title: The rice hydroperoxide lyase OsHPL3 functions in defense responses by modulating the oxylipin pathway.
abstract: As important signal molecules, jasmonates (JAs) and green leaf volatiles (GLVs) play diverse roles in plant defense responses against insect pests and pathogens. However, how plants employ their specific defense responses by modulating the levels of JA and GLVs remains unclear. Here, we describe identification of a role for the rice HPL3 gene, which encodes a hydroperoxide lyase (HPL), OsHPL3/CYP74B2, in mediating plant-specific defense responses. The loss-of-function mutant hpl3-1 produced disease-resembling lesions spreading through the whole leaves. A biochemical assay revealed that OsHPL3 possesses intrinsic HPL activity, hydrolyzing hydroperoxylinolenic acid to produce GLVs. The hpl3-1 plants exhibited enhanced induction of JA, trypsin proteinase inhibitors and other volatiles, but decreased levels of GLVs including (Z)-3-hexen-1-ol. OsHPL3 positively modulates resistance to the rice brown planthopper [BPH, Nilaparvata lugens (Stål)] but negatively modulates resistance to the rice striped stem borer [SSB, Chilo suppressalis (Walker)]. Moreover, hpl3-1 plants were more attractive to a BPH egg parasitoid, Anagrus nilaparvatae, than the wild-type, most likely as a result of increased release of BPH-induced volatiles. Interestingly, hpl3-1 plants also showed increased resistance to bacterial blight (Xanthomonas oryzae pv. oryzae). Collectively, these results indicate that OsHPL3, by affecting the levels of JA, GLVs and other volatiles, modulates rice-specific defense responses against different invaders.
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Tong
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Qi
authors.forename: Xudong
authors.initials: X
authors.lastname: Zhu
authors.forename: Bizeng
authors.initials: B
authors.lastname: Mao
authors.forename: Longjun
authors.initials: L
authors.lastname: Zeng
authors.forename: Baohui
authors.initials: B
authors.lastname: Wang
authors.forename: Qun
authors.initials: Q
authors.lastname: Li
authors.forename: Guoxin
authors.initials: G
authors.lastname: Zhou
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Xu
authors.forename: Yonggen
authors.initials: Y
authors.lastname: Lou
authors.forename: Zuhua
authors.initials: Z
authors.lastname: He
mesh_terms: D000446:Aldehyde-Lyases / Q000378:metabolism*; D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005260:Female; D060434:Herbivory; D007313:Insecta / Q000502:physiology*; D009154:Mutation; D012275:Oryza / Q000201:enzymology / Q000382:microbiology / Q000502:physiology*; D054883:Oxylipins / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010940:Plant Proteins; D014361:Trypsin Inhibitors; D055549:Volatile Organic Compounds; C011006:jasmonic acid; D003577:Cytochrome P-450 Enzyme System; D000446:Aldehyde-Lyases; C054540:hydroperoxide lyase; D020156:Salicylic Acid