title: Evidence That Chlorinated Auxin Is Restricted to the Fabaceae But Not to the Fabeae.
abstract: Auxin is a pivotal plant hormone, usually occurring in the form of indole-3-acetic acid (IAA). However, in maturing pea (Pisum sativum) seeds, the level of the chlorinated auxin, 4-chloroindole-3-acetic acid (4-Cl-IAA), greatly exceeds that of IAA. A key issue is how plants produce halogenated compounds such as 4-Cl-IAA. To better understand this topic, we investigated the distribution of the chlorinated auxin. We show for the first time, to our knowledge, that 4-Cl-IAA is found in the seeds of Medicago truncatula, Melilotus indicus, and three species of Trifolium. Furthermore, we found no evidence that Pinus spp. synthesize 4-Cl-IAA in seeds, contrary to a previous report. The evidence indicates a single evolutionary origin of 4-Cl-IAA synthesis in the Fabaceae, which may provide an ideal model system to further investigate the action and activity of halogenating enzymes in plants.
authors.affiliation: School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Hong Kiat
authors.identifier: http://orcid.org/0000-0003-4180-3750
authors.initials: HK
authors.lastname: Lam
authors.affiliation: School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Scott A M
authors.initials: SA
authors.lastname: McAdam
authors.affiliation: School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Erin L
authors.initials: EL
authors.lastname: McAdam
authors.affiliation: School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia john.ross@utas.edu.au.
authors.forename: John J
authors.identifier: http://orcid.org/0000-0003-3665-2062
authors.initials: JJ
authors.lastname: Ross
mesh_terms: D002851:Chromatography, High Pressure Liquid; D007887:Fabaceae / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism; D054879:Halogenation; D007210:Indoleacetic Acids / Q000378:metabolism*; D010802:Phylogeny; D012639:Seeds / Q000378:metabolism; D013045:Species Specificity; D053719:Tandem Mass Spectrometry
chemical_list: D007210:Indoleacetic Acids; C096198:4-chloroindole-3-acetic acid