ECOLOGICALLY-BASED MANAGEMENT OF INSECT PESTS OF CORN, WITH EMPHASIS ON CORN BORERS, ROOTWORMS, AND CUTWORMS
Location: Corn Insects and Crop Genetics Research
Title: Mobilizing the genome of Lepidoptera through novel sequence gains and end creation by non-autonomous Lep1 Helitrons
Submitted to: DNA Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 28, 2011
Publication Date: January 1, 2012
Citation: Coates, B.S., Hellmich II, R.L., Grant, D.M., Abel, C.A. 2012. Mobilizing the genome of Lepidoptera through novel sequence gains and end creation by non-autonomous Lep1 Helitrons. DNA Research. 19(1):11-21.
Interpretive Summary: The European corn borer and several other moth species feed upon and cause damage to crop plants resulting in significant economic loss to producers, growers, and farmers. Populations of these insect pests can change over time as a result of adaptations to their local environment and in response to management practices employed by stakeholders. These adaptations often result in reduced control of insect feeding damage to crop plants. We have discovered a mobile section of deoxyribonucleic acids that move among different positions within the genome of a lepidopteran insect that is capable of inserting within gene coding regions. This mobile deoxyribonucleic acid region is highly conserved within the genomes of crop pest insects, and appears to affect the structure of genes. The consequence of these changes to a gene remains unknown, but is likely to cause a change in function. We developed methods for the identification of this mobile region within genomes of crop pests, which is useful to all scientists interested in the genetics and adaptation of moths and butterflies.
The integration of transposable elements within gene coding regions can affect expression levels and transcript splicing patterns. The repetitive element, Lep1, is comprised of a conserved 134 base pairs (bp) consensus core region among species of Lepidoptera, and was defined as a short intersperse nuclear element based upon structural features including a transfer-ribonucleic acid-derived region, an internal ribonucleic acid polymerase III promoter preceded by a promoter element, and a 3' flanking poly-thymidine termination signal. Lep1 elements also contain an internal microsatellite that was mobilized within transcripts under cell stress conditions, and reintegrated into the genome by reverse transcription. In total, 5541 Lep1 copies were predicted within the silkmoth, Bombyx mori, whole genome assembly, shown to be localized with gene coding regions, and integration into transcribed regions documented through annotation of chimeric expressed sequence tags from species of Lepidoptera. Lep1 short intersperse nuclear elements are actively mobile within genomes and are a source of haplotype variation within gene coding regions, but the impact on gene expression, transcript splicing, or resultant function within species of Lepidoptera remains unknown.