Superior haplotype of TaMPK3-6B is significantly associated with drought survival in wheat: from genome-wide mining to potential breeding application

Mitogen-activated protein kinase (MAPK/MPK) cascades play crucial roles in plant stress responses, but the roles of MPK cascades and their allelic variation in wheat under drought stress remain poorly understood. In this study, we identified 62 wheat MPK genes through a genome-wide search and classified them into subgroups based on conserved motifs and evolutionary analysis. Phylogenetic and gene structure analyses revealed that TEY-type MPKs form a distinct clade in wheat. Expression profiling using public transcriptome datasets and qRT-PCR showed that many TEY-type TaMPK genes, including TaMPK3-6B , are significantly induced by abiotic stresses. We performed haplotype analysis of TaMPK3-6B using resequencing data from 344 wheat accessions and identified three major haplotypes, and TaMPK3-6B-Hap III was significantly associated with enhanced drought survival across multiple cultivars. Moreover, expression of TaMPK3-6B under drought stress was also higher in drought-tolerant cultivars than in drought-sensitive cultivars, supporting its potential involvement in drought adaptation. These results indicate that TEY-type TaMPK genes, particularly TaMPK3-6B , may contribute to drought responses. The drought-associated TaMPK3-6B haplotype identified here is a promising target for functional validation and may facilitate future marker-assisted breeding after functional validation.