ACS-OSØØ2-5 - Liberty Link™ rice | BCH-LMO-SCBD-14859 | Living Modified Organism | Biosafety Clearing-House

BCH-LMO-SCBD-14859-7   |   PDF   |   Print   |  

Living Modified Organism (LMO)

Decisions on the LMO Risk Assessments  
published: 05 Jun 2006 last updated: 06 May 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.
Liberty Link™ rice
Rice resistant to the herbicide glufosinate through introduction of the bar gene from Streptomyces hygroscopicus which encodes the enzyme phosphinothricin-N-acetyltransferase (PAT) that catalyzes the acetylation of phosphinothricin (glufosinate), detoxifying it into an inactive compound.
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.
Variety: Bengal
Characteristics of the modification process
  • Direct DNA transfer
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
The phosphinothricin-N-acetyltransferase enzyme coding sequence was obtained from the Streptomyces hygroscopicus HP632 strain. the The N-terminal codon of the wild type gene was modified to and ATG.

Southern blot analysis indicated that one intact copy of the transformation cassette integrated into the host genome. No portions of the vector backbone were detected in the LMO
LMO characteristics
  • Food
Additional Information
Rice line LLRICE62 was genetically engineered to express 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 these rice lines is the result of introducing a gene encoding the enzyme phosphinothricin-N-acetyltransferase (PAT) isolated from the common aerobic soil actinomycete, Streptomyces hygroscopicus, 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. The PAT encoding gene (bar) was introduced into the rice genome by direct gene delivery transformation, and the resulting rice lines displayed field tolerance to phosphinothricin-containing herbicides.