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Enhanced grain yield potential and Glufosinate-ammonium resistant
Pioneer Hi-Bred International Inc.
7100 NW 62nd Avenue
PO Box 1000
United States of America, 50131
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.
- Agrobacterium-mediated DNA transfer
MADS-box transcription factor zmm28
Proteinase inhibitor II gene terminator
Ubiquitin gene promoter
Ubiquitin 5' Untranslated Region
Phosphinothricin N-acetyltransferase gene
Proteinase inhibitor II gene terminator
The modified maize contains two gene cassettes: Zea mays
MADS-box transcription factor zmm28 and Streptomyces
viridochromogenes phosphinothricin N-acetyltransferase
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
- 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
- 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
- Changes in physiology and/or production
- Resistance to herbicides
- Increased photosynthetic capacity
- Increased nitrogen assimilation
MADS-box transcription factor zmm28 - Zea mays - Maize, Corn, MAIZE
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
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).