DP-2Ø2216-6 - Enhanced grain yield potential and Glufosinate-ammonium resistant maize | BCH-LMO-SCBD-115791 | Living Modified Organism | Biosafety Clearing-House


Living Modified Organism (LMO)

Decisions on the LMO Risk Assessments  
last updated: 25 Nov 2020
Living Modified Organism identity
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Enhanced grain yield potential and Glufosinate-ammonium resistant maize
The maize (Zea mays) has been modified for increased yield and herbicide tolerance. To obtain increased yield, the maize constitutively expresses Z. mays MADS-box transcriptional factor zmm28. Constitutive expression of zmm28 is thought to increase yield by up-regulating genes involved in photosynthesis, nitrogen assimilation and carbon metabolic processes. ZMM28 may also interact with receptors to modulate phytohormone (auxin and gibberellin) signaling. Agronomically, the plants also have greater vegetative stage plant height, leaf biomass and total leaf area. For glufosinate tolerance, the maize expresses Streptomyces viridochromogenes phosphinothricin acetyltransferase, which inactives glufosinate via acetylation.
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.
Characteristics of the modification process
  • Agrobacterium-mediated DNA transfer
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
Gene expression:
The modified maize contains two gene cassettes: Zea mays MADS-box transcription factor zmm28 and Streptomyces viridochromogenes phosphinothricin N-acetyltransferase (pat).

Transcription of zmm28 is under control of the Z. mays gos2 promoter and the Solanum tuberosum proteinase inhibitor II gene (pinII) terminator. In addition to the zmm28 coding sequence, a Z. mays ubiquitin 1 intron is present at the 5' end of the transcript to enhance gene expression. The gos2 promoter is expected to promote constitutive expression in all plant tissues.

Transcription of pat is under control of the Z. mays ubiquitin promoter and the pinII terminator. In addition to the pat coding sequence, the Z. mays ubiquitin 1 5' untranslated region and intron were added to the 5' end to enhance gene expression. The ubiquitin promoter is expected to promote high levels of constitutive expression in all plant tissues.

- The sequence of zmm28 is comprised of the 5’ UTR at bp 2,749-2,808 (60 bp long), coding sequence at bp 2,809-3,564 (756 bp long) and the 3’ UTR at bp 3,565-3,605 (41 bp long).
- The pat coding sequence was optimized for expression in maize.
- Southern-by-Sequencing analysis indicted that the DP202216 line contained a single T-DNA insertion containing the two gene cassettes without any rearrangements or integration of the vector backbone.
LMO characteristics
  • BCH-GENE-SCBD-115790-1 MADS-box transcription factor zmm28 | Zea mays (Maize, Corn, MAIZE)
    Protein coding sequence | Changes in physiology and/or production (Yield)
The maize expresses both the introduced and native zmm28. In wild-type plants, zmm28 is expressed in the leaf, root, stem, shoot apical meristem tassel, and ear. However, the transcript and protein are undetectable until V6 (6 fully expanded leaves) in leaves and peak at V11. The gos2 promoter confers constitutive expression of the introduced zmm28 coding sequence throughout the the plant tissues and life stages.

Transcriptomic analysis of DP202216 maize indicated that the extended expression of zmm28 caused 192 up-regulated
and 64 down-regulated genes in comparison to the wild-type. Some genes with increased transcription were related to photosynthesis, carbohydrate metabolic processes and nitrogen assimilation. A summary of the transcriptomic data can be found in the attached publication (see Wu et al. (2020) Overexpression of zmm28 increases maize grain yield in the field, PNAS).
  • Food
  • Feed
Detection method(s)