title: The Bphi008a gene interacts with the ethylene pathway and transcriptionally regulates MAPK genes in the response of rice to brown planthopper feeding.
abstract: We examined ways in which the Brown planthopper induced008a (Bphi008a; AY256682) gene of rice (Oryza sativa) enhances the plant's resistance to a specialist herbivore, the brown planthopper (BPH; Nilaparvata lugens). Measurement of the expression levels of ethylene synthases and of ethylene emissions showed that BPH feeding rapidly initiated the ethylene signaling pathway and up-regulated Bphi008a transcript levels after 6 to 96 h of feeding. In contrast, blocking ethylene transduction (using 1-methylcyclopropene) reduced Bphi008a transcript levels in wild-type plants fed upon by BPH. In vitro kinase assays showed that Bphi008a can be phosphorylated by rice Mitogen-activated Protein Kinase5 (OsMPK5), and yeast two-hybrid assays demonstrated that the carboxyl-terminal proline-rich region of Bphi008a interacts directly with this kinase. Furthermore, bimolecular fluorescence complementation assays showed that this interaction occurs in the nucleus. Subsequently, we found that Bphi008a up-regulation and down-regulation were accompanied by different changes in transcription levels of OsMPK5, OsMPK12, OsMPK13, and OsMPK17 in transgenic plants. Immunoblot analysis also showed that the OsMPK5 protein level increased in overexpressing plants and decreased in RNA interference plants after BPH feeding. In transgenic lines, changes in the expression levels of several enzymes that are important components of the defenses against the BPH were also observed. Finally, yeast two-hybrid screening results showed that Bphi008a is able to interact with a b-ZIP transcription factor (OsbZIP60) and a RNA polymerase polypeptide (SDRP).
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Hu
authors.forename: Jiangbo
authors.initials: J
authors.lastname: Zhou
authors.forename: Xinxin
authors.initials: X
authors.lastname: Peng
authors.forename: Henghao
authors.initials: H
authors.lastname: Xu
authors.forename: Caixiang
authors.initials: C
authors.lastname: Liu
authors.forename: Bo
authors.initials: B
authors.lastname: Du
authors.forename: Hongyu
authors.initials: H
authors.lastname: Yuan
authors.forename: Lili
authors.initials: L
authors.lastname: Zhu
authors.forename: Guangcun
authors.initials: G
authors.lastname: He
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D005030:Ethylenes / Q000378:metabolism*; D005247:Feeding Behavior / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D006430:Hemiptera / Q000502:physiology*; D007113:Immunity, Innate / Q000235:genetics; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology / Q000235:genetics* / Q000276:immunology / Q000469:parasitology*; D010766:Phosphorylation; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000469:parasitology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011485:Protein Binding; D021381:Protein Transport; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D036226:Seedlings / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D013347:Subcellular Fractions / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D005030:Ethylenes; D010940:Plant Proteins; C036216:ethylene; D020928:Mitogen-Activated Protein Kinases