Development of a species diagnostic molecular tool for an invasive pest, Mythimna loreyi using LAMP

The Mythimna loreyi (Duponchel) is one of the well-known a noctuid pest in Africa, Australia, and many Asian countries. This species has recently emerged as an invasive pest of some cereal crops in Korea. However, it is extremely difficult to identify the morphologically similar species, Mythimna separate, which occur at the cornfield in the larvae stage. Therefore, it is hard to accurately investigate invasive pests. In this study, the LAMP assay was developed for rapid, simple, effective species identification. By analyzing the mt genome, the species-specific sequence was found at the coding region of the NADH dehydrogenase subunit 5 gene. Based on this unique sequence, four LAMP primers and two loop primers were designed. The F3 and B3 primers were able to diagnose species-specific in general and multiplex PCR, and specifically reacted within the inner primers in LAMP assay. The optimal incubation condition of the LAMP assay was 61 {square} for 60 minutes with four LAMP primers, though additional loop primer, BF and LF, did not significantly shorten the amplification time. The broad range of DNA concentration was workable in LAMP assay, in which the minimum detectable DNA concentration was 100 pg. Here, DNA releasing method was applied which took five minutes of incubation at 95 {square} without the DNA extraction process, and only some pieces of tissue from larvae and adult samples were needed. The incidence of invasive pests is gradually diversifying, therefore, this simple and accurate LAMP assay possibly applied in the intensive field monitoring for the invasive pests and integrated management of Mythimna loreyi.