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Living Modified Organism (LMO)
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Decisions on the LMO Risk Assessments  
last updated: 13 Feb 2025
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.
Short-stature maize
EN
MON94804
Yes
MON-948Ø4-4
The maize (Zea mays) was modified to have a short stature to reduced lodging and breakage in the field. The changed architecture (reduced internode length) was achieved by preventing the biosynthesis of bioactive gibberellins through the silencing of gibberellic acid 20 oxidase 3 and 5 in vegetative tissues. To achieve this gene silencing, the maize expresses a microRNA suppression cassette, which triggers an RNA interference response within its cells and prevents the translation of these two proteins. The silencing of gibberellic acid 20 oxidase 3 and 5 is restricted to the vegetative tissues to not interfere with the sex determination in maize flowers. In addition, the modified maize is also considered to be "marker-free" since the selection cassette was removed during development of the maize. 
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.
Maize line HCL301
EN
Characteristics of the modification process
PV-ZMAP527892
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 maize expresses a microRNA interference cassette. Transcription of the this gene cassette is under control of the Rice tungro bacilliform virus 1 promoter and a synthetic maize terminator (GST43). The initial transcript includes both a maize heat shock protein 70 intron to enhance transcription and a gibberellic acid 20 oxidase suppression sequence, comprised of two inverted repeats of gibberellic acid 20 oxidase flanked and separated by Oryza sativa precursor miRNA MIR1425 sequences. Upon transcription, the inverted sequences base pair to form a hairpin structure (pri-miRNA), which will trigger an RNA interference response in the cells, resulting in processing of the pri-miRNA into mature microRNA. Thus, no translation of this coding sequence is expected to occur. For more information, see the section "Please describe how the expression of the gene(s) was affected" below.

Note:
  • Elevated levels of transcription is expected in vegetative tissues due to the nature of the promoter and the heat shock protein 70 intron.
  • Next-generation sequencing analysis indicated that a single T-DNA insertion into the maize genome occurred and the gibberellic acid 20 oxidase suppression cassette was intact without rearrangements. However, the right border was absent in the insertion, while the left border was truncated. The analysis also indicated that the T-DNA insertion resulted in a 41 basepair deletion within the host genome surrounding the T-DNA insertion site.
  • The initial T-DNA insertion contained a selectable marker cassette (Oryza sativa actin 1 promoter, O. sativa actin 1 intron, Arabidopsis thaliana chloroplast transit peptide 2, Agrobacterium tumefaciens 5-enolpyruvylshikimate-3-phosphate and A. tumefaciens nopaline synthase terminator), which was excised using loxP recombination during development by crossing with a Cre recombinase expressing maize line. Sequencing analysis confirmed that the selectable marker cassette and the Cre-recombinase from vector PV-ZMOO513642 were both absent.
EN
LMO characteristics
After transcription, the nascent transcript contains two inverted repeats of gibberellic acid 20 oxidase flanked and separated by Oryza sativa precursor miRNA MIR1425 sequences. The inverted sequences will then base pair to form a hairpin structure (pri-miRNA), which is then processed into a duplex pre-miRNA by DICER LIKE 1. Following this, a mature 21-nucleotide miRNA complexes with ARGONAUTE proteins and the miRNA duplex is unwound, leaving a singular strand of miRNA within the protein. The activated complex (the RNA-induced silencing complex) then acts as a sequence-specific endonuclease, directing the cleavage of messenger RNA with complementarity to the miRNA. Due to the homology to both gibberellic acid 20 oxidase 3 and 5, the host cell targets the endogenous expression of these two genes, preventing their expression and thus the biosynthesis of bioactive gibberellins.

Note:
  • The gibberellic acid 20 oxidase suppression sequences share a 100% homology with the gibberellic acid 20 oxidase 3 sequence and a 1-nucleotide mismatch to the gibberellic acid 20 oxidase 5 sequence. The one base mismatch does not impact the silencing of the gibberellic acid 20 oxidase 5.
  • For more information regarding miRNA in plants, kindly refer to Xu and Chen (2023) and/or Mencia and others (2022).
EN
  • Feed
  • Food
Additional Information
Other names for this LMO include: GA20ox_SUP maize and semi-dwarf maize.

According to the developer, the reduced plant height may also allow for increased flexibility to implement more timely and precise crop input applications with standard ground equipment. As maize plants grow, access to fields planted with typical height maize becomes limited when the plants grow taller than a standard ground sprayer boom height. Thus, a reduced height in maize plants could potentially eliminate the need for aerial application and/or avoid early season applications that may not be needed otherwise.
EN
Records referencing this document Show in search
Record type Field Record(s)
Country's Decision or any other Communication LMO identification 3
Risk Assessment generated by a regulatory process Living modified organism(s) 3
Living Modified Organism Recipient Organism or Parental Organisms 1

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