Suppression of edr2-mediated powdery mildew resistance, cell death and ethylene-induced senescence by mutations in ALD1 in Arabidopsis  

作　　者：Haozhen Nie Yingying Wu Chunpeng Yao Dingzhong Tang 

机构地区：[1]State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Journal of Genetics and Genomics》2011年第4期137-148,共12页遗传学报（英文版）

基　　金：supported by the grants from National Basic Research Program of China (973 Program, 2011CB100700);the National Transgenic Program of China (No. 2009ZX08009-042B);the National Natural Science Foundation of China (No. 30771168).

摘　　要：EDR2 is a negative regulator of the defense response and cell death in Arabidopsis.Loss-of-function of EDR2 leads to enhanced resistance to powdery mildew.To identify new components in the EDR2 signal transduction pathway,mutations that suppress edr2 resistant phenotypes were screened.Three mutants,edts5-1,edts5-2 and edts5-3（edr two suppressor 5）,were identified.The EDTS5 gene was identified by map-based cloning and previously was shown to encode an aminotransferase（ALD1）.Therefore we renamed these three alleles ald1-10,ald1-11 and ald1-12,respectively.Mutations in ALD1 suppressed all edr2-mediated phenotypes,including powdery mildew resistance,programmed cell death and ethylene-induced senescence.Accumulation of hydrogen peroxide in edr2 was also suppressed by ald1 mutation.The expression of defense-related genes was up-regulated in the edr2 mutant,and the up-regulation of those genes in edr2 was suppressed in the edr2/ald1 double mutant.The ald1 single mutant displayed delayed ethylene-induced senescence.In addition,ald1 mutation suppressed edr1-mediated powdery mildew resistance,but could not suppress the edr11edr2 double-mutant phenotype.These data demonstrate that ALD1 plays important roles in edr2-mediated defense responses and senescence,and revealed a crosstalk between ethylene and salicylic acid signaling mediated by ALD1 and EDR2.EDR2 is a negative regulator of the defense response and cell death in Arabidopsis.Loss-of-function of EDR2 leads to enhanced resistance to powdery mildew.To identify new components in the EDR2 signal transduction pathway,mutations that suppress edr2 resistant phenotypes were screened.Three mutants,edts5-1,edts5-2 and edts5-3（edr two suppressor 5）,were identified.The EDTS5 gene was identified by map-based cloning and previously was shown to encode an aminotransferase（ALD1）.Therefore we renamed these three alleles ald1-10,ald1-11 and ald1-12,respectively.Mutations in ALD1 suppressed all edr2-mediated phenotypes,including powdery mildew resistance,programmed cell death and ethylene-induced senescence.Accumulation of hydrogen peroxide in edr2 was also suppressed by ald1 mutation.The expression of defense-related genes was up-regulated in the edr2 mutant,and the up-regulation of those genes in edr2 was suppressed in the edr2/ald1 double mutant.The ald1 single mutant displayed delayed ethylene-induced senescence.In addition,ald1 mutation suppressed edr1-mediated powdery mildew resistance,but could not suppress the edr11edr2 double-mutant phenotype.These data demonstrate that ALD1 plays important roles in edr2-mediated defense responses and senescence,and revealed a crosstalk between ethylene and salicylic acid signaling mediated by ALD1 and EDR2.

关 键 词：ALD1 Ambidopsis Defense signaling EDR2 Powdery mildew Salicylic acid 

分 类 号：S512.103.4[农业科学—作物学] Q255[生物学—细胞生物学]