Genetic variation in a plant-parasitic nematode is associated with host gene expression changes conserved across evolutionarily distant host plants.

A hallmark of the interactions between endoparasites (parasites that live within plant tissue) and their hosts is the parasites' ability to hijack host gene expression to support their own existence. While a number of studies have been performed to identify plant genes that are recruited in this manner, there is much that remains unknown. One mechanism by which this behavior can be explored is by using a traditional genetics approach: identifying connections between genetic variation and phenotype variation. To that end, we leverage experiments examining tissue from 3 host plant species, infected with one of 2 genetically distinct strains of the endoparasite Meloidogyne hapla. Using RNA-Seq data, we identify plant gene expression patterns that differ according to the genetic background of the infecting parasite. We also show that parasite genotype-host expression phenotype associations are consistent across plant species. These results indicate that the plant genes recruited by the parasite are influenced by the parasite's genetic background and that these differential choices are conserved across evolutionarily distant hosts. We also leverage public data to identify conserved host expression differences when comparing M. hapla-infected plants to uninfected plants. Finally, we demonstrate that parasite gene expression varies according to the parasite's genetic background and show that these signals are also conserved under different host species.