A comparison of transcripts coding for novel secreted salivary gland proteins in Hessian fly from the United States and Israel

Hessian fly larvae induce the formation of nutritive tissue in susceptible wheat plants to provide a favorable environment for larval development. The mechanism by which larvae manipulate host cells in susceptible wheat to produce the nutritive tissue is not clear. However, it is believed that secreted salivary gland proteins play an important role in the establishment of larval feeding sites in a manner similar to the effector proteins reported for plant pathogens. A number of gene families coding for novel secreted salivary gland proteins have been identified from Hessian fly through an extensive salivary gland EST project, and it is speculated that the encoded proteins are effectors eliciting re-programming of host cells and development of nutritive tissue. Additionally, some of these secreted salivary gland proteins may be the products of avirulence genes. Hessian fly populations from Israel have displayed virulence to a greater range of resistance genes in wheat than has been seen in populations from the United States. In the present study, we have compared the transcripts of gene families coding for novel secreted salivary gland proteins in Hessian flies from the United States and Israel. Differences and commonalities in the transcripts and the proteins they encode are described and discussed.