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Cantaloupe B (delayed ripening)
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
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
Neomycin Phosphotransferase II - Escherichia coli - ECOLX
Resistance to antibiotics - Kanamycin
S-adenosylmethionine hydrolase gene - Bacteriophage T3 - Phage T3, T3
Changes in physiology and/or production - Ripening
Canteloupe with delayed ripening due to expression of the SAMase
gene from Escherichia coli bacteriophage T3.
- Changes in physiology and/or production
- Resistance to antibiotics
The A and B lines of cantaloupe (Cucumis melo) were developed
through a specific genetic modification to express a reduced
accumulation of S-adenosylmethionine (SAM) and consequently the
trait of delayed ripening. This was accomplished by the
introduction of a bacteriophage encoded enzyme,
S-adenosylmethionine hydrolase, capable of degrading and thus
reducing SAM. The conversion of SAM to
1-aminocyclopropane-1-carboxylic acid (ACC) is the first step in
ethylene biosynthesis and the lack of sufficient pools of SAM
results in significantly reduced synthesis of this phytohormone,
which is known to play a key role in fruit ripening.
These lines were created by Agrobacterium-mediated transformation
in which the transfer-DNA (T-DNA) contained the
S-adenosylmethionine hydrolase encoding SAMase gene from
Escherichia coli bacteriophage T3. The constitutive expression of
the SAMase gene was controlled by inclusion of regulatory DNA
sequences from A. tumefaciens. In addition, the T-DNA contained
sequences encoding the enzyme neomycin phosphotransferase II
(NPTII) from the Tn5 transposon of Escherichia coli, strain K12,
under the control of the nos promoter from A. tumefaciens. The
expression of NPTII activity was used as a selectable trait to
screen transformed plants for the presence of the SAMase gene.