FgHtf1 Regulates Global Gene Expression During Conidiation-related Mophogenesis

Fusarium graminearum is an important plant-pathogenic fungus and the major cause of all classes of wheat and other small grains.The homeobox gene family(Hox)transcription factors regulate numerous pathways during developmental and normal cellular processes.The homeodomain is greatly conserved through evolution structurely and functionly.Recently significant research effort has been spent to elucidate the exact mechanisms on functional specificity of the Hox proteins.Our previews study showed that a conserved homeobox transcription factor FgHtfl required for phialide development and conidiogenesis in Fusarium graminearum.Interestingly although the production of spores was severely reduced,the other phenotypes such as vegetative growth,sexual reproduction and pathogenicity were not affected.Thus the FgHtflwas determined as a specifie regulator for eonidiogenesis in F.graminearum.Conidia are the main way of dispersal for a variety of pathogenic fungi and play an important role in animal and plant disease epidemics.To further understand the regulatory mechanisms governed by FgHtfl and finding out the targeted genes,a chromatin immunoprecipitation followed by massively parallel DNA sequencirtg(ChIP-seq)was used to identify the direct targeted genes of FgHtf1.Combined with a RNAseq data we did before,we got a total 186 potential binding peaks including 142 directly regulated genes,resulting in the prediction of two DNA binding motif TAAT and CTTGT.Of particular note,the FgHtfl targeted genes included some reported conidiation related genes.Beside,FgHtfl itself was a target,suggesting an autxoregulation control point.Moreover,functional characterization of a target gene FgCon7,we found ?FgCon7 can only produce conidia by the tip the hyphae,which is simlar with ?FgHtf1.Take all together,our study found some direct target genes of FgHtfl,and it will provide more theoretical basis for studying Hox genes of other fungi.