title: Effects of Light and Wounding on Jasmonates in Rice phyAphyC Mutants.
abstract: Jasmonates (JA) are lipid-derived plant hormones. They have been shown to be important regulators of photomorphogenesis, a developmental program in plants, which is activated by light through different red and blue light sensitive photoreceptors. In rice, inhibition of coleoptile growth by light is a central event in photomorphogenesis. This growth inhibition is impaired, when jasmonate biosynthesis is knocked out. Previously, we found that JASMONATE RESISTANT 1 (OsJAR1) transcripts were not induced in the phytochrome (phy) mutant phyAphyC. Therefore, in the current study we investigated the regulation of JA and its highly bioactive derivative (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile), as well as the transcriptional regulation of several JA-dependent genes both in wild type and phyAphyC mutant. JA and JA-Ile levels increased in the mutant seedlings in response to blue light. However, in phyAphyC mutant leaves, which were continuously wounded, JA and JA-Ile levels were lower compared to those in the wild type. Hence, the mutation of phyA and phyC has differential effects on jasmonate levels depending on the tissue and developmental stage. Our results suggest that the contribution of JA-Ile to signaling during photomorphogenesis of rice is minor, as coleoptile phenotypes of phyAphyC mutants resemble those of jasmonate-deficient mutants despite the fact that induction by blue light leads to higher levels of JA-Ile compared to the wild type. We postulate that phyA and phyC could control the activity of specific enzymes metabolizing JA to active derivatives.
authors.affiliation: Botanical Institute, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany. rita.brendel@kit.edu.
authors.forename: Rita
authors.initials: R
authors.lastname: Brendel
authors.affiliation: Botanical Institute, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany. katha.sv@gmx.de.
authors.forename: Katharina
authors.initials: K
authors.lastname: Svyatyna
authors.affiliation: RIKEN Plant Science Center, Tsurumi, Yokohama, Kanagawa 230-0045, Japan. jikumaru@psc.riken.jp.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Jikumaru
authors.affiliation: Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena 07745, Germany. reichelt@ice.mpg.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Reichelt
authors.affiliation: Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena 07745, Germany. amithoefer@ice.mpg.de.
authors.forename: Axel
authors.initials: A
authors.lastname: Mithöfer
authors.affiliation: Department of Plant Physiology, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan. mtakano@affrc.go.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Takano
authors.affiliation: RIKEN Plant Science Center, Tsurumi, Yokohama, Kanagawa 230-0045, Japan. ykamiya@postman.riken.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kamiya
authors.affiliation: Botanical Institute, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany. peter.nick@kit.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Nick
authors.affiliation: Botanical Institute, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany. michael.riemann@kit.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Riemann
keywords: JASMONATE RESISTANT 1; Oryza sativa L.; jasmonate; jasmonate-isoleucine; mechanical wounding; photomorphogenesis; phytochrome