It is well established that an abnormal tetrahydrofolate(THF)cycle causes the accumulation of hydrogen peroxide(H_(2)O_(2))and leaf senescence,however,the molecular mechanism underlying this relationship remains large...It is well established that an abnormal tetrahydrofolate(THF)cycle causes the accumulation of hydrogen peroxide(H_(2)O_(2))and leaf senescence,however,the molecular mechanism underlying this relationship remains largely unknown.Here,we reported a novel rice tetrahydrofolate cycle mutant,which exhibited H_(2)O_(2)accumulation and early leaf senescence phenotypes.Map-based cloning revealed that HPA1 encodes a tetrahydrofolate deformylase,and its deficiency led to the accumulation of tetrahydrofolate,5-formyl tetrahydrofolate and 10-formyl tetrahydrofolate,in contrast,a decrease in 5,10-methenyl-tetrahydrofolate.The expression of tetrahydrofolate cycle-associated genes encoding serine hydroxymethyl transferase,glycine decarboxylase and 5-formyl tetrahydrofolate cycloligase was significantly down-regulated.In addition,the accumulation of H_(2)O_(2)in hpa1 was not caused by elevated glycolate oxidation.Proteomics and enzyme activity analyses further revealed that mitochondria oxidative phosphorylation complex I and complex V were differentially expressed in hpa1,which was consistent with the H_(2)O_(2)accumulation in hpa1.In a further feeding assay with exogenous glutathione(GSH),a non-enzymatic antioxidant that consumes H_(2)O_(2),the H_(2)O_(2)accumulation and leaf senescence phenotypes of hpa1 were obviously compensated.Taken together,our findings suggest that the accumulation of H_(2)O_(2)in hpa1 may be mediated by an altered folate status and redox homeostasis,subsequently triggering leaf senescence.展开更多
基金the National Key Research and Development Program of China(2016YFD0101801)the National Natural Science Foundation of China(91735303 and 91335103)+2 种基金the Natural Science Foundation of Zhejiang(LY18C130010,LY18C130009,and LY20C130004)the Science and Technology Project of Hangzhou(20180432B03,20180432B09,and 20180432B04)the Foundation of Zhejiang Education Department(Y201431296)。
文摘It is well established that an abnormal tetrahydrofolate(THF)cycle causes the accumulation of hydrogen peroxide(H_(2)O_(2))and leaf senescence,however,the molecular mechanism underlying this relationship remains largely unknown.Here,we reported a novel rice tetrahydrofolate cycle mutant,which exhibited H_(2)O_(2)accumulation and early leaf senescence phenotypes.Map-based cloning revealed that HPA1 encodes a tetrahydrofolate deformylase,and its deficiency led to the accumulation of tetrahydrofolate,5-formyl tetrahydrofolate and 10-formyl tetrahydrofolate,in contrast,a decrease in 5,10-methenyl-tetrahydrofolate.The expression of tetrahydrofolate cycle-associated genes encoding serine hydroxymethyl transferase,glycine decarboxylase and 5-formyl tetrahydrofolate cycloligase was significantly down-regulated.In addition,the accumulation of H_(2)O_(2)in hpa1 was not caused by elevated glycolate oxidation.Proteomics and enzyme activity analyses further revealed that mitochondria oxidative phosphorylation complex I and complex V were differentially expressed in hpa1,which was consistent with the H_(2)O_(2)accumulation in hpa1.In a further feeding assay with exogenous glutathione(GSH),a non-enzymatic antioxidant that consumes H_(2)O_(2),the H_(2)O_(2)accumulation and leaf senescence phenotypes of hpa1 were obviously compensated.Taken together,our findings suggest that the accumulation of H_(2)O_(2)in hpa1 may be mediated by an altered folate status and redox homeostasis,subsequently triggering leaf senescence.
