title: Positive regulatory role of strigolactone in plant responses to drought and salt stress.
abstract: This report provides direct evidence that strigolactone (SL) positively regulates drought and high salinity responses in Arabidopsis. Both SL-deficient and SL-response [more axillary growth (max)] mutants exhibited hypersensitivity to drought and salt stress, which was associated with shoot- rather than root-related traits. Exogenous SL treatment rescued the drought-sensitive phenotype of the SL-deficient mutants but not of the SL-response mutant, and enhanced drought tolerance of WT plants, confirming the role of SL as a positive regulator in stress response. In agreement with the drought-sensitive phenotype, max mutants exhibited increased leaf stomatal density relative to WT and slower abscisic acid (ABA)-induced stomatal closure. Compared with WT, the max mutants exhibited increased leaf water loss rate during dehydration and decreased ABA responsiveness during germination and postgermination. Collectively, these results indicate that cross-talk between SL and ABA plays an important role in integrating stress signals to regulate stomatal development and function. Additionally, a comparative microarray analysis of the leaves of the SL-response max2 mutant and WT plants under normal and dehydrative conditions revealed an SL-mediated network controlling plant responses to stress via many stress- and/or ABA-responsive and cytokinin metabolism-related genes. Our results demonstrate that plants integrate multiple hormone-response pathways for adaptation to environmental stress. Based on our results, genetic modulation of SL content/response could be applied as a potential approach to reduce the negative impact of abiotic stress on crop productivity.
authors.affiliation: Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan.
authors.forename: Chien Van
authors.initials: CV
authors.lastname: Ha
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Leyva-González
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Osakabe
authors.forename: Uyen Thi
authors.initials: UT
authors.lastname: Tran
authors.forename: Rie
authors.initials: R
authors.lastname: Nishiyama
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Maho
authors.initials: M
authors.lastname: Tanaka
authors.forename: Motoaki
authors.initials: M
authors.lastname: Seki
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Nguyen Van
authors.initials: NV
authors.lastname: Dong
authors.forename: Kazuko
authors.initials: K
authors.lastname: Yamaguchi-Shinozaki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Luis
authors.initials: L
authors.lastname: Herrera-Estrella
authors.forename: Lam-Son Phan
authors.initials: LS
authors.lastname: Tran
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology*; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology*; D018525:Germination / Q000187:drug effects / Q000502:physiology; D007783:Lactones / Q000494:pharmacology*; D046228:Microarray Analysis; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology*; D054712:Salinity; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D007783:Lactones; D000040:Abscisic Acid; C483518:strigol
keywords: hormonal regulation; plant adaptation; transcriptome analysis