Comparative transcriptome reprogramming in oak galls containing sexual or asexual generations of parasitoid wasps

Oak galls form when gall wasps lay their eggs into part of the tree; in some galls, this attachment point to the host consists of only a few cells. The gall itself comprises entirely of host tissue; however, the initiation, development, and physical appearance are controlled by the inducer. This raises the intriguing question of the molecular mechanisms underlying gall formation, by which one or a small number of cells are reprogrammed and commit to a novel developmental path. Gall wasps undergo two generations each year, and the galls formed by these two generations exhibit markedly different appearances. We sequenced the transcriptomes of both the sexual and asexual generations of Neuropterus quercusbaccarum and Neuroterus numismalis. The transcriptomes of the generations that occur at the same time of year are more similar to each other than they are to the opposite generation of their respective species. To understand the transcriptional differences between galls that appear in similar ecological niches and galls created by different generations of the same species were sequenced. The sexual generation galls are blister and currant and the asexual generation galls are button and spabgle from the two oak gall wasps Neuropterus quercusbaccarum and Neuroterus numismalis respectievly. The asexual generations and the sexual generations are found on Q. robur leaves together.