Regulation Of ADC And Putrescine Biosynthesis By Transcription Factors NAC72 And ABF2 Of Poncirus Trifoliata

In our previous study,PtrNAC72 and PtrABF2 binding to the promoter of ADC were identified by yeast one-hybrid screening.On the basis of this work,Arabidopsis mutant nac72 and abf2 were used to analyze their function in the regulation of ADC expression and putrescine synthesis.The main results are as follows:1.Electrophoretic mobility shift assay(EMSA)demonstrated that PtrNAC72 can interact with the promoter of PtADC.The expression level of AtADC and the content of putrescine in nac72 mutant were higher than those of wild type,suggesting that NAC72 played a negative role in the regulation of ADC.2.Dehydration,drought and cold treatment of nac72 mutant demonstrated that the stress tolerance of mutant was stronger than that of wild type,further demonstrating that NAC72 is a negative regulator.3.We found that the ADC expression level was increased and putrescine in nac72 mutant was accumulated than wild type after dehydration treatment.So we used D-arginine to treat the mutant,and found stress tolerance of mutant was inhibited,indicating that PtrNAC72 might palyed a negative role by regulating the synthesis of putrescine in stress tolerance.4.The phenotype of Arabidopsis abf2 after cold and drought treatment showed that the stress tolerance of mutant was decreased,demonstrating that ABF2 was possibly a positive regulator in drought.