In plants, recognition of small secreted peptides, such as damage/danger-associated molecular patterns(DAMPs), regulates diverse processes,includingstressandimmune responses. Here, we identified an SGPS(Ser-Gly-Pro-Se...In plants, recognition of small secreted peptides, such as damage/danger-associated molecular patterns(DAMPs), regulates diverse processes,includingstressandimmune responses. Here, we identified an SGPS(Ser-Gly-Pro-Ser) motif-containing peptide, Nicotiana tabacum NtPROPPI, and its two homologs in Nicotiana benthamiana, NbPROPPI1 and NbPROPPI2. Phytophthora parasitica infection and salicylic acid(SA) treatment induced NbPROPPI1/2 expression. Moreover, SignalP predicted that the 89-amino acid NtPROPPI includes a 24-amino acid N-terminal signal peptide and NbPROPPI1/2-GFP fusion proteins were mainly localized to the periplasm. Transient expression of NbPROPPI1/2 inhibited P.parasiticacolonization,andNbPROPPI1/2 knockdown rendered plants more susceptible to P. parasitica. An eight-amino-acid segment in the NbPROPPI1 C-terminus was essential for its immune function and a synthetic 20-residue peptide, NbPPI1, derived from the C-terminus of NbPROPPI1 provoked significant immune responses in N. benthamiana. These responses led to enhanced accumulation of reactive oxygen species, activation of mitogen-activated protein kinases, and up-regulation of the defense genes Flg22-induced receptor-like kinase(FRK) and WRKY DNA-binding protein 33(WRKY33). The NbPPI1-induced defense responses require Brassinosteroid insensitive1-associated receptor kinase 1(BAK1). These results suggest that NbPPI1 functions as a DAMP in N. benthamiana;this novel DAMP provides a potentially useful target for improving plant resistance to Pytophthora pathogens.展开更多
基金This work was supported by the National Natural Science Foundation of China(31125022 and 31930094)the China Agriculture Research System(CARS-09)the Program of Introducing Talents of Innovative Discipline to Universities(Project 111)from the State Administration of Foreign Experts Affairs(#B18042)。
文摘In plants, recognition of small secreted peptides, such as damage/danger-associated molecular patterns(DAMPs), regulates diverse processes,includingstressandimmune responses. Here, we identified an SGPS(Ser-Gly-Pro-Ser) motif-containing peptide, Nicotiana tabacum NtPROPPI, and its two homologs in Nicotiana benthamiana, NbPROPPI1 and NbPROPPI2. Phytophthora parasitica infection and salicylic acid(SA) treatment induced NbPROPPI1/2 expression. Moreover, SignalP predicted that the 89-amino acid NtPROPPI includes a 24-amino acid N-terminal signal peptide and NbPROPPI1/2-GFP fusion proteins were mainly localized to the periplasm. Transient expression of NbPROPPI1/2 inhibited P.parasiticacolonization,andNbPROPPI1/2 knockdown rendered plants more susceptible to P. parasitica. An eight-amino-acid segment in the NbPROPPI1 C-terminus was essential for its immune function and a synthetic 20-residue peptide, NbPPI1, derived from the C-terminus of NbPROPPI1 provoked significant immune responses in N. benthamiana. These responses led to enhanced accumulation of reactive oxygen species, activation of mitogen-activated protein kinases, and up-regulation of the defense genes Flg22-induced receptor-like kinase(FRK) and WRKY DNA-binding protein 33(WRKY33). The NbPPI1-induced defense responses require Brassinosteroid insensitive1-associated receptor kinase 1(BAK1). These results suggest that NbPPI1 functions as a DAMP in N. benthamiana;this novel DAMP provides a potentially useful target for improving plant resistance to Pytophthora pathogens.
