Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide...Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide fludioxonil is a key agent for FCR control.Previous studies indicated that resistance to fludioxonil in F.pseudograminearum is primarily associated with altered expression levels of the FpOS1 gene,which encodes a hybrid histidine kinase.However,the roles of mutations in other FpOS genes and the molecular interactions between FpOS proteins and fludioxonil remain elusive.To address these gaps,we generated 16 fludioxonil-resistant mutants with heritable resistance traits by in vitro selection of four sensitive F.pseudograminearum isolates.These mutants exhibited high resistance levels,with resistance factors(RF)ranging from 633.73 to 8617.07.Compared to their parental isolates,the resistant mutants showed significantly reduced mycelial growth rate,sporulation capacity,and pathogenicity.They were also more sensitive to ionic,osmotic,and oxidative stresses and displayed compromised cell wall and membrane integrity.Fludioxonil demonstrated no cross-resistance with tebuconazole or pydiflumetofen;however,it exhibited weak positive crossresistance to pyraclostrobin and moderate positive cross-resistance to iprodione.Fludioxonil treatment significantly promoted glycerol synthesis and inhibited deoxynivalenol(DON)production in parental isolates,whereas these regulatory effects were markedly attenuated in the resistant mutants.Mutation analysis identified mutation sites in FpOS1,FpOS4,and FpOS5 genes,with a lower mutation frequency in FpOS1 and no mutations detected in FpOS2.Molecular docking indicated that amino acid substitutions in FpOS4 and FpOS5 significantly reduced the binding affinity of fludioxonil to these target proteins.In conclusion,F.pseudograminearum poses a moderate risk of resistance to fludioxonil.Point mutations in FpOS4 and FpOS5 genes emerge as key molecular drivers of resistance,likely by diminishing the binding affinity between the fungicide and its proteins.This study clarifies the molecular basis of fludioxonil resistance in F.pseudograminearum and provides a scientific rationale for the judicious use of this fungicide in managing FCR.展开更多
OBJECTIVE:To explore the nature of ascendingdescending-floating-sinking of Traditional Chinese Medicine on normal rats using gonadotropin-releasing hormone(GnRh).METHODS:Normal male Sprague-Dawley rats were orally adm...OBJECTIVE:To explore the nature of ascendingdescending-floating-sinking of Traditional Chinese Medicine on normal rats using gonadotropin-releasing hormone(GnRh).METHODS:Normal male Sprague-Dawley rats were orally administered six floating Chinese medicines and seven sinking Chinese medicines for 14 d.Then,GnRh and relevant indicators were detected.Initially,the different effects of floating and sinking drugs on the body were explored.To verify the effects of floating and sinking drugs on the body,normal rats were orally administered Mahuang(Herba Ephedra Sinica)and Tinglizi(Semen Lepidii Apetali)for 14 d.Then,GnRh antagonists were administered.We observed the changes of relevant indicators and clarified the correlation between GnRh and the laws of floating and sinking.RESULTS:Floating Chinese medicines significantly increased the testicular coefficients;GnRh level in the serum;the protein level of GnRh receptor(GnRhR)in the testis;and the mRNA levels of androgen receptor(AR),small C-terminal domain phosphatase(SCP)3,SCP2,SYCE1,SMC1 B,SMC3,and Rec8(P<0.01 or<0.05).Sinking Chinese medicines did not react similarly,while GnRh antagonists blocked the regulatory effect of Mahuang(Herba Ephedra Sinica)but did not affect Tinglizi(Semen Lepidii Apetali).CONCLUSIONS:GnRh may be closely related to the nature of ascending-descending-floating-sinking of Chinese medicine.Floating Chinese medicines may promote their medicinal properties by regulating Gn RH level;however,sinking Chinese medicines did not affect GnRh level.展开更多
基金Supported by Funding from the Henan Provincial Scientific and Technological Breakthrough Project(No.242102111113).
文摘Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide fludioxonil is a key agent for FCR control.Previous studies indicated that resistance to fludioxonil in F.pseudograminearum is primarily associated with altered expression levels of the FpOS1 gene,which encodes a hybrid histidine kinase.However,the roles of mutations in other FpOS genes and the molecular interactions between FpOS proteins and fludioxonil remain elusive.To address these gaps,we generated 16 fludioxonil-resistant mutants with heritable resistance traits by in vitro selection of four sensitive F.pseudograminearum isolates.These mutants exhibited high resistance levels,with resistance factors(RF)ranging from 633.73 to 8617.07.Compared to their parental isolates,the resistant mutants showed significantly reduced mycelial growth rate,sporulation capacity,and pathogenicity.They were also more sensitive to ionic,osmotic,and oxidative stresses and displayed compromised cell wall and membrane integrity.Fludioxonil demonstrated no cross-resistance with tebuconazole or pydiflumetofen;however,it exhibited weak positive crossresistance to pyraclostrobin and moderate positive cross-resistance to iprodione.Fludioxonil treatment significantly promoted glycerol synthesis and inhibited deoxynivalenol(DON)production in parental isolates,whereas these regulatory effects were markedly attenuated in the resistant mutants.Mutation analysis identified mutation sites in FpOS1,FpOS4,and FpOS5 genes,with a lower mutation frequency in FpOS1 and no mutations detected in FpOS2.Molecular docking indicated that amino acid substitutions in FpOS4 and FpOS5 significantly reduced the binding affinity of fludioxonil to these target proteins.In conclusion,F.pseudograminearum poses a moderate risk of resistance to fludioxonil.Point mutations in FpOS4 and FpOS5 genes emerge as key molecular drivers of resistance,likely by diminishing the binding affinity between the fungicide and its proteins.This study clarifies the molecular basis of fludioxonil resistance in F.pseudograminearum and provides a scientific rationale for the judicious use of this fungicide in managing FCR.
基金Supported by the National Key Research and Development Program:the Major Project for Research of the Modernization of TCM(No.2019YFC1708802)Henan Province high-level personnel special support:“Zhong Yuan One Thousand People Plan”-Zhongyuan Leading Talent(No.ZYQR201810080)Key Scientific Research Projects of Colleges and Universities of Henan Province(No.21A360014)
文摘OBJECTIVE:To explore the nature of ascendingdescending-floating-sinking of Traditional Chinese Medicine on normal rats using gonadotropin-releasing hormone(GnRh).METHODS:Normal male Sprague-Dawley rats were orally administered six floating Chinese medicines and seven sinking Chinese medicines for 14 d.Then,GnRh and relevant indicators were detected.Initially,the different effects of floating and sinking drugs on the body were explored.To verify the effects of floating and sinking drugs on the body,normal rats were orally administered Mahuang(Herba Ephedra Sinica)and Tinglizi(Semen Lepidii Apetali)for 14 d.Then,GnRh antagonists were administered.We observed the changes of relevant indicators and clarified the correlation between GnRh and the laws of floating and sinking.RESULTS:Floating Chinese medicines significantly increased the testicular coefficients;GnRh level in the serum;the protein level of GnRh receptor(GnRhR)in the testis;and the mRNA levels of androgen receptor(AR),small C-terminal domain phosphatase(SCP)3,SCP2,SYCE1,SMC1 B,SMC3,and Rec8(P<0.01 or<0.05).Sinking Chinese medicines did not react similarly,while GnRh antagonists blocked the regulatory effect of Mahuang(Herba Ephedra Sinica)but did not affect Tinglizi(Semen Lepidii Apetali).CONCLUSIONS:GnRh may be closely related to the nature of ascending-descending-floating-sinking of Chinese medicine.Floating Chinese medicines may promote their medicinal properties by regulating Gn RH level;however,sinking Chinese medicines did not affect GnRh level.
