Host gene expression manipulation by the blueberry stem gall wasp, Hemadas nubilipennis

Sunday, November 13, 2022

3:06 PM – 3:18 PM PT

Location: Vancouver Convention Centre, Meeting Room 215/216

Presenting Author(s)

Ellen O. Martinson

Assistant Professor
University of New Mexico
Albuquerque, New Mexico

Co-Author(s)

Michael Sergeant

Ph.D. Student
Wayne State University
Detroit, Michigan
Glen R. Hood

Assistant Professor
Wayne State University
Detroit, Michigan

The blueberry stem gall wasp (BSGW), Hemadas nubilipennis (Hymenoptera: Pteromalidae), initiates stem galls on native low- and high-bush blueberries (Vaccinium spp.) in North America, however in the last decade it has become a pest of cultivated blueberries, reaching outbreak densities in western Michigan. Currently, the ecological and/or genetic mechanism(s) that facilitated this outbreak are unknown. BSGW initiates gall growth by injecting an egg and venom into an actively growing stem causing shoot growth to immediately terminate, thereby reducing the production of fruit buds and causing significant reductions in crop yield. But not all varieties of blueberries are susceptible to BSGW. In this study, we will report the gene expression changes that BSGW initiates in a highly susceptible strain of cultivated Blueberry, Jersey. We have tacked changes in the plant tissue starting at oviposition through mature gall development and compared them to normally developing tissues of the blueberry plant. We have additionally sequenced the venom glands and actively chewing larvae of the BSGW to help determine potential effector molecules that the insect uses to communicate with its host plant. We have directly compared the results of this study to a previous study that sequenced the same time points in the cynipid wasp, Dryocosmus quercuspalustris. By directly comparing the two gallers, we can provide insights in the evolution of galling, as BSGW has recently transitioned from a parasitoid to plant galler in the family Pteromalidae, whereas D. quercuspalustris is part of a superfamily with deep roots in galling.