A novel nitrogen-dependent gene associates with the lesion mimic trait in wheat

Using bulk segregant analysis (BSA) coupling with RNA-seq and DNA markers identified a potentially novel nitrogen-dependent lesion mimic gene Ndhrl1 on 2BS in wheat. Lesion mimic (LM) refers to hypersensitive reaction-like (HRL) traits that appear on leaf tissue in the absence of plant pathogens. In a wheat line P7001, LM showed up on the leaves under the 0 g nitrogen (N) treatment, but disappeared when sufficient N was supplied, suggesting that LM is N-responsive and N dosage dependent. Using BSA strategy together with RNA-seq and DNA markers, we identified an N-dependent LM gene (Ndhrl1) and mapped it to the short arm of chromosome 2B using an F₅ recombinant inbred population developed from the cross of P7001 × P216. The putative gene was delimited into an interval of 8.1 cM flanked by the CAPS/dCAPS markers 7hrC9 and 7hr2dc14, and co-segregated with the dCAPS marker 7hrdc2. This gene is most likely a novel gene for LM in wheat based on its chromosomal location. Further analysis of RNA-seq data showed that plant-pathogen interaction, nitrogen metabolism, zeatin biosynthesis and plant hormone signal transduction pathways were significantly differentially expressed between LM and non-LM lines.