Plasmid

Part:BBa_K5120014

Designed by: Ananya Anuj Dharna   Group: iGEM24_Thailand-RIS   (2024-10-01)

Isoflavanoid Synthase (IFS) in pEAQ DEST 1

Sequence and Features


Assembly Compatibility:
  • 10
    INCOMPATIBLE WITH RFC[10]
    Illegal prefix found in sequence at 10226
    Illegal suffix found in sequence at 1
  • 12
    INCOMPATIBLE WITH RFC[12]
    Illegal EcoRI site found at 10226
    Illegal SpeI site found at 2
    Illegal PstI site found at 16
    Illegal NotI site found at 9
    Illegal NotI site found at 5173
    Illegal NotI site found at 10232
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal EcoRI site found at 10226
    Illegal BglII site found at 644
    Illegal BglII site found at 1657
    Illegal BglII site found at 1913
    Illegal BglII site found at 1933
    Illegal BglII site found at 8791
    Illegal BglII site found at 9775
    Illegal BamHI site found at 1146
    Illegal XhoI site found at 714
  • 23
    INCOMPATIBLE WITH RFC[23]
    Illegal prefix found in sequence at 10226
    Illegal suffix found in sequence at 2
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal prefix found in sequence at 10226
    Illegal XbaI site found at 10241
    Illegal SpeI site found at 2
    Illegal PstI site found at 16
    Illegal NgoMIV site found at 2397
    Illegal NgoMIV site found at 3353
    Illegal NgoMIV site found at 3636
    Illegal NgoMIV site found at 4168
    Illegal NgoMIV site found at 5045
    Illegal NgoMIV site found at 5169
    Illegal NgoMIV site found at 6196
  • 1000
    COMPATIBLE WITH RFC[1000]

Usage and Biology

Figure 1:Vector Diagram for pmIFS in pEAQ DEST 1

pmIFS in the pEAQ DEST 1 plasmid is a genetic construct designed for the expression of Isoflavone Synthase (IFS) in plants like Nicotiana benthamiana. IFS is responsible for converting flavanones into isoflavones, which are important compounds in the biosynthesis of isoflavonoids. This construct is optimized for efficient expression of pmIFS in plant systems, utilizing the pEAQ-HT-DEST1 backbone for high-level transient expression. With its assembly compatibility and regulatory elements, it is a versatile tool for investigating isoflavonoid biosynthesis and metabolic engineering in synthetic bio applications.

Features of pEAQ DEST1 plasmid backbone that made us choose it as our plasmid backbone

  1. Enables transient gene expression in plants
  2. Contains strong CaMV 35S promoter for high-level expression
  3. Is equipped with elements such as the LB and RB T-DNA repeats, which are necessary for T-DNA transfer during Agrobacterium-mediated plant transformation
  4. Suppresses gene silencing via P19 suppressor
  5. Has kanamycin resistance for transformed bacteria and plant selection
  6. Contains NOS terminators/promoters commonly used in plant expression
  7. Is Compatible with gateway in-fusion cloning technology

Proof of Function

To allow for transient (co)expression of isoflavone biosynthetic genes in N. benthamiana, we utilized agrobacterium vector-mediated infiltration (commonly referred to as agro-infiltration) as a method to perform transient transformation.

Figure 2: Primers used for colony PCR

This composite part was first cloned using In-Fusion Cloning where the target gene fused with the plasmid backbone. From then on, the resulting solution (from the combination phase of In-Fusion Cloning) was transformed into Escherichia coli strain DH5-α via the heat shock transformation method. Then the transformed E. coli strain was grown in Kanamycin to verify transformation and transformed E. coli strains were picked through colony PCR. The transformed plasmids in the E. coli strains were introduced to A. tumefaciens where the A. tumefaciens was again grown.

Figure 3: PCR results for composite parts with genes for selected enzymes from the Isoflavonoid biosynthetic pathway

The Polymerase Chain Reaction (PCR) was used to confirm the successful integration of the composite part into the N. benthamiana genome after agroinfiltration. PCR amplifies specific DNA sequences, allowing researchers to detect where the gene of interest can be inserted into the plant's genome. In this case, primers were designed to target the IFS gene in the composite part, and after running the PCR, the amplified product was visualized on an agarose gel. A distinct band corresponding to the expected size of the IFS gene confirmed that the transformation was successful, further supporting the functionality of the pathway and the production of isoflavonoids in the modified plants.

Figure 3: HPLC Chromatogram showing the detection of puerarin, daidzin, genistin, iso-vitexin, daidzien and genistein in transformed Nicotiana benthamiana samples

After transformation, the modified plants were tested for isoflavonoid production using High-Performance Liquid Chromatography (HPLC). The chromatogram shows the amounts of each target isoflavonoid: puerarin, daidzein, and genistein with the first peak, observed at around 16.0 minutes, representing puerarin, followed by a peak at approximately 17.0 minutes, which corresponding to daidzin. Further along, a peak at 22.0 minutes is attributed to genistin. Traces of all three compounds were detected in N. benthamiana, a plant that does not naturally produce any of these because it lacks the enzymes needed to do so. This shows that the composite part did function as intended because if it hadn't then the pathway wouldn't have progressed further and produced these isoflavonoids.

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