PH-ØØØ676-7 - Male-sterile, herbicide-tolerant maize | BCH-LMO-SCBD-14791 | Living Modified Organism | Biosafety Clearing-House

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Living Modified Organism (LMO)
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Decisions on the LMO Risk Assessments  
published: 05 Jun 2006 last updated: 14 Sep 2012
Living Modified Organism identity
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Male-sterile, herbicide-tolerant maize
EN
676
Yes
PH-ØØØ676-7
The maize lines 676, 678, and 680 were genetically engineered to express male sterility and tolerance to glufosinate ammonium, the active ingredient in phosphinothricin herbicides (Basta®, Rely®, Finale®, and Liberty®).

The male-sterile trait was introduced by inserting a bacterial gene encoding the enzyme DNA adenine methylase (DAM). Expression of the Escherichia coli dam gene in specific plant tissues results in the inability of the transformed plants to produce anthers or pollen, resulting in a male-sterile plant. The PAT enzyme was used as a selectable marker enabling identification of transformed plants during tissue culture regeneration, and as a field selection method to identify the male-sterile lines prior to flowering. Under field conditions, plants that were not male-sterile could be eliminated by application of the herbicide glufosinate ammonium. The novel hybrid system provided an efficient and effective way to identify male-sterile plants for use in hybrid seed production.
EN
The term “Recipient organism” refers to an organism (either already modified or non-modified) that was subjected to genetic modification, whereas “Parental organisms” refers to those that were involved in cross breeding or cell fusion.
EN
  • PH-ØØØ678-9 - Male-sterile, herbicide-tolerant maize
    | Pioneer Hi-Bred International Inc. | Changes in physiology and/or production (Reproduction, Male sterility), Resistance to herbicides (Glufosinate)
  • PH-ØØØ68Ø-2 - Male-sterile, herbicide-tolerant maize
    | Pioneer Hi-Bred International Inc. | Changes in physiology and/or production (Reproduction, Male sterility), Resistance to herbicides (Glufosinate)
Characteristics of the modification process
PHP6710
EN
  • Agrobacterium-mediated DNA transfer
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
  • BCH-GENE-SCBD-15002-4 Phosphinothricin N-acetyltransferase gene | Streptomyces viridochromogenes (STRVR)
    Protein coding sequence | Resistance to herbicides (Glufosinate)
  • BCH-GENE-SCBD-15008-3 DNA Adenine Methylase gene | Escherichia coli (ECOLX)
    Protein coding sequence | Changes in physiology and/or production (Reproduction, Male sterility)
  • BCH-GENE-SCBD-103911-3 5126 anther-specific promoter | Zea mays (Maize, Corn, MAIZE)
    Promoter
  • BCH-GENE-SCBD-100367-4 Proteinase inhibitor II gene terminator | Solanum tuberosum (Potato, SOLTU)
    Terminator
  • BCH-GENE-SCBD-100287-7 CaMV 35S promoter | Cauliflower mosaic virus (CaMV)
    Promoter
  • BCH-GENE-SCBD-100290-6 CaMV 35S terminator | Cauliflower mosaic virus (CaMV)
    Terminator
Both genes are inserted as a single copy locus in the genome. A partial copy of the pat gene insertion was also detected at another locus in the genome.
EN
LMO characteristics
EN
  • Feed
Detection method(s)
EN
Additional Information
Glufosinate tolerance in these maize lines is the result of introducing a gene encoding the enzyme phosphinothricin-N-acetyltransferase (PAT) isolated from the common aerobic soil actinomycete, Streptomyces viridochromogenes, the same organism from which glufosinate was originally isolated. The PAT enzyme catalyzes the acetylation of phosphinothricin, detoxifying it into an inactive compound. The PAT enzyme is not known to have any toxic properties.

Glufosinate chemically resembles the amino acid glutamate and acts to inhibit an enzyme, called glutamine synthetase, which is involved in the synthesis of glutamine. Essentially, glufosinate acts enough like glutamate, the molecule used by glutamine synthetase to make glutamine, that it blocks the enzyme's usual activity. Glutamine synthetase is also involved in ammonia detoxification. The action of glufosinate results in reduced glutamine levels and a corresponding increase in concentrations of ammonia in plant tissues, leading to cell membrane disruption and cessation of photosynthesis resulting in plant withering and death.
EN
Records referencing this document Show in search
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Country's Decision or any other Communication Living modified organism(s) 1
Risk Assessment generated by a regulatory process Living modified organism(s) 2
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