Submitted to: Genbank
Publication Type: Other
Publication Acceptance Date: 8/8/2002
Publication Date: 1/9/2004
Citation: Roehrdanz, R.L., Szalanski, A.L., Levine, E. 2004. Mitochondrial DNA and ITS1 differentiation in geographical populations of northern corn rootworm, Diabrotica barberi (Coleoptera: Chrysomelidae): Identification of distinct genetic populations. Genbank. Accession Nos. AF155574 and AY136647-AY136664.
Technical Abstract: Genetic variation of mitochondrial DNA (mtDNA) and the nuclear ribosomal spacer, ITS1, in local and dispersed geographical populations of northern corn rootworm, Diabrotica barberi Smith and Lawrence was examined. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for mtDNA and DNA sequencing plus PCR-RFLP analysis was used for ITS1. Insects were collected from 66 locations in 10 states ranging from PA to KS and ND. Sequencing of the 645-646 bp ITS1 amplicon from 19 individual beetles revealed two polymorphic sites, one of which altered a restriction site for the restriction enzyme Bcl I. PCR-RFLP analysis of insects from 38 sample sites with Bcl I detected three genotypes. Many beetles had heterogeneity at the nucleotide site recognized by Bcl I, which was supported by DNA sequence data. Populations east of IL were homogeneous for one genotype, two genotypes were observed in IL, WI and ND, while SD, NE, IA, and KS populations were composed of all three genotypes. There appears to be a phylogeographic pattern of ITS1 genetic diversity. The mtDNA had 58 haplotypes that displayed a strong east-west geographical partition. The region of overlap occurred in a few counties of east-central IL. Populations to the east had less variability (9 haplotypes) than those to the west (46 haplotypes). The remaining haplotypes were recovered only in the boundary zone. Trees based on genetic distance measurements of the mtDNA produced two distinct clades. One clade contained all the eastern haplotypes along with a group of haplotypes from the northern Great Plains. The other clade included the remaining western haplotypes. Possible reasons for this population structure including expansion from different glacial relicts, historic host plant differences, and endosymbiont driven reproductive incompatibilities are discussed. Observed genetic demarcation is relevant given regional differences in the occurrence of multi-year diapause and the impending release of Bt genetically modified corn developed for the control of corn rootworms. GenBank accessions for Diabrotica barberi ITS1 sequences: AY136647 AY136648 AY136649 AY136650 AY136651 AY136652 AY136653 AY136654 AY136655 AY136656 AY136657 AY136658 AY136659 AY136660 AY136661 AY136662 AY136663 AY136664 AF155574