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#Roundup Ready crops

2 public questions tagged with this topic.

Transgenic Plant -1

EPSPS gene used in Roundup Ready crops was obtained from:

Glyphosate tolerance technology relies on EPSPS variant showing high glyphosate insensitivity while retaining catalytic activity. Soil bacteria from glyphosate production plant waste in Louisiana screened for EPSPS activity in presence of herbicide identified Agrobacterium sp. strain CP4, now classified as Agrobacterium tumefaciens, harboring class II EPSPS naturally tolerant due to structural changes in active site reducing binding affinity. Gene cloned, sequenced, and fused to chloroplast transit peptide from petunia EPSPS and enhanced 35S promoter, introduced into crops via Agrobacterium mediated transformation. Protein CP4 EPSPS shares only 50 percent homology with plant EPSPS but performs same reaction synthesizing EPSP. Expression provides bypass enzyme maintaining aromatic amino acid flux during herbicide treatment. Functional equivalence confirmed by animal feeding studies. Commercial events such as GTS 40-3-2 soybean carry this bacterial gene, demonstrating successful bioprospecting from soil microbes to develop broad-spectrum herbicide tolerance trait deployed in Roundup Ready systems worldwide. Molecular characterization shows CP4 EPSPS 455 amino acids, 47.6 kDa, with Km for PEP 12 micromolar similar to plant enzyme but Ki for glyphosate 2500-fold higher due to substitution of alanine at position equivalent to Gly100 in E. coli EPSPS, altering active site volume reducing glyphosate binding. Gene codon optimized for plant

Ref: Barry US Patent 5633435 CP4 EPSPS; Funke PNAS 2006 structure; NCBI NBK131103 Agrobacterium CP4; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1482475/

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Transgenic Plant -1

Roundup Ready crops are resistant to:

Roundup Ready is brand name for transgenic crops tolerant to glyphosate based herbicide Roundup. Native crop EPSPS inhibited by glyphosate application, blocking aromatic amino acid synthesis. Incorporation of insensitive EPSPS variant allows continued pathway function despite spray, enabling post-emergence weed control without crop injury. Crops carrying cp4-epsps gene survive broadcast over-the-top application at commercial rates, simplifying weed management and facilitating conservation tillage reducing soil erosion. Soybean, cotton, maize, canola, alfalfa, and sugar beet versions deregulated globally. Resistance not based on detoxification but target site insensitivity, so herbicide still translocates systemically killing weeds. Development of Roundup Ready revolutionized agriculture in late 1990s, dominating transgenic acreage. Stewardship challenges include evolution of glyphosate resistant weeds after continuous monoculture and reliance on single mode of action. Therefore Roundup Ready crops are resistant to glyphosate herbicide through expression of tolerant EPSPS enzyme. Adoption history began 1996 with Roundup Ready soybean event GTS 40-3-2 developed by Monsanto, followed by cotton, maize. Global planted area exceeded 90 million hectares for soybean alone by 2018. Benefits include flexibility of post-emergence weed control and enablement of no-till preserving soil moisture and reducing erosion. Concerns about herbicide over-reliance led to development of stacked herbicide tolerance with dicamba and

Ref: Dill GM Crops 2005 Roundup Ready; Funke PNAS 2006 CP4; NCBI NBK131103; ISAAA Pocket K 10 herbicide tolerance mechanism.

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