The TIFY family, a plant-specific group of transcription factors, plays critical roles in regulating growth, development, and stress responses. This study aimed to clone TaTIFY11c-4A in wheat, validate its genetic effects, and provide a theoretical basis for high-yield molecular breeding of wheat.

The wheat cultivar Hanxuan 10 was used to clone TaTIFY11c-4A and allelic variations were detected in germplasms. The tissue-specific expression patterns of TaTIFY11c-4A and its responses to various hormones and stresses were analyzed via quantitative real-time PCR (qRT-PCR). The subcellular localization of TaTIFY11c-4A was determined through transient expression in tobacco. A molecular marker targeting the polymorphic site in TaTIFY11c-4A was developed to assess the genotypes in the natural population, and association analysis was performed to evaluate the correlations between the genotypes and phenotypes. Additionally, the spatial and temporal distribution of different genotypes were analyzed. Synergistic effects of TaTIFY11c-4A and TaSRL1-4A haplotypes were explored to identify superior genotype.

TaTIFY11c-4A was successfully cloned, comprising three exons and two introns, encoding a 198-amino acid protein with conserved TIFY and Jas domains. TaTIFY11c-4A is expressed in roots, root bases and leaves at the seedling stage, and highly expressed in roots and leaves at the booting stage. There are multiple cis-acting elements related to hormone responses, stress adaptation, and endosperm development in the promoter of TaTIFY11c-4A. Its expression responds to plant hormones (ABA, IAA, MeJA) and abiotic stresses (drought, high salinity, low and high temperature). A SNP (G/A) was identified in its promoter at -405 bp. A molecular marker was developed based on the SNP and association analysis revealed significant correlations between TaTIFY11c-4A alleles and plant height, thousand grain weight under multiple environments such as drought and high temperature, and root depth at tillering stage. Compared with genotype SNP-G, wheat germplasms carrying the SNP-A allele exhibited shorter plants, higher thousand grain weight, and shallower roots at tillering stage, and have been positively selected in the wheat breeding process. TaTIFY11c-4A-SNP-A and TaSRL1-4A-SNP-C genotypes synergistically reduced plant height and enhanced thousand grain weight.

TaTIFY11c-4A encodes a nuclear-localized JAZ protein. It is expressed in various tissues of wheat and involved in responses to ABA, IAA, MeJA, as well as abiotic stresses such as drought, extreme temperature, and high salinity. The TaTIFY11c-4A-SNP is associated with plant height and thousand grain weight under multiple environments, and root depth. SNP-A allele has been positively selected in the wheat breeding process. The superior genotypes and combinations of TaTIFY11c-4A and TaSRL1-4A provide genetic resources for breeding high-yield and stress-resistant wheat cultivars.