Host type identification of Spodoptera frugiperda invading in Guangzhou by different molecular markers

Objective  Different molecular markers were used to identify the host types of Spodoptera frugiperda which invaded Guangzhou, in order to monitor the diffusion of insect sources and to offer forecasting and early warning of insect conditions.

Method  The host types of S. frugiperda collected from maize plants in Guangzhou were identified using three COI gene markers (COI-A, COI-B and COI-C) and the Tpi gene marker. The identification results were compared.

Result  Based on sequence alignment and haplotype analysis, S. frugiperda samples invading Guangzhou were identified as the “rice strain” using COI-A,COI-B and COI-C markers. A sample was identified to be the hybrid of S. frugiperda and Mythimna separate using COI-A marker. S. frugiperda samples invading Guangzhou were identified as the “corn strain” using the Tpi gene marker, and the 126th and 127th bp were GA/AT heterozygous.

Conclusion  The COI-A marker has relatively strong ability of species identification as it can identify the hybridization events between S. frugiperda and other close related species. Tpi marker can be used to identify host types of S. frugiperda. Combining the two markers will improve the identification accuracy. The development of microsatellite markers or functional gene markers related to host feeding would enable precise identification of the host types.