New progress in plant disease resistance mechanism

Powdery mildew widely exists in nature, can infect many kinds of crops and economic crops, and has brought serious losses to agricultural production in the world With Arabidopsis as a model plant, scientists have made some progress in the study of the mechanism of resistance to powdery mildew Many key genes, including EDR2, have been found to regulate resistance to powdery mildew In Arabidopsis, EDR2 mutants showed increased resistance to powdery mildew and cell death induced by powdery mildew, while EDR2 mutants also showed increased ethylene induced senescence Tang Dingzhong research group, Institute of genetics and developmental biology, Chinese Academy of Sciences, selected some EDR2 suppressor mutants by genetic methods One of them, sr1-4d, can inhibit various phenotypes of EDR2 mutant, including powdery mildew resistance, powdery mildew induced cell death and enhanced ethylene induced senescence Sr1 is a calmodulin binding transcription factor Sr1-4d mutant is a functional acquired mutant Its mutation is located in the calmodulin binding domain of Sr1, resulting in a functional acquired protein By inoculating different strains of sr1-4d, it was found that sr1-4d showed increased susceptibility to a variety of pathogens, including various saprophytic and living vegetative growth types of fungi and bacteria, and sr1-4d accumulated a low level of salicylic acid, while the functional loss mutant Sr1 showed the opposite phenotype to sr1-4d Through EMSA and chip experiments, it was found that Sr1 inhibited the expression of ndr1 and EIN3 genes which play an important role in disease resistance and ethylene response by directly combining the promoters of ndr1 and EIN3 Further study showed that the ndr1 mutation could inhibit the resistance phenotype of Sr1, while EIN3 could inhibit the senescence phenotype induced by Sr1 ethylene These results suggest that Sr1 can fine regulate plant disease resistance and ethylene induced senescence by regulating ndr1 and EIN3 This study is the first to find the direct regulatory effect of Sr1 on ndr1 and EIN3, and to find that Sr1 is a key intersection of salicylic acid signaling pathway and ethylene signaling pathway at the transcriptional level The study was published online in plant physiology in February 2012 (DOI: 10.1104 / pp.111.192310) Nie haozhen, a doctoral student in the research group of Tang Dingzhong, is the first author of this paper The research was supported by the Ministry of science and technology, the National Natural Science Foundation of China and the transgenic project.