Data from: Independent evolution of ancestral and novel defenses in a genus of toxic plants (Erysimum, Brassicaceae)

Phytochemical diversity is thought to result from coevolutionary cycles as
specialization in herbivores imposes diversifying selection on plant
chemical defenses. Plants in the speciose genus Erysimum (Brassicaceae)
produce both ancestral glucosinolates and evolutionarily novel
cardenolides as defenses. Here we test macroevolutionary hypotheses on
co-expression, co-regulation, and diversification of these potentially
redundant defenses across this genus. We sequenced and assembled the
genome of E. cheiranthoides and foliar transcriptomes of 47 additional
Erysimum species to construct a phylogeny from 9,869 orthologous genes,
revealing several geographic clades but also high levels of gene
discordance. Concentrations, inducibility, and diversity of the two
defenses varied independently among species, with no evidence for
trade-offs. Closely related, geographically co-occurring species shared
similar cardenolide traits, but not glucosinolate traits, likely as a
result of specific selective pressures acting on each defense. Ancestral
and novel chemical defenses in Erysimum thus appear to provide
complementary rather than redundant functions.