ACS-ZMØØ5-4 - InVigor™ maize | BCH-LMO-SCBD-14863 | Living Modified Organism | Biosafety Clearing-House


Living Modified Organism (LMO)

Decisions on the LMO Risk Assessments  
published: 05 Jun 2006 last updated: 16 Jul 2013
Living Modified Organism identity
The image below identifies the LMO through its unique identifier, trade name and a link to this page of the BCH. Click on it to download a larger image on your computer. For help on how to use it go to the LMO quick-links page.
InVigor™ maize
The maize line MS6 was genetically engineered to exhibit male sterility, by inserting the barnase ribonuclease gene under the tapetum specific promoter CA55 which results in the destruction of the tapetum and the plant being unable to produce viable pollen.

Tolerance to glufosinate ammonium, the active ingredient in phosphinothricin-based herbicides, was conferred by introducing the bar gene encoding the enzyme phosphinothricin-N-acetyltransferase (PAT).
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.
Corn line: H99
  • ACS-ZMØØ1-9 - InVigor™ maize
    | Bayer CropScience | Changes in physiology and/or production (Reproduction, Male sterility), Resistance to antibiotics (Ampicillin, Chloramphenicol), Resistance to herbicides (Glufosinate)
Characteristics of the modification process
  • Biolistic / Particle gun
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
The transformation of MS6 was done with a plasmid pVE136 containing two chimeric gene constructs: P-CA55 – barnase – T-nos (conferring male sterility) and P-35S – bar – T-nos (conferring tolerance to glufosinate herbicides. pVE136 also contains an origin of replication of the plasmid in Escherichia coli, and the beta-lactamase (bla) gene which confers resistance to the antibiotic ampicilin. The vector was linearized with HindIII prior to transformation.

Results indicate that one copy of the P-CA55 - barnase - T-nos cassette, and two copies (complete and/or partial) of the P-35S – bar – T-nos were integrated.
LMO characteristics
  • Food
  • Feed
  • Biofuel
Detection method(s)
Additional Information
Maize line MS6 was genetically engineered to express male sterility and tolerance to glufosinate ammonium, the active ingredient in phosphinothricin herbicides (Basta®, Rely®, Finale®, and Liberty®). 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.

Glufosinate tolerance in this maize line is the result of introducing a gene encoding the enzyme phosphinothricin-N-acetyltransferase (PAT) isolated from the common aerobic soil actinomycete, Streptomyces hygroscopicus. 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.

The male-sterile trait was introduced by inserting the barnase gene, isolated from Bacillus amyloliquefaciens, a common soil bacterium that is frequently used as a source for industrial enzymes. The barnase gene encodes for a ribonuclease enzyme (RNAse) that is expressed only in the tapetum cells of the pollen sac during anther development. The RNAse affects RNA production, disrupting normal cell functioning and arresting early anther development, thus leading to male sterility. 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.