title: Plant Stress Tolerance Requires Auxin-Sensitive Aux/IAA Transcriptional Repressors.
abstract: The Aux/IAA proteins are auxin-sensitive repressors that mediate diverse physiological and developmental processes in plants [1, 2]. There are 29 Aux/IAA genes in Arabidopsis that exhibit unique but partially overlapping patterns of expression [3]. Although some studies have suggested that individual Aux/IAA genes have specialized function, genetic analyses of the family have been limited by the scarcity of loss-of-function phenotypes [4]. Furthermore, with a few exceptions, our knowledge of the factors that regulate Aux/IAA expression is limited [1, 5]. We hypothesize that transcriptional control of Aux/IAA genes plays a central role in the establishment of the auxin-signaling pathways that regulate organogenesis, growth, and environmental response. Here, we describe a screen for transcription factors (TFs) that regulate the Aux/IAA genes. We identify TFs from 38 families, including 26 members of the DREB/CBF family. Several DREB/CBF TFs directly promote transcription of the IAA5 and IAA19 genes in response to abiotic stress. Recessive mutations in these IAA genes result in decreased tolerance to stress conditions, demonstrating a role for auxin in abiotic stress. Our results demonstrate that stress pathways interact with the auxin gene regulatory network (GRN) through transcription of the Aux/IAA genes. We propose that the Aux/IAA genes function as hubs that integrate genetic and environmental information to achieve the appropriate developmental or physiological outcome.
authors.affiliation: Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Eilon
authors.initials: E
authors.lastname: Shani
authors.affiliation: Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Salehin
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Yuqin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Sabrina E
authors.initials: SE
authors.lastname: Sanchez
authors.affiliation: Department of Molecular and Structural Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Colleen
authors.initials: C
authors.lastname: Doherty
authors.affiliation: Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Renhou
authors.initials: R
authors.lastname: Wang
authors.affiliation: Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Cristina Castillejo
authors.initials: CC
authors.lastname: Mangado
authors.affiliation: Genome Analysis Laboratory, Howard Hughes Medical Institute and The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Song
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Iris
authors.initials: I
authors.lastname: Tal
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Odelia
authors.initials: O
authors.lastname: Pisanty
authors.affiliation: Genome Analysis Laboratory, Howard Hughes Medical Institute and The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Ecker
authors.affiliation: Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Steve A
authors.initials: SA
authors.lastname: Kay
authors.affiliation: Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Jose
authors.initials: J
authors.lastname: Pruneda-Paz
authors.affiliation: Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. Electronic address: mestelle@ucsd.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Estelle
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007210:Indoleacetic Acids / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D030821:Plants, Genetically Modified; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D012097:Repressor Proteins
keywords: Aux/IAA; abiotic stress; auxin; plant hormone; repressor