Two functional CC‐NBS‐LRR proteins from rye chromosome 6RS confer differential age‐related powdery mildew resistance to wheat

Abstract

SummaryRye (Secale cereale), a valuable relative of wheat, contains abundant powdery mildew resistance (Pm) genes. Using physical mapping, transcriptome sequencing, barley stripe mosaic virus‐induced gene silencing, ethyl methane sulfonate mutagenesis, and stable transformation, we isolated and validated two coiled‐coil, nucleotide‐binding site and leucine‐rich repeat (CC‐NBS‐LRR) alleles, PmTR1 and PmTR3, located on rye chromosome 6RS from different triticale lines. PmTR1 confers age‐related resistance starting from the three‐leaf stage, whereas its allele, PmTR3, confers typical all‐stage resistance, which may be associated with their differential gene expression patterns. Overexpression in Nicotiana benthamiana showed that the CC, CC‐NBS, and CC‐LRR fragments of PMTR1 induce cell death, whereas in PMTR3 the CC and full‐length fragments perform this function. Luciferase complementation imaging and pull‐down assays revealed distinct interaction activities between the CC and NBS fragments. Our study elucidates two novel rye‐derived Pm genes and their derivative germplasm resources and provides novel insights into the mechanism of age‐related resistance, which can aid the improvement of resistance against wheat powdery mildew.