Identification of candidate genes for adult plant stripe rust resistance transferred from Aegilops ventricosa 2NvS into wheat via fine mapping and transcriptome analysis

Abstract

Abstract The 2NvS translocation from Aegilops ventricosa, known for its resistance to various diseases, has been pivotal in global wheat breeding for more than three decades. Here we identified an adult plant resistance (APR) gene in the 2NvS segment in wheat line K13-868. Through fine mapping in a segregating near-isogenic line (NIL) derived population of 6,389 plants, the candidate region for the APR gene was narrowed down to between 19.36 Mb and 33 Mb in the Jagger v1.1 genome. Transcriptome analysis in NILs strongly suggested that this APR gene conferred resistance to stripe rust by triggering plant innate immune responses. Two disease resistance-associated genes within the candidate region, TraesJAG2A01G041000 and TraesJAG2A01G046200, exhibited a stronger response to Puccinia striiformis f. sp. tritici (Pst) infection at the adult plant stage than at the seedling stage, indicating that they could be potential candidates for the resistance gene. Additionally, we developed a co-dominant InDel marker, InDel_31.05, for detecting this APR gene. Applying this marker showed that over one-half of the wheat varieties approved in 2021 and 2022 in Sichuan province, China, carry this gene. Agronomic trait evaluation of NILs indicated that the 2NvS segment effectively mitigated the negative effects of stripe rust on yield without affecting other important agronomic traits. This study provided valuable insights for cloning and breeding through the utilization of the APR gene present in the 2NvS segment.