Research On Mechanism Of Non-host Resistance In Arabidopsis

Non-host resistance, manifesting at species level, is an important type of plant disease resistance. It is strong, long-lasting and effective against a broad spectrum of plant pathogens, protecting plants from infection of most potential pathogens. So understanding the molecular mechanism of non-host resistance will provide a new strategy to control plant disease. AtPEN1 is a very important component of non-host resistance and knocking out of AtPEN1 will decrease Arabidopsis'non-host resistance to Bgh(Blumeria graminis f. sp hordei). AtPEN1 encodes plasma located AtSYP121, which belongs to SNARE(Soluble N-ethyl-maleimide-sensitive fusion protein attachment protein receptor)family. It has been proved that AtPEN1 mediate the formation of papillae in the pathogen invasion site by regulating the vesicle traffic, which is also a negative regulator of signal pathway. But we still know very little about the mechanism of how AtPEN1 regulates the vesicle traffic and signal pathway.S-nitrosylation which mediates by nitric oxide is an important post-translational modification. It is a swift, reversible and high specific way to mediate signal transduction by regulating the activity, stability and location of proteins. Because NO production is one of the earliest responses during pathogen-plant interaction, we suppose that the loss function of AtPEN1 may affect the SNO level of the cell.By measuring the SNO level of Atpen1-1 and wild type using Saville-Griess assay, we found that SNO level decreased in Atpen1-1,which suggests that lose of AtPEN1 function evoke the changes of S-nitrosylational modification. By assaying the transcriptional level and the enzyme activity of AtGSNOR (S-nitrosoglutathione reducase), we haven't found any difference. So maybe the changes of SNO level in Atpen1-1 were caused by other unknown regulation mechanism. We have identified two proteins which have different S-nitrosylational modification between Atpen1-1 and wild type. They are cobalamin-independent methionine synthase and malate dehydrogenase.We have obtained a mutant population by EMS mutagenesis using 35SGFP-PEN1 seeds and try to find some mutant associated with AtPEN1 function.