Data from: Transcriptomics of host-specific interactions in natural populations of the parasitic plant purple witchweed (Striga hermonthica)

Host-specific interactions can maintain genetic and phenotypic diversity
in parasites that attack multiple host species. Host diversity, in turn,
may promote parasite diversity by selection for genetic divergence or
plastic responses to host type. The parasitic weed purple witchweed
[Striga hermonthica (Delile) Benth.] causes devastating crop losses in
sub-Saharan Africa and is capable of infesting a wide range of grass
hosts. Despite some evidence for host adaptation and host-by-Striga
genotype interactions, little is known about intraspecific Striga genomic
diversity. Here we present a study of transcriptomic diversity in
populations of S. hermonthica growing on different hosts (maize [Zea mays
L.] vs. grain sorghum [Sorghum bicolor (L.) Moench]). We examined gene
expression variation and differences in allelic frequency in expressed
genes of aboveground tissues from populations in western Nigeria
parasitizing each host. Despite low levels of host-based genome-wide
differentiation, we identified a set of parasite transcripts specifically
associated with each host. Parasite genes in several different functional
categories implicated as important in host–parasite interactions differed
in expression level and allele on different hosts, including genes
involved in nutrient transport, defense and pathogenesis, and plant
hormone response. Overall, we provide a set of candidate transcripts that
demonstrate host-specific interactions in vegetative tissues of the
emerged parasite S. hermonthica. Our study shows how signals of
host-specific processes can be detected aboveground, expanding the focus
of host–parasite interactions beyond the haustorial connection.