title: silencing COI1 in rice increases susceptibility to chewing insects and impairs inducible defense.
abstract: The jasmonic acid (JA) pathway plays a key role in plant defense responses against herbivorous insects. CORONATINE INSENSITIVE1 (COI1) is an F-box protein essential for all jasmonate responses. However, the precise defense function of COI1 in monocotyledonous plants, especially in rice (Oryza sativa L.) is largely unknown. We silenced OsCOI1 in rice plants via RNA interference (RNAi) to determine the role of OsCOI1 in rice defense against rice leaf folder (LF) Cnaphalocrocis medinalis, a chewing insect, and brown planthopper (BPH) Nilaparvata lugens, a phloem-feeding insect. In wild-type rice plants (WT), the transcripts of OsCOI1 were strongly and continuously up-regulated by LF infestation and methyl jasmonate (MeJA) treatment, but not by BPH infestation. The abundance of trypsin protease inhibitor (TrypPI), and the enzymatic activities of polyphenol oxidase (PPO) and peroxidase (POD) were enhanced in response to both LF and BPH infestation, but the activity of lipoxygenase (LOX) was only induced by LF. The RNAi lines with repressed expression of OsCOI1 showed reduced resistance against LF, but no change against BPH. Silencing OsCOI1 did not alter LF-induced LOX activity and JA content, but it led to a reduction in the TrypPI content, POD and PPO activity by 62.3%, 48.5% and 27.2%, respectively. In addition, MeJA-induced TrypPI and POD activity were reduced by 57.2% and 48.2% in OsCOI1 RNAi plants. These results suggest that OsCOI1 is an indispensable signaling component, controlling JA-regulated defense against chewing insect (LF) in rice plants, and COI1 is also required for induction of TrypPI, POD and PPO in rice defense response to LF infestation.
authors.affiliation: State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Ministry of Agriculture, South China Agricultural University, Wushan, Guangzhou, People's Republic of China.
authors.forename: Mao
authors.initials: M
authors.lastname: Ye
authors.forename: Shi Ming
authors.initials: SM
authors.lastname: Luo
authors.forename: Jie Fen
authors.initials: JF
authors.lastname: Xie
authors.forename: Yan Fang
authors.initials: YF
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Yuan Yuan
authors.initials: YY
authors.lastname: Song
authors.forename: Keyan
authors.initials: K
authors.lastname: Zhu-Salzman
authors.forename: Ren Sen
authors.initials: RS
authors.lastname: Zeng
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000818:Animals; D004156:Catechol Oxidase / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D005260:Female; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000276:immunology; D006430:Hemiptera / Q000502:physiology*; D007915:Lepidoptera / Q000502:physiology*; D008409:Mastication; D012275:Oryza / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000276:immunology*; D054883:Oxylipins / Q000494:pharmacology; D009195:Peroxidase / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000378:metabolism
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D054883:Oxylipins; D010940:Plant Proteins; D012333:RNA, Messenger; D014361:Trypsin Inhibitors; C072239:methyl jasmonate; D004156:Catechol Oxidase; D009195:Peroxidase