Phenolamide(PA)metabolites play important roles in the interaction between plants and pathogens.The putrescine hydroxycinnamoyl transferase genes Os PHT3 and Os PHT4 positively regulate rice cell death and resistance ...Phenolamide(PA)metabolites play important roles in the interaction between plants and pathogens.The putrescine hydroxycinnamoyl transferase genes Os PHT3 and Os PHT4 positively regulate rice cell death and resistance to Magnaporthe oryzae.The b ZIP transcription factor APIP5,a negative regulator of cell death and rice immunity,directly binds to the Os PHT4 promoter to regulate putrescine-derived PAs.Whether other hydroxycinnamoyl transferase(HT)genes also participate in APIP5-mediated immunity remains unclear.Surprisingly,we find that genes encoding agmatine hydroxycinnamoyl transferases Os AHT1 and Os AHT2,tryptamine hydroxycinnamoyl transferases Os TBT1 and Os TBT2,and tyramine hydroxycinnamoyl transferases Os THT1 and Os THT2,responsible for the biosynthesis of polyamine-derived PAs are all up-regulated in APIP5-RNAi transgenic plants compared with segregated wild-type rice.Furthermore,both Os AHT1/2 and Os TBT1/2 are induced during M.oryzae infection,showing expression patterns similar to those previously reported for Os THT1/2 and Os PHT3/4.Transgenic plants overexpressing either Os AHT2-GFP or Os TBT1-GFP show enhanced resistance against M.oryzae and accumulated more PA metabolites and lignin compared with wild-type plants.Interestingly,as demonstrated for Os PHT4,APIP5 directly binds to the promoters of Os AHT1/2,Os TBT1/2,and Os THT1/2,repressing their transcription.Together,these results indicate that the HT genes are common targets of APIP5 and that PAs play critical roles in rice immunity.展开更多
基金supported by grants from the National Natural Science Foundation of China (32161143009, 31822041 and 31972225) to Y.N.the National Natural Science Foundation of China (U20A2021) to R.W.the National Natural Science Foundation of China (31801692) to F.Z
文摘Phenolamide(PA)metabolites play important roles in the interaction between plants and pathogens.The putrescine hydroxycinnamoyl transferase genes Os PHT3 and Os PHT4 positively regulate rice cell death and resistance to Magnaporthe oryzae.The b ZIP transcription factor APIP5,a negative regulator of cell death and rice immunity,directly binds to the Os PHT4 promoter to regulate putrescine-derived PAs.Whether other hydroxycinnamoyl transferase(HT)genes also participate in APIP5-mediated immunity remains unclear.Surprisingly,we find that genes encoding agmatine hydroxycinnamoyl transferases Os AHT1 and Os AHT2,tryptamine hydroxycinnamoyl transferases Os TBT1 and Os TBT2,and tyramine hydroxycinnamoyl transferases Os THT1 and Os THT2,responsible for the biosynthesis of polyamine-derived PAs are all up-regulated in APIP5-RNAi transgenic plants compared with segregated wild-type rice.Furthermore,both Os AHT1/2 and Os TBT1/2 are induced during M.oryzae infection,showing expression patterns similar to those previously reported for Os THT1/2 and Os PHT3/4.Transgenic plants overexpressing either Os AHT2-GFP or Os TBT1-GFP show enhanced resistance against M.oryzae and accumulated more PA metabolites and lignin compared with wild-type plants.Interestingly,as demonstrated for Os PHT4,APIP5 directly binds to the promoters of Os AHT1/2,Os TBT1/2,and Os THT1/2,repressing their transcription.Together,these results indicate that the HT genes are common targets of APIP5 and that PAs play critical roles in rice immunity.
