Molecular Characterization of Bemisia tabaci Populations Using Mitochondrial COI Gene Sequencing

Abstract

Background: Whiteflies associated with vegetable and cotton crops can be difficult to identify reliably using external morphology because Bemisia tabaci represents a cryptic species complex. Aims: To assess the population dynamics and host association of whitefly populations across vegetable and cotton crops using molecular identification, and to evaluate species dominance to inform targeted integrated pest management (IPM) strategies. Study Design: Cross-sectional molecular diagnostic study. Place and Duration of Study: The study was conducted at Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, during 2025. Methodology: Whitefly specimens were collected from five host crops representing diverse botanical families, namely okra, tomato, cotton, brinjal and cucumber. Genomic DNA was extracted, followed by PCR amplification and sequencing of the mitochondrial cytochrome oxidase subunit I gene. Sequences were analysed using NCBI-BLAST for species identification and submitted to the GenBank database for accession assignment. Results: Molecular diagnosis and sequence alignment confirmed that all whitefly populations collected across all host crops belonged to Bemisia tabaci, showing high sequence homology with GenBank reference entries. Corresponding GenBank accession numbers were assigned to sequences from each host. The consistent identification of B. tabaci across solanaceous, malvaceous and cucurbitaceous crops reflects its high polyphagy and broad host range in the surveyed ecosystem. Conclusion: Bemisia tabaci is the dominant whitefly species infesting vegetable and cotton crops in the region. Rapid gene sequencing serves as an accurate diagnostic tool, though further fine-scale genetic resolution of cryptic biotypes (e.g., MEAM1, MED or Asia groups) is essential for tailoring biotype-specific IPM programmes.