SPS-ØØE56-7 - Low acrylamide potential, reduced browning Russet potato | BCH-LMO-SCBD-260756 | Living Modified Organism | Biosafety Clearing-House

Loading...
  |  

Living Modified Organism (LMO)

Decisions on the LMO Risk Assessments  
last updated: 21 Jun 2022
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.
Low acrylamide potential, reduced browning Russet potato
EN
E56
SPS-ØØE56-7
  • - Organization: J.R. Simplot Company () | BCH-CON-SCBD-106427-1
    Organization
    J.R. Simplot Company ()
    Private sector (business and industry)
    5369 West Irving Street
    Boise, ID
    83706, United States of America
    Phone: +1 (208) 780-6066,
    Fax:
    Email:
    Website:
The potato (Solanum tuberosum) was modified to express RNA interference cassettes to reduce enzymatic browning and lower the acrylamide potential. To reduce black spot (or enzymatic browning) due to damage from harvesting and transport, polyphenol oxidase-5 was silenced. To lower the acrylamide potential, asparagine synthetase (reduced free asparagine), water dikinase (lower levels of reducing sugars) and phosphorylase-L (lower levels of reducing sugars) were silenced. Thus, when baked or fried, it is expected that less free asparagine and reducing sugars will react (via the Millard reaction) to form acrylamide. Silencing is not expected to change the levels of essential amino acids or other nutrients in the potato.
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.
Russet Burbank
EN
Characteristics of the modification process
pSIM1278
EN
  • Agrobacterium-mediated DNA transfer
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
The modified potato contains two types of RNA interference cassettes:

  1. The first RNA interference cassette suppresses expression of asparagine synthetase-1 (asn1 from Solanum tuberosum) and polyphenol oxidase 5 (ppo5 from Solanum verrucosum). Transcription of the cassette occurs from two converging promoters: S. tuberosum ADP glucose pyrophosphorylase and  granule-bound starch synthase (convergent orientation). The transcription contains inverted repeats of fragments of asn1 and ppo5, separated by a spacer region.
  2. The second RNA interference cassette suppresses expression of phosphorylase-L promoter (PhL from S. tuberosum) and alpha-glucan water dikinase R1 gene promoter (P-R1 from S. tuberosum). Transcription of the cassette occurs from two converging promoters: S. tuberosum ADP glucose pyrophosphorylase and  granule-bound starch synthase (convergent orientation). The transcription contains inverted repeats of fragments of P-R1 and PhL, separated by a spacer region.

Due to complex rearrangements which occurred during the insertion of the T-DNA, the genome contains two tandem repeats of asn1/P-po5 silencing cassettes (three in total) and three partial tandem repeats of the PhL/R1 silencing cassette in addition to the expected insert containing the two RNAi cassettes. 

After transcription of both cassettes, the transcripts will base-pair with the complementary sequences and form double-stranded structures (hairpin RNA), which will trigger an RNA interference response. Thus, no proteins are expected to be translated from either of these cassettes. See "Other gene(s) whose expression was affected by the transformation" section below.

Note:
  • South blot hybridization indicated that a single integrate of the plasmid occurred in the potato genome without the integration of plasmid backbone sequences. 
  • It is likely that the T-DNA was inserted into chromosome 2.
  • On the 5' end, the left border was deleted and a 35 basepair truncation of the ADP glucose pyrophosphorylase gene promoter occurred.
  • On the 3' end, the right borders were truncated.
  • For more information on the transformation vector, kindly refer to the links in the "Additional information" section below.

Expected sizes for genetic elements (as per pSIM1278 vector):
  • Cassette 1:
    •  ADP glucose pyrophosphorylase gene promoter - 2260 basepairs (bp)
    • asn1 - 405 bp
    • ppo5 - 144 bp
    • Spacer-1 - 157 bp
    • asn1 - 406 bp
    • Granule bound starch synthase gene promoter - 686 bp
  • Cassette 2:
    • ADP glucose pyrophosphorylase gene promote - 2260 bp
    • PhL - 509 bp
    • R1 - 532 bp
    • Spacer-2 - 258 bp
    • Granule bound starch synthase gene promoter - 924 bp
EN
LMO characteristics
After transcription from either of the convergent promoters, the nascent mRNA will fold on itself due to complementary base-pairing between the inverted repeat sequences and form a double-stranded structure (hairpin RNA; hpRNA). The double-stranded structure of the hpRNA will trigger an RNA interference response. Dicer-like proteins will complex with the hpRNA, processing it into small interfering RNA (siRNA), roughly 21 to 23 bp in length. After associating with Agronaute family proteins, mRNA transcripts with sequences complementary to the siRNA will targeted for degradation. Thus, the expression of the endogenous asparagine synthetase, polyphenol oxidase, phosphorylase-L and water dikinase will be silenced.
EN
  • Food
Detection method(s)
EN
Records referencing this document Show in search
Record type Field Record(s)