Study On The Mechanism Of Wheat CHD3 Protein TaCHR729 Regulating Powdery Mildew Resistance

Wheat is a grain crop that is widely cultivated in the world,which provide energy and protein for more than fourth of people in the world.As a worldwide disease,wheat powdery mildew caused by the fungal pathogen Blumeria graminis f.sp.Tritici?Bgt?has been getting worse in recent years.Therefore overcoming the wheat powdery mildew disease resistant mechanism has great significance.The infection of wheat Bgt begins with the germination of its conidia,which is regulated by the wax signal of plant cuticle.In this study,the homologous cloning method was used to obtain the encoding gene TaKCS6 of wheat 3-KETOACYL-CoA SYNTHASE?TaKCS6?.The silencing of TaKCS6 in wheat leaves by virus-induced gene silencing resulted in the decrease of cuticular wax in wheat leaves and the inhibition of the germination of Bgt.We used the native promoter regions of TaKCS6 genes as baits though Yeast one-hybrid?Y1H?to screen wheat cDNA library obtain the wheat transcription factor TaKPAB1.Y1H and Chromatin immunoprecipitation?ChIP?confirmed that TaKPAB1 directly binds to the TaKCS6 promoter and activates TaKCS6gene transcription.The wheat CHD3 protein TaCHR729 was screened by Yeast two-hybrid?Y2H?using TaKPAB1 as bait.The interaction between TaKPAB1 and TaCHR729 was confirmed by Y2H and Co-immunoprecipitation?Co-IP?.The virus-induced gene silencing of TaKPAB1 and TaCHR729 in wheat leaves resulted in the decrease of histone modification of H3K4m3 in the promoter region of TaKCS6 gene,the weakening of gene transcription,the reduction of cuticular wax in wheat leaves,and the inhibition of the germination of conidia in wheat.The wax changes and chemical spraying experiments confirmed that the very-long-chain aldehydes with a chain length above C₂₄as the wax signals of the TaCHR729-TaKPAB1-TaKCS6 pathway for stimulating Bgt germination.Therefore,our study revealed that transcription factors regulated the biosynthesis of cuticular wax by recruiting chromatin remodeling factors and affected the germination of Bgt.The research results provide a new theory and thinking for wheat disease resistance breeding.