Screening And Analysis Of Transcription Factors Induced In Early Infection Stage Of Magnaporthe Oryzae

Rice blast caused by Magnaporthe oryzae is one of the serious diseases which threaten the production of rice.The invasion mechanism of Magnaporthe oryzae has been the study hotspot these years.The early stage of Magnaporthe oryzae interacting with rice plays an important role in the infection cycle of Magnaporthe oryzae Effectors expressed in this stage are important for successfully infection.Transcription factors(TFs)can regulate gene expression.Transcription factors also play an important role in regulating the growth of Magnaporthe oryzae and affecting the pathogenicity of Magnaporthe oryzae.We want to screen the transcription factors highly expressed in the early infection stage and analysis the role of transcription factors regulating the effectors,which can help us to study the mechanism of interaction at transcription level.We chose 486 putative TFs in the Fungal Transcription Factor Database(FTFD)to study.First we did the RT-PCR test and got rid of the 160 TFs which can highly express in the vegetative stage of Magnaporthe oryzae.Next,the remained 326 TFs which can't highly express in the vegetative stage are screened by qRT-PCR.96 TFs were found highly expressed in 12hours after inoculation and 36hours after inoculation.The relative expression level can increase 10 fold at least in 12hai or 36hai compared with the vegetative stage.Among them,22 TFs increased more than 100 folds.17 TFs increased more than 50 folds but less than 100 folds.The rest TFs increased more than 10 folds but less than 50 folds.Then we classified the 96 TFs based on their domains.47 of them belong to Zn2Cys6-type transcription factors.23 of them belong to C2H2-type transcription factors.6 of them belong to HMG-type transcription factors.5 of them belong to Nucleic acid-binding,OB-fold-type transcription factors.4 of them belong to Homeodomain-like-type transcription factors.The number of jumonji-type transcription factors,Zinc finger,CCHC-type transcription factors,Winged helix repressor DNA-binding-type transcription factors and bZIP-type transcription factors are 2.The number of Heteromeric CCAAT factors-type transcription factors,Myb-type transcription factors and Zinc finger,BED-type predicted-type transcription factors are one.To analysis the detailed expression profiles of transcription factors highly expressed in the early infection stage,We finished the 32 TFs expression analysis in 4 hours after inoculation(4hai)?8 hours after inoculation(8hai)?12 hours after inoculation(12hai)?18 hours after inoculation(18hai)?24 hours after inoculation(24hai)?36 hours after inoculation(36hai)?48 hours after inoculation(48hai)?72 hours after inoculation(72hai)and 96 hours after inoculation(96hai)by qRT-PCR.As a result,we found that the expression trend of 25 TFs are low first,then high,then low;7 TFs can express like a wave,high and low for several times.Besides,32 screened TFs has low expression after 48hai.The result states that the expression trend of transcription factors highly expressed in the early infection stage are polytropic.