The Russian wheat aphid Diuraphis noxia (Kurdjumov) is pest on cereal grains. Aphid characteristics, such as leaf rolling and the development of new biotypes, can make it difficult to treat infested crops with pesticides or biological control agents. Therefore it is desirable to identify new sources of wheat resistance. Research will focus on six candidate EST sequences that are highly expressed on Dnx resistant wheat. The location of the sequences will be verified using deletion line mapping and their role in resistance will be assessed. Virus-induced gene silencing (VIGS) utilizes the plant defense system to silence viruses in inoculated plants. Accumulation of virus RNA in the plant triggers the defense system to silence sequences homologous to the introduced virus. Sequences from the plant can be inserted into the virus and silenced along with the virus. The VIGS method can be used to screen EST sequences from resistant wheat for their role in resistance. In my experiment candidate EST sequences from resistant wheat will be silenced and evaluated for their role in resistance to D. noxia. Resistant plants will be inoculated with Barley streak mosaic virus (BSMV) containing a candidate gene. Controls will include resistant plants inoculated with BSMV without EST sequences and non-inoculated plants. Aphids will then be allowed to feed on the plants to assess changes in resistance. The resistance category antibiosis will be measured as aphid population at the end of the experiment. The poster will discuss work that is in progress.