New Restriction Fragment Length Polymorphisms in the Cytochrome Oxidase I Gene Facilitate Host Strain Identification of Fall Armyworm (Lepidoptera: Noctuidae) Populations in the Southeastern United States

Abstract

Several restriction sites in the cytochrome oxidase I gene of fall armyworm, Spodoptera frugiperda (J.E. Smith), were identified by sequence analysis as potentially being specific to one of the two host strains. Strain specificity was demonstrated for populations in Florida, Texas, Mississippi, Georgia, and North Carolina, with an AciI and SacI site specific to the rice (Oryjza spp.)-strain and a BsmI and HinfI site joining an already characterized MspI site as diagnostic of the corn (Zea mays L.)-strain. All four of these sites can be detected by digestion of a single 568-bp polymerase chain reaction-amplified fragment, but the use of two enzymes in separate digests was found to provide accurate and rapid determination of strain identity. The effectiveness of this method was demonstrated by the analysis of almost 200 adult and larval specimens from the Mississippi delta region. The results indicated that the corn-strain is likely to be the primary strain infesting cotton (Gossypium spp.) and that an unexpected outbreak of fall armyworm on the ornamental tree Paulownia tomentosa (Thunb.) Sieb. & Zucc. ex Steud. was due almost entirely to the rice-strain.

Maize toxin degrades peritrophic matrix proteins and stimulates compensatory transcriptome responses in fall armyworm midgut

“…Midguts were dissected from larvae 2 d after molting to the last instar with masses between 300 and 400 mg. A piece of the abdominal body cavity was used to determine that all larvae used for RNA-seq had the RFLP marker associated with the corn strain (Levy et al, 2002;Nagoshi et al, 2006).…”

Genetic Characterization of Fall Armyworm (Lepidoptera: Noctuidae) Host Strains in Argentina

“…All 19 Argentina samples clustered with fall armyworm, segregating with the consensus barcodes of one or the other strain. The strain segregation is based on the presence of nine strain-speciÞc, single nucleotide polymorphisms within the 606-bp barcoding segment (Nagoshi et al 2006b. Each Argentine specimen carried the complete set of nucleotides consistent with either the COI-RS or COI-CS haplotypes (Table 2), providing evidence that the genetic markers indicative of fall armyworm host strains are intact in Argentine populations.…”

Methodology Microsatellite markers for genetic studies of the fall armyworm, Spodoptera frugiperda

“…Challenges in these research areas are to understand host-plant adaptation, multi-scale geographic genetic differentiations, and population ecology of sympatric speciation. Basic geographic differentiations and host-range association studies have been performed using allozyme markers (Pashley et al, 1985;Pashley, 1986), random amplified polymorphic DNA and amplified fragment length polymorphism markers (Martinelli et al, 2006(Martinelli et al, , 2007, and mitochondrial cytochrome oxidase subunit I genes (Nagoshi et al, 2006;Nagoshi, 2010). However, the use of highly variable and sensitive molecular markers as microsatellites has not yet been reported in this species in molecular ecology studies.…”