33 public questions tagged with this topic.
Bacillus thuringiensis (Bt) toxin provides resistance to insect pests, reducing the need for chemical pesticides. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Biology - Zoology portion covering relevant system and function.
Micropropagation is a tissue culture technique used to produce large numbers of genetically identical plants from a single tissue or ll. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Structural Organisation in Animals and Frog, Topic: Tissues, skeletal and organ systems.
Sucrose provides the energy required for the growth and development of plant lls in tissue culture media. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Structural Organisation in Animals and Frog, Topic: Tissues, skeletal and organ systems.
crtI gene deployed in Golden Rice was sourced from soil bacterium Erwinia uredovora strain now taxonomically reclassified as Pantoea ananatis, a Gram-negative enterobacterium inhabiting plant surfaces capable of synthesizing carotenoids as photoprotective pigments. Gene encodes 489 amino acid phytoene desaturase with FAD binding domain catalyzing sequential introduction of four double bonds into phytoene backbone converting 15-cis-phytoene via phytofluene, zeta-carotene, neurosporene to all-trans lycopene with concomitant isomerization, effectively replacing plant PDS, ZDS, CRTISO functions. B
Ref: Sandmann Eur J Biochem 1994 crtI bacterial; NCBI Gene crtI Pantoea; Beyer PNAS 2000.
Original Golden Rice event employed phytoene synthase gene cloned from Narcissus pseudonarcissus, common daffodil, a monocot bulbous geophyte storing high carotenoid levels in chromoplasts of perianth flowers bright yellow. Daffodil psy cDNA was available, well characterized, and known to encode plastid-localized enzyme with high activity converting GGPP to phytoene. Its coding sequence fused to endosperm-specific glutelin promoter Gt1 and pea rbcS transit peptide sequence MSMA to direct import into plastids via Toc-Tic translocon machinery. Expression in rice endosperm complemented missing en
Ref: Ye et al. Science 2000 Daffodil psy; Paine et al. 2005 Maize psy improvement; Plant Physiol.
Development of Golden Rice elegantly reduced complex plant carotenoid desaturation steps to two transgenes. Phytoene synthase psy catalyzes committed head-to-head condensation of two geranylgeranyl diphosphate GGPP molecules to colorless 15-cis-phytoene, rate limiting step strongly regulated by light and feedback. Phytoene requires four desaturation steps and isomerization to become all-trans lycopene red pigment. Higher plants use phytoene desaturase, zeta-carotene desaturase, carotene isomerase ZDS, CRTISO separately. Bacterial crtI from Erwinia uredovora performs all reactions in single pol
Ref: Beyer et al. J Nutr 2002 Golden Rice pathway; NCBI Metabolic pathway psy crtI mechanism.
Cry proteins form parasporal crystals during sporulation, requiring solubilization at high pH and proteolytic activation. Vip proteins differ temporally and biochemically. Vip1, Vip2, Vip3 secreted during exponential vegetative growth into culture supernatant, not associated with spores. Vip3A, most agriculturally relevant, shares no sequence homology with Cry domains, presents unique tetrameric structure and binds distinct receptors including scavenger receptor class C and fibroblast growth factor receptor-like protein, triggering apoptosis pathway in addition to pore formation. Activity prim
Ref: Estruch PNAS 1996 Vip vegetative; Donovan 2001 Vip3 structure; Yu Appl Environ Microbiol 1997 differences; PubMed 8855281 vegetative insecticidal proteins.
International Service for Acquisition of Agri-biotech Applications annually reports global adoption of GM crops. Historical data from 1996 to 2023 demonstrates herbicide tolerance trait dominates both by trait type and crop species. Among crops, soybean engineered for glyphosate tolerance occupied largest area, reaching over 94 million hectares in 2019, accounting for about half of all GM hectarage. Drivers include high demand for protein meal for animal feed, suitability of herbicide tolerance for large-scale mechanized farming in United States, Brazil, Argentina, adoption of no-till practice
Ref: ISAAA Brief 55 2019 global status herbicide tolerant soybean dominant; James ISAAA 2014; NCBI NBK131103 statistics; https://www.isaaa.org/resources/publications/briefs/55/
Suspension cultures differ from callus grown on agar by continuous agitation ensuring homogeneous nutrient and gas distribution and removal of growth inhibitors. Inoculation of friable callus fragments into Erlenmeyer flasks on orbital shaker at 110 rpm disperses cells, creates single cells and small aggregates suitable for growth kinetic measurements, mutant selection, and bioreactor scale-up. Uniform cell size allows precise biomass estimation by packed cell volume and dry weight, enabling process control for large-scale production of cells for biochemical studies, somatic embryogenesis, art
Ref: Murashige & Skoog 1962 suspension; Street 1977 suspension methods; NCBI NBK26844 large scale; Phillips Plant Cell Culture 2010 bioreactor.
Agrobacterium plasmids determine disease phenotype. Ti plasmid, tumor-inducing, contains T-DNA with iaaM, iaaH, and ipt genes overproducing auxin and cytokinin, causing undifferentiated gall. Ri plasmid, root-inducing, carries TL and TR T-DNA regions in agropine strains; TL harbors rol cluster essential for hairy root syndrome and TR carries auxin genes and agropine synthesis. Virulence region mediates T-strand excision and transfer via type IV secretion. Upon integration, rol gene expression modifies host signaling, stimulating root proliferation rather than callus. Laboratory disarmed Ri vec
Ref: White & Nester J Bacteriol 1980 Ri structure; Nilsson & Olsson Physiol Plant 1997 rol; NCBI NBK21414 Ti vs Ri; https://www.ncbi.nlm.nih.gov/books/NBK21414/
Hairy root syndrome originates when wounded dicot tissue is invaded by soil bacterium carrying root inducing plasmid. Transfer of T-DNA segment harboring rolA, rolB, rolC, rolD loci plus opine synthesis genes into host chromosome rewires hormone balance. rolB encodes tyrosine phosphatase increasing auxin sensitivity, rolC cytokinin glucosidase adjusting growth, together triggering extensive adventitious root emergence directly from callus. Roots grow plagiotropically, highly branched, hormone independent, and genetically stable for decades. In contrast Agrobacterium tumefaciens produces crown
Ref: Chilton Nature 1982 Ri plasmid; Tepfer PNAS 1984 hairy root; NCBI NBK21344 rol genes; PubMed 17302573 hairy root review 2014.
Elicitors boost secondary metabolite production by mimicking biotic attack triggering plant innate defense signaling and activation of defence related enzymes. Biotic elicitors include fungal cell wall fragments chitin chitosan glucans yeast extract bacterial flagellin; abiotic include jasmonic acid methyl jasmonate salicylic acid heavy metals copper cadmium UV-C ozone. Perception by pattern recognition receptors triggers calcium influx cyclic nucleotide gated channels, production of reactive oxygen species via NADPH oxidase RBOH, activation of mitogen activated protein kinase cascades MPK3 MP
Ref: Ramachandra & Ravishankar Plant Cell Rep 2002 elicitors; Nature Plants secondary metabolism.
