title: Targeting Hormone-Related Pathways to Improve Grain Yield in Rice: A Chemical Approach.
abstract: Sink/source relationships, regulating the mobilization of stored carbohydrates from the vegetative tissues to the grains, are of key importance for grain filling and grain yield. We used different inhibitors of plant hormone action to assess their effects on grain yield and on the expression of hormone-associated genes. Among the tested chemicals, 2-indol-3-yl-4-oxo-4-phenylbutanoic acid (PEO-IAA; antagonist of auxin receptor), nordihydroguaiaretic acid (NDGA; abscisic acid (ABA) biosynthesis inhibitor), and 2-aminoisobutyric acid (AIB; ethylene biosynthesis inhibitor) improved grain yield in a concentration dependent manner. These effects were also dependent on the plant developmental stage. NDGA and AIB treatments induced an increase in photosynthesis in flag leaves concomitant to the increments of starch content in flag leaves and grains. NDGA inhibited the expression of ABA-responsive gene, but did not significantly decrease ABA content. Instead, NDGA significantly decreased jasmonic acid and jasmonic acid-isoleucine. Our results support the notion that the specific inhibition of jasmonic acid and ethylene biosynthesis resulted in grain yield increase in rice.
authors.affiliation: Department of Plant Sciences, University of California Davis, Davis, California 95616, United States of America; Health and Crop Sciences Research Laboratory, Sumitomo Chemical Co. Ltd., Hyogo 665-8555, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tamaki
authors.affiliation: Department of Plant Sciences, University of California Davis, Davis, California 95616, United States of America.
authors.forename: Maria
authors.initials: M
authors.lastname: Reguera
authors.affiliation: Department of Plant Sciences, University of California Davis, Davis, California 95616, United States of America.
authors.forename: Yasser M
authors.initials: YM
authors.lastname: Abdel-Tawab
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Takebayashi
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kasahara
authors.affiliation: Department of Plant Sciences, University of California Davis, Davis, California 95616, United States of America.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Blumwald
mesh_terms: D000040:Abscisic Acid / Q000037:antagonists & inhibitors; D000621:Aminoisobutyric Acids / Q000494:pharmacology; D000069599:Crop Production / Q000379:methods; D003517:Cyclopentanes / Q000037:antagonists & inhibitors; D004305:Dose-Response Relationship, Drug; D005030:Ethylenes / Q000037:antagonists & inhibitors; D012275:Oryza / Q000737:chemistry / Q000254:growth & development* / Q000502:physiology; D054883:Oxylipins / Q000037:antagonists & inhibitors; D010788:Photosynthesis / Q000187:drug effects; D010937:Plant Growth Regulators / Q000037:antagonists & inhibitors / Q000502:physiology*; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins / Q000037:antagonists & inhibitors; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors; D013213:Starch / Q000032:analysis
chemical_list: D000621:Aminoisobutyric Acids; D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C046131:auxin receptor, plant; C100049:2-aminoisobutyric acid; C011006:jasmonic acid; D000040:Abscisic Acid; D013213:Starch; C036216:ethylene