Screening and functional characterization of candidate resistance genes to powdery mildew fromDasypyrum villosum#4in a wheat line Pm97033

Key message Three genes designatedDvLox,Pm21#4, andPm21#4-Hidentified in a wheat-Dasypyrum villosum#4T6V#4S center dot 6DL translocation line Pm97033 conferred wheat for powdery mildew resistance. Powdery mildew (PM) caused byBlumeria graminisf. sp.tritici(Bgt) is one of the most devastating diseases in wheat. To date, only a few genes conferring resistance to wheat PM are cloned.Dasypyrum villosumis a wild relative of wheat, which providesPm21conferring wheat immunity to PM. In this study, we obtained many differentially expressed genes (DEGs) from a wheat-D.villosum#4T6V#4S center dot 6DL translocation line Pm97033 using RNA-sequencing. Among them, 7 DEGs associated with pathogen resistance were up-regulated in front ofBgtinfection. Virus-induced gene silencing and transformation assays demonstrated that two of them,DvLoxandPm21#4encoding a lipoxygenase and a encoding coiled-coil/nucleotide-binding site/leucine-rich repeat resistance protein, conferred wheat PM resistance. The transgenic wheat plants expressingDvLoxenhanced PM resistance, and the transgenic wheat plants expressingPm21#4showed PM immunity. ThePm21#4-silenced Pm97033 plants by the cluster regularly interspaced short palindromic repeats-associated endonuclease (CRISPR/Cas9) system were susceptible to PM. Thus,Pm21#4is a key gene contributing PM immune resistance in Pm97033. Constitutively expression ofPm21#4-H, which is silenced in Pm97033 andD. villosum#4, endowed a PM-susceptible wheat variety Fielder with PM immune resistance.