title: PLANT EVOLUTION. Convergent evolution of strigolactone perception enabled host detection in parasitic plants.
abstract: Obligate parasitic plants in the Orobanchaceae germinate after sensing plant hormones, strigolactones, exuded from host roots. In Arabidopsis thaliana, the α/β-hydrolase D14 acts as a strigolactone receptor that controls shoot branching, whereas its ancestral paralog, KAI2, mediates karrikin-specific germination responses. We observed that KAI2, but not D14, is present at higher copy numbers in parasitic species than in nonparasitic relatives. KAI2 paralogs in parasites are distributed into three phylogenetic clades. The fastest-evolving clade, KAI2d, contains the majority of KAI2 paralogs. Homology models predict that the ligand-binding pockets of KAI2d resemble D14. KAI2d transgenes confer strigolactone-specific germination responses to Arabidopsis thaliana. Thus, the KAI2 paralogs D14 and KAI2d underwent convergent evolution of strigolactone recognition, respectively enabling developmental responses to strigolactones in angiosperms and host detection in parasites.
authors.affiliation: Department of Genetics, University of Georgia, Athens, GA 30602, USA.
authors.forename: Caitlin E
authors.initials: CE
authors.lastname: Conn
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Rohan
authors.initials: R
authors.lastname: Bythell-Douglas
authors.affiliation: Department of Genetics, University of Georgia, Athens, GA 30602, USA.
authors.forename: Drexel
authors.initials: D
authors.lastname: Neumann
authors.affiliation: RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Yoshida
authors.affiliation: Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA.
authors.forename: Bryan
authors.initials: B
authors.lastname: Whittington
authors.affiliation: Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA.
authors.forename: James H
authors.initials: JH
authors.lastname: Westwood
authors.affiliation: RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Shirasu
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Charles S
authors.initials: CS
authors.lastname: Bond
authors.affiliation: Department of Genetics, University of Georgia, Athens, GA 30602, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Dyer
authors.affiliation: Department of Genetics, University of Georgia, Athens, GA 30602, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Nelson
mesh_terms: D017360:Arabidopsis / Q000378:metabolism* / Q000469:parasitology*; D029681:Arabidopsis Proteins / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D005075:Biological Evolution; D018628:Gene Dosage; D018525:Germination; D006573:Heterocyclic Compounds, 1-Ring / Q000378:metabolism*; D006790:Host-Parasite Interactions; D006867:Hydrolases / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D007783:Lactones / Q000378:metabolism*; D031670:Orobanchaceae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism / Q000469:parasitology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D006573:Heterocyclic Compounds, 1-Ring; D007783:Lactones; D010937:Plant Growth Regulators; C558280:HTL protein, Arabidopsis; D006867:Hydrolases