Submitted to: Journal of Insect Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/7/2005
Publication Date: 8/3/2005
Citation: Coates, B.S., Hellmich II, R.L., Lewis, L.C. 2005. Two differentially expressed Ostrinia nubilalis ommochrome-binding protein-like genes (obp1 and obp2) in larval fat body. Journal of Insect Science. 5:19. Interpretive Summary: The European corn borer is a serious insect pest of corn in the United States. Damage and control costs for this insect exceed $1 billion from an annual crop valued at more than $22 billion. In this study, two DNA markers were developed for these moths. These markers constitute two genes that may be involved in survival during winter conditions. These regions could be used to understand how these insects endure harsh environments. Additionally, these DNA markers show differences between individual European corn borers. These DNA markers can be used in studies related to locating genes responsible for other traits via linkage mapping. All stakeholders interested in understanding the genetics of European corn borer and finding novel ways to control this pest will be interested in this research.
Technical Abstract: Ommochrome-binding proteins function in coloration and detoxification pathways by transporting tryptophan metabolites, and increase in hemolymph concentration prior to diapause. Two phylogenetically distinct ommochrome-binding protein genes (obp1 and obp2) were isolated from Ostrinia nubilalis. Sequence alignment identified 21 single nucleotide polymorphisms (SNPs) between obp1 and 23 SNPs between obp2 alleles. PCR-RFLP assays (HinfI and HaeIII) indicated obp1 and obp2 alleles segregate independently in F2 pedigrees constituting two separate loci, and are located in proximity on the same chromosome (< 0.78 cM). RT-PCR detected obp1 and obp2 transcripts in fat body, not midgut or head tissue. The obp1 transcript was observed only in 5th instar fat body, whereas obp2 transcripts were present at 4th and 5th instar stages with fat body level peaking in 5th instar wandering and 1 wk diapaused larvae. Expression pattern of obp1 and obp2 may suggest maintenance of gene duplicates by change in temporal expression. Fat body OBP1 transcript level may increase in response to detoxification requirements when larval metabolic rates increase during fat accumulation prior to diapause.