A method for DNA extraction and molecular identification of Aphids

Area of Science:

• Entomology
• Molecular Biology
• Genetics

Background:

• Aphids are significant invasive pests globally, posing identification challenges due to their small size and subtle morphological differences.
• DNA barcoding, particularly using the mitochondrial cytochrome c oxidase I (mtCOI) gene, is a reliable method for insect identification.
• Efficient DNA isolation is crucial for successful DNA barcoding, especially for small specimens like aphids.

Purpose of the Study:

• To develop and demonstrate a modified CTAB method for maximizing DNA quality and yield from small aphids.
• To establish molecular tools for species-level identification of aphids using DNA barcoding.
• To report the molecular identification of *Aphis gossypii* infecting *Solanum trilobatum*.

Main Methods:

• A modified CTAB DNA extraction protocol was optimized for small aphid specimens.
• Polymerase Chain Reaction (PCR) amplification of the mtCOI gene region was performed on isolated DNA.
• Sequencing of the amplified mtCOI gene and subsequent annotation using NCBI BLAST for species identification.

Main Results:

• The modified CTAB method successfully yielded high-quality and quantity genomic DNA from small aphids.
• PCR amplification and sequencing of the mtCOI gene enabled reliable molecular identification.
• The aphid species was identified as *Aphis gossypii*, representing a new host record for *Solanum trilobatum*.

Conclusions:

• The developed DNA isolation method is effective for small insects, aiding in DNA barcoding.
• Molecular identification using mtCOI gene sequencing provides a robust tool for aphid identification and biodiversity studies.
• This study offers valuable insights for the identification and management of *Aphis gossypii* as a pest.