Meeting Abstract

P3.215  Tuesday, Jan. 6  Dehydrin-Like Proteins in Freeze-Tolerant Larvae of the Goldenrod Gall Fly Eurosta solidaginis PRUITT, N. L.*; ARNOLD, A.; ESPINAL, N. A.; JOO, Y. J.; Colgate University, Hamilton, NY npruitt@mail.colgate.edu

Third instar larvae of the goldenrod gall fly Eurosta solidaginis (Diptera: Tephritidae) from populations in North America change from freeze-susceptible to freeze-tolerant just prior to the onset of winter. While studies have documented the accumulation of carbohydrate cryoprotectants during this transition, protein cryoprotectants common in other freeze-tolerant species are less well established in this insect. Using larvae collected from a population in Madison County, NY, which changes from freeze-susceptible to freeze-tolerant in early October, we found evidence of a protein cryoprotectant in freeze-tolerant larvae and larvae that were in the process of transitioning to freeze tolerance. The putative cryoprotective protein has characteristics similar to dehydrin proteins, previously described only in flowering plants. For example, when the freeze-labile enzyme rabbit lactate dehydrogenase is frozen in the presence of protein from freeze-tolerant or transitional gall fly larvae, up to 80 percent of the enzyme’s activity is preserved. Similar to plant dehydrins, the active gall fly fraction is heat stable and does not bind to a weak anion exchanger. Immunoblots using an antidehydrin antibody specific to the lysine-rich K segment of angiosperm dehydrin showed a positive response to gall fly proteins from transitional and freeze-tolerant larvae, but not to proteins from freeze-susceptible larvae. Based on these Western blots, the estimated molecular weight of the gall fly dehydrin-like protein is 66 kDa.