Molecular analysis of gene expression in oat plants that are tolerant or sensitive to barley yellow dwarf viruses infection

Barley yellow dwarf viruses (BYDVs) cause the most economically important and widespread virus disease of small grains. Breeding resistant plants has been the most effective and economical method of control. In order to understand the molecular basis for tolerance to BYDV, studies were initiated to characterize the genes involved in the tolerance.Two dimensional protein gel electrophoresis was used to determine whether there were differences in protein profiles between one sensitive (Clintland 64) and four tolerant oat cultivars (Ogle, IL86-5698, IL86-1156 and IL86-6404). Differences were observed among all tested cultivars, but no single protein was found in all tolerant cultivars that was not also found in the sensitive cultivar. Differences were observed in mRNAs from three oat cultivars (Clintland 64, IL86-5698 and Ogle using differential display of mRNA. Further analysis of recovered polymorphic bands showed no detectable differences in Southern and northern blots from the tested cultivars. Since four different tolerant cultivars were examined, it is possible that different genes were responsible for tolerance in the different tolerant cultivars. To simplify the analysis, subsequent experiments focused on one pair of sensitive (Clintland 64) and tolerant (IL86-5698) oat cultivars.Representational difference analysis (RDA) was adapted to clone the differentially expressed or polymorphic genes from mRNAs in Clintland 64 or IL86-5698. One cDNA clones, OARE (for OAt RetroElement), identified by RDA was similar to copia-like retroelements and another one, OACW (for Oat Cold or Water-like gene), was similar to cold or water stress-related genes. Neither of the clones revealed differences in genomic DNAs from Clintland 64 or IL86-5698. Both were expressed constitutively and OACW expression is at the same levels in roots and leaves. Differences were observed in the PCR products from genomic DNA using a primer designed from the OACW sequence, and Dpn II digested major PCR products.Transcription of retroelements and cold and water stress-related genes has been reported to be activated by environmental stresses. Studies have also shown that symptom development, biochemical changes and root growth after BYDV infection are similar to those induced by environmental stresses. This suggests that the functions of the two clones I have found may be related to plant responses to BYDV infection.U of I OnlyETDs are only available to UIUC Users without author permissio