Whole genome identification and expression analysis of ARM gene family in wheat

Wheat is one of the world's major food crops, and its yield and quality are significantly affected by various biotic and abiotic stresses. Armadillo (ARM) repeat proteins regulate plant development, signaling, and stress responses; however, the ARM gene family in wheat remains uncharacterized. In this study, we identified ARM genes from six plant species: Triticum aestivum, Triticum urartu, Aegilops tauschii, Triticum dicoccoides, Arabidopsis thaliana, and Oryza sativa ssp. japonica, totaling 32, 8, 13, 22, 15, and 8 genes, respectively. These genes were classified into three subfamilies (C1-C3). We analyzed their gene structures, conserved motifs, predicted protein properties, and phylogeny. Genomic analyses were conducted to investigate gene family expansion and evolutionary selection. Cis-acting element analysis and RNA-seq were used to assess stress responsiveness, which was further validated by qRT-PCR. Genomic analyses indicated that polyploidy-driven segmental duplications expanded the wheat ARM gene family, with purifying selection dominating its evolution. Cis-acting element analysis revealed the molecular basis for TaARM gene responses to abiotic stress. RNA-seq and qRT-PCR analyses demonstrated distinct response characteristics among TaARM members. Specifically, TaARM13 and TaARM22 responded to biotic stresses (powdery mildew and stripe rust); TaARM18 was induced by powdery mildew and low-temperature stress; and TaARM26 was specifically upregulated by low-temperature stress. These results suggest that different members of the TaARM gene family play unique and specific roles in coping with various stresses. Future research integrating multi-omics data and molecular validation will support the breeding of stress-resilient wheat varieties.