Study On The Synergism Of DNA Methyltransferase PoDim2 And Two Histone Methylation Related Proteins In Magnaporthe Oryzae

The rice blast disease caused by the ascomycete fungus Magnaporthe oryzae(syn.Pyricularia oryzae)is a serious threat to global food security.To date,breeding of disease-resistant varieties carrying different resistance genes is still the most economical and effective strategy for controlling rice blast disease.However,the complicated population and rapid mutation of avirulence(AVR)genes of the fungus tremendously restricts the persistently effective diseases management.Further study on molecular mechanism underlying the rapid mutation is of great scientific and practical importance.A large amount of the transposable elements(TEs)in the genome are closely associated with the rapid mutation of the fungal AVR genes,however,the regulatory mechanism for TE mobilization and its relationship to the fast variation of AVR genes is not clear yet.Recently,DNA methylation has been proved to play a role in regulating the transcriptional activity rather than the mobilization of TEs in M.oryzae,indicating that the epigenetic regulation of TE mobilization is likely more complex than expected.Therefore,in this study,we will apply functional genomics and epigenetic approaches to further explore the regulatory mechanism for TE mobilization in M.oryzae,through analyzing the interrelation between DNA methylation and histone methylation,as well as their potential reciprocal action on the regulation of TE mobilization.This study might provide new theoretical basis for understanding the rapid mutation mechanism of AVR genes in the rice blast fungus.In this study,we investigated the synergistic effect of DNA methylation and histone methylation by functionaly analyzing the role of the DNA methyltransferase MoDim2 and histone methyltransferase MoKmt1,as well as the histone demethyltransferase MoLid2.Our results demonstrated that both MoDim2 and MoKmt1 were involved in the mycelial growth and response to different stress,including the oxidative and cell wall stress,although the role of MoDim2 in fungal growth was much weaker than that of MoKmt1.Further studies showed that MoDim2 and MoKmt1 may not act synergistically to promote fungal growth,the stress response,conidiation and pathogenicity.While MoDim2 and MoLid2 may synergistically participate in fungal growth-and the response to cell wall stress.Besides,conidiation in ΔModim2ΔMolid2 mutant was dramatically reduced by comparing with either the wild type or ΔModim2,suggesting a role of MoLid2 in conidiogenesis of M.oryzae.These results might provide a good theoretical bases for understanding the functional mechanism and the synergistic roles of DNA methylation and histone methylation in M oryzae.