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Modified Organism
Poplar with modified lignin
Record information and status
Record ID
115134
Status
Published
Date of creation
2019-08-21 20:09 UTC (austein.mcloughlin@cbd.int)
Date of publication
2019-08-21 20:09 UTC (austein.mcloughlin@cbd.int)

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.

LMO name
Poplar with modified lignin
Transformation event
pHG8-CAD4
Developer(s)
Prof.dr. Wout Boerjan
Departement Plantensysteembiologie
VIB-UGent
Technologiepark 927
Gent
Belgium, B-9052
Phone:+32 9 331 38 81
Email:wout.boerjan@psb.vib-ugent.be
Url:Wout Boerjan Lab
Description
The genetically modified trees have an altered lignin composition resulting from the downregulation of the cinnamyl alcohol dehydrogenase (CAD) enzyme through RNA interference. CAD catalyzes the last step in the monolignol synthesis. The remaining CAD activity in the modified trees is about 15% of that in wildtype trees. The altered lignin composition has a positive effect on the ease with which the lignin can be broken down to gain access to the valuable sugar content in the cellulose and hemicellulose in the wood of the trees. A lowered CAD activity has been found to naturally occur in the U.S. in loblolly pine (Pinus taeda) and in wild black poplar in Europe with comparable effects on the wood composition.

The modified trees also carry the NPT-II selection marker gene allowing an easy selection of transformed plants using kanamycin.
Recipient Organism or Parental Organisms
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.
Populus tremula x Populus alba - Gray Poplar
Characteristics of the transformation process
Vector
pHellsgate8
Techniques used for the modification
  • Agrobacterium-mediated DNA transfer
Genetic elements construct
 
CaMV 35S promoter
0.35 Kb
 
 
Cinnamyl alcohol dehydrogenase
1.02 Kb
 
 
Pyruvate orthophosphate dikinase, Intron 3
0.77 Kb
 
 
Cinnamyl alcohol dehydrogenase
1.02 Kb
 
 
Octopine Synthase Gene Terminator
0.71 Kb
 
 
Nopaline Synthase Gene Promoter
0.18 Kb
 
 
Neomycin Phosphotransferase II
0.82 Kb
 
 
Nopaline Synthase Gene Terminator
0.25 Kb
 
Further details
Notes regarding the genetic elements introduced or modified in this LMO
RNA interference cassette:
Transcription of the hairpin RNA (HpRNA) is under control of the Cauliflower Mosaic Virus (CaMV) 35S promoter and the Agrobacterium tumefaciens octopine synthase terminator. The transcript is expected to contain an inverted repeat of the Populus tremula x Populus alba cinnamyl alcohol dehydrogenase (CAD) gene separated by a segment sourced from Flaveria trinervia pyruvate orthophosphate dikinase intron 3, which is essential to form a loop that allows the inverted repeats to base pair and form the RNA secondary structure after transcription. Then the hpRNA is sufficient to trigger an RNAi response. Due to the RNAi response, the hpRNA is processed into small interfering RNA (siRNA) and thus no translation to protein is expected to occur.

Selectable marker:
The pHellsgate8 vector also contains a selectable marker for kanamycin resistance. The Escherichia coli neomycin phosphotransferase II gene is under transcriptional control of the A. tumefaciens nopaline synthase promoter and terminator.
LMO characteristics
Modified traits
  • Selectable marker genes and reporter genes
Other gene(s) whose expression was affected by the transformation
Cinnamyl alcohol dehydrogenase - Populus tremula x Populus alba - Gray Poplar
How the expression of the gene(s) was affected
Post-transcription, the inverted repeat segments of the poplar cinnamyl alcohol dehydrogenase (CAD) basepair to form a double stranded region separated a loop derived from the Flaveria trinervia pyruvate orthophosphate dikinase intron 3. The double strandedness of the hpRNA is recognized by host cell RNA interference machinery; DICER processes the hpRNA into siRNA molecules (21-24 base pairs in length), which then associate with ARGONAUTE to form the RISC complex. The siRNA are then used to guide host machinery to degrade transcripts with sequence homology. Thus, the host machinery targets the endogenous CAD transcripts, resulting in silencing of CAD gene expression.
Common use(s)
  • Research
  • Timber
  • Fiber / Textile
Additional Information
Additional Information
Three lines have been created with the same genetics: pHG8-CAD4, pHG8-CAD19 and pHG8-CAD24. Thus, the transformation event listed above represents a placeholder and will be updated should more information become available.