation in plants.
Abstract: In experiments with tobacco tissue cultured on White's modified medium (basal meditmi hi Tnhles 1 and 2) supplemenk'd with kiticthi and hidoleacctic acid, a slrikin^' fourlo (ive-told intTease iu yield was ohtaitu-d within a three to Tour week j^rowth period on addition of an aqtteotis exlrarl of tobacco leaves (Fi^'ures 1 and 2). Subse(iueutly it was found Ihiit this jnoniotiou oi' f^rowih was due mainly though nol entirely to inorj^auic rather than organic con.stitttenls in the extract. In the isolation of Rrowth factors from plant tissues and other sources inorj '̂anic salts are fre(|uently carried along with fhe organic fraclioits. When tissue cultures are used for bioassays, therefore, il is necessary lo lake into account increases in growth which may result from nutrient elements or other known constituents of the medium which may he present in the te.st materials. To minimize interference trom rontaminaitis of this type, an altempt has heen made to de\\eh)p a nieditmi with such adequate supplies of all re(iuired tnineral nutrients and cotntnott orgattic cottslitueitls that no apprecial»le change in growth rate or yield will result from the inlroduclion of additional amounts in the range ordinarily expected to be present in tnaterials to be assayed. As a point of referetice for this work some of the culture media in mc)st common current use will he cotisidered briefly. For ease of comparis4)n Iheir mineral compositions are listed in Tables 1 and 2. White's nutrient .solution, designed originally for excised root cultures, was based on Uspeuski and Uspetiskaia's medium for algae and Trelease and Trelease's micronutrieni solution. This medium also was employed successfully in the original cttltivation of callus from the tobacco Iiybrid Nicotiana gtauca x A', tanijadorffii, atitl as further modified by White in 194̂ ^ and by others it has been used for the

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TL;DR: A large number of morphologically normal, fertile, transgenic rice plants were obtained by co-cultivation of rice tissues with Agrobacterium tumefaciens, and sequence analysis revealed that the boundaries of the T-DNA in transgenic Rice plants were essentially identical to those intransgenic dicotyledons.
Abstract: Summary A large number of morphologically normal, fertile, transgenic rice plants were obtained by co-cultivation of rice tissues with Agrobacterium tumefaciens The efficiency of transformation was similar to that obtained by the methods used routinely for transformation of dicotyledons with the bacterium Stable integration, expression and inheritance of transgenes were demonstrated by molecular and genetic analysis of transformants in the R0, R1 and R2 generations Sequence analysis revealed that the boundaries of the T-DNA in transgenic rice plants were essentially identical to those in transgenic dicotyledons Calli induced from scutella were very good starting materials A strain of A tumefaciens that carried a so-called ‘super-binary’ vector gave especially high frequencies of transformation of various cultivars of japonica rice that included Koshihikari, which normally shows poor responses in tissue culture

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Abstract: The experiments have revealed that (NH4)2SO4 combined with KNO3 at low concentration is of advantage to the formation, growth and differentiation of pollen callus in rice, whereas the high concentration of (NH4)2SO4, whether used separately or in combination with KNO3, obviously inhibits the pollen callus formation. The optimum NH4+ concen- tration is about 7.0 mM (equal to 3.5 mM (NH4)2SO4). A basic medium containing 3.5 mM (NH4)2SO4 and 28 mM KNO3 as nitrogen sources has been established. On such medium the frequency of the pollen callus formation is higher than that on Millers me- dium, and the differentiation of shoot from pollen callus is satisfactory.

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