Light is an environmental signaling,whereas Aux/IAA proteins and Auxin Response Factors(ARFs)are regulators of auxin signalling.Aux/IAA proteins are unstable,and their degradation dependents on 26S ubiquitin-proteasom...Light is an environmental signaling,whereas Aux/IAA proteins and Auxin Response Factors(ARFs)are regulators of auxin signalling.Aux/IAA proteins are unstable,and their degradation dependents on 26S ubiquitin-proteasome and is promoted by Auxin.Auxin binds directly to a SCF-type ubiquitin-protein ligase,TIR1,facilitates the interaction between Aux/IAA proteins and TIR1,and then the degradation of Aux/IAA proteins.A few studies have reported that some ARFs are also unstable proteins,and their degradation is also mediated by 26S proteasome.In this study,by using of antibodies recognizing endogenous ARF7 proteins,we found that protein stability of ARF7 was affected by light.By expressing MYC tagged ARF activators in protoplasts,we found that degradation of ARF7 was inhibited by 26 proteasome inhibitors.In addition,at least ARF5 and ARF19 were also unstable proteins,and degradation of ARF5 via 26S proteasome was further confirmed by using stable transformed plants overexpressing ARF5 with a GUS tag.展开更多
N-Hydroxypipecolic acid(NHP)is a signaling molecule crucial for systemic acquired resistance(SAR),a systemic immune response in plants that provides long-lasting and broad-spectrum protection against secondary pathoge...N-Hydroxypipecolic acid(NHP)is a signaling molecule crucial for systemic acquired resistance(SAR),a systemic immune response in plants that provides long-lasting and broad-spectrum protection against secondary pathogen infections.To identify negative regulators of NHP biosynthesis,we performed a forward genetic screen to search for mutants with elevated expression of the NHP biosynthesis gene FLAVIN-DEPENDENT MONOOXYGENASE 1(FMO1).Analysis of two constitutive expression of FMO1(cef)and one induced expression of FMO1(ief)mutants revealed that the AIPP3–PHD2–CPL2 protein complex,which is involved in the recognition of the histone modification H3K27me3 and transcriptional repression,contributes to the negative regulation of FMO1 expression and NHP biosynthesis.Our study suggests that epigenetic regulation plays a crucial role in controlling FMO1 expression and NHP levels in plants.展开更多
文摘Light is an environmental signaling,whereas Aux/IAA proteins and Auxin Response Factors(ARFs)are regulators of auxin signalling.Aux/IAA proteins are unstable,and their degradation dependents on 26S ubiquitin-proteasome and is promoted by Auxin.Auxin binds directly to a SCF-type ubiquitin-protein ligase,TIR1,facilitates the interaction between Aux/IAA proteins and TIR1,and then the degradation of Aux/IAA proteins.A few studies have reported that some ARFs are also unstable proteins,and their degradation is also mediated by 26S proteasome.In this study,by using of antibodies recognizing endogenous ARF7 proteins,we found that protein stability of ARF7 was affected by light.By expressing MYC tagged ARF activators in protoplasts,we found that degradation of ARF7 was inhibited by 26 proteasome inhibitors.In addition,at least ARF5 and ARF19 were also unstable proteins,and degradation of ARF5 via 26S proteasome was further confirmed by using stable transformed plants overexpressing ARF5 with a GUS tag.
文摘N-Hydroxypipecolic acid(NHP)is a signaling molecule crucial for systemic acquired resistance(SAR),a systemic immune response in plants that provides long-lasting and broad-spectrum protection against secondary pathogen infections.To identify negative regulators of NHP biosynthesis,we performed a forward genetic screen to search for mutants with elevated expression of the NHP biosynthesis gene FLAVIN-DEPENDENT MONOOXYGENASE 1(FMO1).Analysis of two constitutive expression of FMO1(cef)and one induced expression of FMO1(ief)mutants revealed that the AIPP3–PHD2–CPL2 protein complex,which is involved in the recognition of the histone modification H3K27me3 and transcriptional repression,contributes to the negative regulation of FMO1 expression and NHP biosynthesis.Our study suggests that epigenetic regulation plays a crucial role in controlling FMO1 expression and NHP levels in plants.
