On the origins and evolution of phytohormone signaling and biosynthesis in plants.

Phytohormones modulate nearly all aspects of plant biology.Phytohormone signaling and biosynthesis pathways have been characterized mainly through studies of angiosperms,particu-larly the model plant Arabidopsis thaliana(Blázquez et al.,2020).Phylogenetic analyses across plants provide insights into the origins and evolution of phytohormone signaling pathways(Wang et al.,2015).However,these studies come with one caveat:homology at the level of sequences does not necessarily demonstrate functional conservation.Due to the lack of functional verification,much remains obscure and contentious about the origins of phytohormone signaling and biosynthesis pathways.In a recent study,Jia et al.(2023)employed a combined approach of phylogenetic analysis and functional characterization to explore the origin and evolution of the signaling and biosynthesis pathways of salicylic acid(SA),a crucial plant defense hormone.