Abstract:
Objective This study aimed to analyze the chromosomal localization of the AP2/ERF(APETALA2/Ethylene - responsive Element Binding Factor) gene family in Xanthoceras sorbifolium Bunge, the gene structure, the cis-acting elements in the promoter, and the expression patterns under salt mist stress, providing a reference for exploring the role of XsAP2/ERF under salt mist stress.
Methods AP2/ERF gene family members were systematically identified using bioinformatics tools (NCBI database, GSDS2.0, MEGA7.0) based on the X. sorbifolium genome. Transcriptome sequencing was performed on leaves of X. sorbifolium seedlings subjected to 0-, 2-, and 4-day salt spray stress (saturated NaCl solution) to investigate AP2/ERF gene expression dynamics.
Results (1) A total of 145 AP2/ERF genes were identified in the whole genome of X. sorbifolium, unevenly distributed on 15 chromosomes.(2) Through phylogenetic and domain analysis, the AP2/ERF gene family of X. sorbifolium was divided into three subfamilies: AP2 (21 genes), ERF (119 genes), and RAV (5 genes). A total of 10 conserved motifs were identified, and only motif 1 was the common motif of this gene family. Moreover, 90 genes contained no introns.(3) A total of 19 types and 1930 cis-acting elements were found in the promoter region of AP2/ERF genes of X. sorbifolium, related to abiotic stress, growth and development, and phytohormone response. Among them, ABA-responsive elements were the most abundant (432). Interaction network analysis revealed four proteins with strong predicted interactions with AP2/ERF transcription factors.(4) Ten AP2/ERF genes of X. sorbifolium (XsAP2/ERF2, XsAP2/ERF22, XsAP2/ERF23, XsAP2/ERF27, XsAP2/ERF48, XsAP2/ERF103, XsAP2/ERF111, XsAP2/ERF122, XsAP2/ERF128) were significantly and continuously upregulated during salt mist stress.
Conclusion The XsAP2/ERF gene family plays an important role in the response of X. sorbifolium to salt mist stress. These findings provide a theoretical foundation for clarifying the biological functions of XsAP2/ERF genes and identifying salt-tolerant genetic resources in X. sorbifolium.