Aegilops tauschii, a monocotyledonous annual grass, recognized as a pivotal progenitor of modern wheat (Triticum aestivum L.), serves as the D-genome donor in hexaploid wheat. This diploid species (2n = 2x = 14, DD) harbors a substantial reservoir of genetic diversity, particularly in terms of biotic and abiotic stress resistance traits. The extensive allelic variation present in its genome has been increasingly utilized for wheat genetic enhancement, particularly through introgression breeding programs aimed at improving yield potential and stress resilience. Heavy metal ATPases (HMAs), which belong to the P-type ATPase superfamily and are also known as P1B-type ATPases, play a crucial role in transporting heavy metals and maintaining metal ion homeostasis in plant cells. HMAs have been extensively studied in model plants like Arabidopsis thaliana and rice. However, this family has not been reported in A. tauschii. Here, we conducted the genome-wide identification and bioinformatics analysis of the AetHMA gene family in A. tauschii, resulting in the discovery of a total of nine AetHMA members. Among AetHMA genes, six pairs are large-block duplication genes, which mainly occur among the four genes of AetHMA2, AetHMA4, AetHMA8, and AetHMA9. Additionally, there is one pair that consists of tandem duplication genes (AetHMA6: AetHMA7). All AetHMAs can be classified into six groups (I–VI), which are further divided into two branches: the copper subclasses and the zinc subclasses. Initially, A. tauschii was grown in a 1/2 Hoagland nutrient solution and subsequently exposed to four heavy metals: zinc (Zn), copper (Cu), manganese (Mn), and cadmium (Cd). Following this treatment, the expression profiles of nine AetHMA genes were assessed. The results indicated that, under zinc and manganese stress, the HMA family members exhibited enhanced expression in the leaves, whereas the expression of most members in the roots was downregulated. In the roots, except for AetHMA2, AetHMA5, and AetHMA8, the expression levels of other members were upregulated in response to Cd exposure. Furthermore, AetHMA4 diminishes the tolerance of yeast to Mn by increasing the absorption of Mn, while AetHMA8 increases the tolerance of yeast to Cd by reducing the absorption of Cd. This study provides experimental data regarding the function of the AetHMA gene in the transport, regulation, and detoxification of heavy metal elements in A. tauschii.

The APETALA2/ethylene-responsive factor (AP2/ERF) is a well-researched superfamily of plant transcription factors. The APETALA2 (AP2) subfamily is essential for plant growth and development. However, a systematic analysis of the AP2 subfamily in poplar has yet to be conducted. This study identified 29 AP2 genes in the poplar genome, classifying them into three clades—euAP2, euANT, and basalANT based on evolutionary relationships. These genes are distributed across 12 chromosomes and one scaffold. Results from the syntenic analysis suggest that whole-genome duplication events are the primary factors driving the expansion of the AP2 subfamily in poplar. Cis-element analysis reveals that numerous PtAP2 genes possess hormone-related cis-elements. These genes also contain cis-elements linked to plant development and stress responses. PtAP2s from different clades exhibit significantly tissue-specific expression patterns in poplar. Gene expression levels in the euAP2 clade are significantly higher than in the euANT and basalANT clades across various tissues, with basalANT showing the lowest expression. Through RT-qPCR and recombinant Saccharomyces cerevisiae assays under salt stress, it was discovered that the majority of AP2 genes showed a negative response in salt stress regulation in poplar trees. In conclusion, this study offers valuable insights into salt tolerance in poplar trees and the role of AP2 genes under salt stress conditions.