C-terminal region of plant ferredoxin-like protein is required to enhance resistance to bacterial disease in Arabidopsis thaliana.
Protein phosphorylation is an important biological process associated with elicitor-induced defense responses in plants. In a previous report, we described how plant ferredoxin-like protein (PFLP) in transgenic plants enhances resistance to bacterial pathogens associated with the hypersensitive response (HR). PFLP possesses a putative casein kinase II phosphorylation (CK2P) site at the C-terminal in which phosphorylation occurs rapidly during defense response. However, the contribution of this site to the enhancement of disease resistance and the intensity of HR has not been clearly demonstrated. In this study, we generated two versions of truncated PFLP, PEC (extant CK2P site) and PDC (deleted CK2P site), and assessed their ability to trigger HR through harpin (HrpZ) derived from Pseudomonas syringae as well as their resistance to Ralstonia solanacearum. In an infiltration assay of HrpZ, PEC intensified harpin-mediated HR; however, PDC negated this effect. Transgenic plants expressing these versions indicate that nonphosphorylated PFLP loses its ability to induce HR or enhance disease resistance against R. solanacearum. Interestingly, the CK2P site of PFLP is required to induce the expression of the NADPH oxidase gene, AtrbohD, which is a reactive oxygen species producing enzyme. This was further confirmed by evaluating the HR on NADPH oxidase in mutants of Arabidopsis. As a result, we have concluded that the CK2P site is required for the phosphorylation of PFLP to enhance disease resistance.
Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei, Taiwan.
Yi-Hsien
YH
Lin
Hsiang-En
HE
Huang
Yen-Ru
YR
Chen
Pei-Luan
PL
Liao
Ching-Lian
CL
Chen
Teng-Yung
TY
Feng
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000494:pharmacology*; D002212:Capsicum / Q000235:genetics; D005288:Ferredoxins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D044224:Pseudomonas syringae / Q000235:genetics; D043368:Ralstonia solanacearum / Q000472:pathogenicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors
D029681:Arabidopsis Proteins; D001425:Bacterial Outer Membrane Proteins; D005288:Ferredoxins; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; C474922:plant ferredoxin-like protein, Capsicum annuum; C087295:HrpZ protein, Pseudomonas syringae