Study On The Function Of Inhibiting Host Methylation By P6 Protein Encoded By Tomato Chlorosis Virus

Tomato chlorosis virus(ToCV),was severely epidemic to damage Solanaceae crops such as tomata worldwidely.ToCV rendered chlorosis,smaller and asymmetrial coloring of fruits,the yield and commodity loss in infected corps.The pathogenetic determinants and its pathogenicity mechanims remained unclear.Uncovered the pathogenetic mechanisms would scientifically contributed to uncover the potential threaten of ToCV against Solanacea crops.The heterologous expression vector pGR107::P6 constructed using homologous recombination based on Potato virus X(PVX)c DNA infectious clone vector pGR107.pGR107::P6 was transferred into Nicotiana benthamiana wild type(WT)by Agrobacteria-mediated method.The infected plants shown no dwarf,and severely mottle and abnomal but no necrosis in leaves.Expressing P6 protein could relatively enhance PVX genomic RNA accumulation,and induce remarkable up-regulation of Bip,HSP90-2 and b ZIP60,the key genes involving endoplasmic reticulum(ER)stress.The pGR107::P6 vector was transferred into N.benthamiana 16 C by Agrobacteria-mediated method.Expressing P6 protein in N.benthamiana 16 C,enhanced the genome RNAs of PVX at 6dpi,and the ER stucture of N.benthamiana 16 C ER body was not changed,and no ER body appeared.The P6 gene was expressed in N.benthamiana transgenic line 16-TGS using PVX vector.The mosaic symptoms were appeared in new-borned leaves.And the green fluorescence was existing in inoculated leaves,the expressing of GFP gene was also verified by Western blottingting.The endonuclease Mcr BC,which selectively digests methylated DNA,was used to digested genomic DNA of N.benthamiana transgenic line 16-TGS.The result shown the digesting genomic DNA level of Mrc BC inhibited by P6 protein.The key genes involving DNA methylation expressing profile shown the DRM2,CMT3 and AGO4 were relatively downregulated.Taken together,P6 protein possessed capacity to inhibit the host DNA methylation.