Articles written in Journal of Biosciences
Volume 45 All articles Published: 30 January 2020 Article ID 0031 Article
High-yielding Indian cotton varieties are not amenable for regeneration and transformation because they arerecalcitrant in nature. In this work, we have developed Narasimha (NA1325) cotton variety by introducing three Crygenes driven by three different promoters conferring insect resistance. The meristematic region of embryo axisexplants were infected and co-cultivated with Agrobacterium tumefacience (LBA4404) harbouring pMDC100vector with three Cry gene cassettes (a-globulin : Cry2Ab, DECaMV35s : Cry1F and nodulin : Cry1Ac) with Npt IIas a selectable marker gene. Out of 1010 embryo axes explants infected, 121 (T0) regenerated under two rounds ofkanamycin selectionmedium.About 2551T1 seedswere collected from111T0 plants and these seeds screened againwith kanamycin at seedling stage. The transgenic plants were characterized by PCR, real time quantitative PCR,lateral flow strip protein assay and insect bioassay. Out of 145 kanamycin resistant plants (T1), twelve showedamplification of all four transgenes: Npt II, Cry2Ab, Cry1F and Cry1Ac through PCR with expected amplicons as395, 870, 840 and 618 bp, respectively. Further, lateral flow strip test revealed Cry1F and Cry1Ac proteinsaccumulated in 12 plants, whereas Cry2Ab protein was detected in eight only. The transcripts of all three Cry geneswere accumulated significantly higher in transgenic plants at T2 generation. The transgenic lines showed effectiveresistance againstHelicoverpa armigera and Spodoptera litura larvae. The T2 line L-3 exhibited highest percentageof insect mortality, in which transcripts of all cry genes were accumulated higher than other plants. The transgeniccotton plants carrying triple Cry genes could be an excellent germplasmresource for the breeders for introgressions.
Volume 45 All articles Published: 17 September 2020 Article ID 0114 Review
Phytophagous insect incidence is a serious threat for reduction of crop productivity globally. There is anestimation of one fourth of crop is being destroyed by insects annually. Indeed, the development of insect resistantcrops 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 delta-endotoxins andvegetative insecticidal proteins and other plant genes like lectins, protease inhibitors, etc. In addition, RNAinterference and genome editing through CRISPR Cas9 also provides new solutions for the development ofinsect-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 impactworldwide in terms of higher yield and low pesticide usage. In this review, we focus on different strategies fordeveloping transgenics against insect pest control by expressing different insecticidal proteins in crops.
Volume 46, 2021
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