Identification And Analysis Of Candidate Effector Proteins Of Magnaporthe Oryzae

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most destructive diseases and brings enormous economic losses in rice product every year. As a typical model of fungal pathogens, deepen the research on M. oryzae will not only help us build up the theoretical basis to prevention and control of rice blast, but also provide reference to the studies of other pathogens.Bioinformatics analysis of the 851 in-planta-expressed candidate rice blast effectors revealed 31 and 5 candidate proteins were predicted to localize into chloroplast and ERs (or peroxisome), respectively. Twenty of them has been cloned and fusion with the GFP、YFP and RFP protein in plant transient expression vector. The majority of 20 candidate effectors were up-regulated or specific expressed on appressorium stage. We detected 15 candidate effectors signal in tobacco and rice protoplast transient expression system. However, most of the signals were locate at nucleus and membrane, which contradicted with the bioinformatics predicted results. Interestingly, we found one protein (MGG05381) locate at chloroplast and two proteins (MGG03926 and MGG08275) locate at peroxisome, repectively. Through tobacco transient expression tests, no candidate effectors can induce cell death, but 5 proteins (MGG00120, MGG05381, MGG08275, MGG03946, and MGG08994) can suppress BAX induce cell death. Further more, we random check 8 candidate effectors for verification of the protein secrete ability in yeast. Five candidate effectors has been confirmed to be able to secrete out of the cell, and two candidate effectors were not sure (need to be further confirmed) and one candidate effector has no secretive function.In conclusion, three proteins (MGG00120), locate at membrane, and MGG08275\MGG03946 both of them locate at peroxisome) were most likely to be M. oryzae. As they were highly expression on appresorium stage and can suppress BAX induce cell death. To further study the fuction of these three candidate effectors, we intend to knock-out those genes in M. oryzae and successful get the MGG03944 gene knock-out muntant. This study has paved the way for further characterization of the candidate effector faction, and understanding the molecular mechanism of rice-M. oryzae interaction.