4-Hydroxyphenylpyruvate dioxygenase(HPPD)is an important target for both drug and pesticide discovery.As a typical Fe(II)-dependent dioxygenase,HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic a...4-Hydroxyphenylpyruvate dioxygenase(HPPD)is an important target for both drug and pesticide discovery.As a typical Fe(II)-dependent dioxygenase,HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic acid(HPPA)to homogentisic acid(HGA).The binding mode of HPPA in the catalytic pocket of HPPD is a focus of research interests.Recently,we reported the crystal structure of Arabidopsis thaliana HPPD(At HPPD)complexed with HPPA and a cobalt ion,which was supposed to mimic the pre-reactive structure of At HPPD-HPPA-Fe(II).Unexpectedly,the present study shows that the restored At HPPD-HPPA-Fe(II)complex is still nonreactive toward the bound dioxygen.QM/MM and QM calculations reveal that the HPPA resists the electrophilic attacking of the bound dioxygen by the trim of its phenyl ring,and the residue Phe381 plays a key role in orienting the phenyl ring.Kinetic study on the F381 A mutant reveals that the HPPD-HPPA complex observed in the crystal structure should be an intermediate of the substrate transportation instead of the pre-reactive complex.More importantly,the binding mode of the HPPA in this complex is shared with several well-known HPPD inhibitors,suggesting that these inhibitors resist the association of dioxygen(and exert their inhibitory roles)in the same way as the HPPA.The present study provides insights into the inhibition mechanism of HPPD inhibitors.展开更多
Stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is a catastrophic disease that threatens global wheat yield.Yr10 is a race-specific all-stage disease resistance gene in wheat.However,the resistance mechan...Stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is a catastrophic disease that threatens global wheat yield.Yr10 is a race-specific all-stage disease resistance gene in wheat.However,the resistance mechanism of Yr10 is poorly characterized.Therefore,to elucidate the potential molecular mechanism mediated by Yr10,transcriptomic sequencing was performed at 0,18,and 48 h post-inoculation(hpi)of compatible wheat Avocet S(AvS)and incompatible near-isogenic line(NIL)AvS+Yr10 inoculated with Pst race CYR32.Respectively,227,208,and 4050 differentially expressed genes(DEGs)were identified at 0,18,and 48 hpi between incompatible and compatible interaction.The response of Yr10 to stripe rust involved various processes and activities,as indicated by the results of Gene Ontology(GO)enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis.Specifically,the response included photosynthesis,defense response to fungus,metabolic processes related to salicylic acid(SA)and jasmonic acid(JA),and activities related to reactive oxygen species(ROS).Ten candidate genes were selected for qRT-PCR verification and the results showed that the transcriptomic data was reliable.Through the functional analysis of candidate genes by the virus-induced gene silencing(VIGS)system,it was found that the gene TaHPPD(4-hydroxyphenylpyruvate dioxygenase)negatively regulated the resistance of wheat to stripe rust by affecting SA signaling,pathogenesis-related(PR)gene expression,and ROS clearance.Our study provides insight into Yr10-mediated resistance in wheat.展开更多
基金supported by the National Key R&D Program(No.2018YFD0200100)National Natural Science Foundation of China(Nos.21837001,21273089,22007035,U20A2038)+3 种基金the Open Project Fund of the Key Laboratory of the Pesticides and Chemical Biology of Central China Normal University(No.2018-A01)the Fundamental Research Funds for the South-Central University for Nationalities(No.CZW20020)the Fundamental Research Funds for the Central Universities(No.KJ02072020-0657)Hubei Province Natural Science Foundation(No.2020CFB487)。
文摘4-Hydroxyphenylpyruvate dioxygenase(HPPD)is an important target for both drug and pesticide discovery.As a typical Fe(II)-dependent dioxygenase,HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic acid(HPPA)to homogentisic acid(HGA).The binding mode of HPPA in the catalytic pocket of HPPD is a focus of research interests.Recently,we reported the crystal structure of Arabidopsis thaliana HPPD(At HPPD)complexed with HPPA and a cobalt ion,which was supposed to mimic the pre-reactive structure of At HPPD-HPPA-Fe(II).Unexpectedly,the present study shows that the restored At HPPD-HPPA-Fe(II)complex is still nonreactive toward the bound dioxygen.QM/MM and QM calculations reveal that the HPPA resists the electrophilic attacking of the bound dioxygen by the trim of its phenyl ring,and the residue Phe381 plays a key role in orienting the phenyl ring.Kinetic study on the F381 A mutant reveals that the HPPD-HPPA complex observed in the crystal structure should be an intermediate of the substrate transportation instead of the pre-reactive complex.More importantly,the binding mode of the HPPA in this complex is shared with several well-known HPPD inhibitors,suggesting that these inhibitors resist the association of dioxygen(and exert their inhibitory roles)in the same way as the HPPA.The present study provides insights into the inhibition mechanism of HPPD inhibitors.
基金supported by National Key R&D Program of China(2021YFD1401000)National Natural Science Foundation of China(32172424)the 111 Project from the Ministry of Education of China(BP0719026).
文摘Stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is a catastrophic disease that threatens global wheat yield.Yr10 is a race-specific all-stage disease resistance gene in wheat.However,the resistance mechanism of Yr10 is poorly characterized.Therefore,to elucidate the potential molecular mechanism mediated by Yr10,transcriptomic sequencing was performed at 0,18,and 48 h post-inoculation(hpi)of compatible wheat Avocet S(AvS)and incompatible near-isogenic line(NIL)AvS+Yr10 inoculated with Pst race CYR32.Respectively,227,208,and 4050 differentially expressed genes(DEGs)were identified at 0,18,and 48 hpi between incompatible and compatible interaction.The response of Yr10 to stripe rust involved various processes and activities,as indicated by the results of Gene Ontology(GO)enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis.Specifically,the response included photosynthesis,defense response to fungus,metabolic processes related to salicylic acid(SA)and jasmonic acid(JA),and activities related to reactive oxygen species(ROS).Ten candidate genes were selected for qRT-PCR verification and the results showed that the transcriptomic data was reliable.Through the functional analysis of candidate genes by the virus-induced gene silencing(VIGS)system,it was found that the gene TaHPPD(4-hydroxyphenylpyruvate dioxygenase)negatively regulated the resistance of wheat to stripe rust by affecting SA signaling,pathogenesis-related(PR)gene expression,and ROS clearance.Our study provides insight into Yr10-mediated resistance in wheat.
