The Function Of Transcription Factor TF13894 In Regulating AvrPik Expression Of Rice Blast Fungus,Magnaporthe Oryzae

Rice is one of the most important crops in the world and rice blast disease,caused by Magnaporthe oryzae is a major disease of rice,which can cause serious impact on the security and stability of world food production.The interaction betweenrice andM.oryzae has become a model system to study the mechanism of interaction between plant and pathogen.Transcription factors are important in regulation of gene expression and critical for the blast fungal growth and development.However,whether transcription factors involved in regulation of interaction between rice blast fungus and host during the early infection stage remains unclear.Our previous study identified 96 TFs which highly expressed during the early stage of the infection by qRT-PCR.24 TF genes have been knocked out by using homologous recombination.24 TF knockout mutants were used to infect 18 rice blast resistance genes monogenic-lines and we found that ΔTF13894mutantrestored fungal virulence on two monogenic genes rice lines,Pi-7 and Pikp,indicating that TF13894 may be involved in regulatingthe expression of corresponding avirulence effector proteins in M.oryzae.Based on these results,we use gene knockout,phenotype test,gene expression and localization and yeast one hybrid to test whether the expression and function of AvrPik is regulatedby transcription factor TF13894in rice blast fungus.As AvrPik has 5 different recognition-function halpotype(A-E)and the previous background strain 98-06 only encode AvrPik-A and-D,to determain the regulation of TF13894 to AvrPik-A and-D,the strain R88002 without encoding any AvrPik allele was used as new background strain to transforme with AvrPik-D and AvrPik-A respectively.And then the TF13894 was knocked out fromR88002-AvrPik-D and R88002-AvrPik-A strain respectively.Rice spraying assay showed TF 13894 deletion makeAvrPik-D/R88002 strain regain the virulence to pi7 rice,but AvrPik-A/R88002 still keep avirulence to Pi-1 和 Pikh rice.Fluorescence observation and transcription activity test showed TF 13894 localize to nucleus and has transcription activity,which indiacted that TF13894 is a typical transcription factor.The result of yeast one hybrid indicated that TF13894 only interacted with AvrPik-D promoter,but not AvrPik-A.In conclusion,TF13894 of Magnaporthe oryzae can regulat the expression of AvrPik-D to affect the recognition between AvrPik-D and Pi-7 but can not regulate AvrPik-A expression..