摘要Nitrogen(N)deficiency causes early leaf senescence,resulting in accelerated whole-plant maturation and severely reduced crop yield.However,the molecular mechanisms underlying N-deficiency-induced early leaf senescence remain unclear,even in the model species Arabidopsis thaliana.In this study,we identified Growth,Development and Splicing 1(GDS1),a previously reported transcription factor,as a new regulator of nitrate(NO3-)signaling by a yeast-one-hybrid screen using a NO3 enhancer fragment from the promoter of NRT2.1.We showed that GDS1 promotes NO3-signaling,absorption and assimilation by affecting the expression of multiple NO3-regulatory genes,including Nitrate Regulatory Gene2(NRG2).Interestingly,we observed that gds1 mutants show early leaf senescence as well as reduced NO3 content and N uptake under N-deficient conditions.Further analyses indicated that GDS1 binds to the promoters of several senescence-related genes,including Phytochrome-Interacting Transcription Factors 4 and 5(PIF4 and PIF5)and represses their expression.Interestingly,we found that N deficiency decreases GDS1 protein accumulation,and GDS1 could interact with Anaphase Promoting Complex Subunit 10(APC10).Genetic and biochemical experiments demonstrated that Anaphase Promoting Complex or Cyclosome(APC/C)promotes the ubiquitination and degradation of GDS1 under N deficiency,resulting in loss of PIF4 and PIF5 repression and consequent early leaf senescence.Furthermore,we discovered that overexpression of GDS1 could delay leaf senescence and improve seed yield and N-use efficiency(NUE)in Arabidopsis.In summary,our study uncovers a molecular framework illustrating a new mechanism underlying low-N-induced early leaf senescence and provides potential targets for genetic improvement of crop varieties with increased yield and NUE.