Characterization of APETALA2/Ethylene Responsive Factor Gene Family and Their Responses to Abiotic Stress in Pineapple (Ananas comosus)

AP2/ERF (APETALA2/Ethylene Responsive Factor) transcription factors, a class of plant-specific transcription factors, play a pivotal role in plant growth, development, metabolism, and stress response. The pineapple (Ananas comosus (L.) Merr.), a perennial fruit, belongs to the Bromeliaceae family. It is an economically important crop worldwide, which is consumed as fresh fruit, canned fruit, a fiber source, and even pharmaceutical raw material. We identified 75 AcoAP2/ERF genes in the pineapple genome, with four manually curated. They were distributed evenly on 23 chromosomes, except on LG20 and LG23. Sequence lengths, molecular weights, and intron numbers were diverse. The majority of pineapple AcoAP2/ERF genes were localized in nuclear while seven AcoERFs were located in mitochondrial or chloroplast. All pineapple AcoAP2/ERF genes possess an AP2 domain and are divided into 10 clades. Most originate from whole-genome or segmental duplication instead of transposon events. Utilizing pineapple calluses as experimental material, qRT&ndash:PCR analysis revealed that the expression of the majority of AcoAP2/ERF genes was induced in response to abscisic acid (ABA), gibberellic acid (GA), ethylene (ET), and naphthalene acetic acid (NAA). In this study, we cloned the promoter sequence of the AcoERF24 gene and divided it into three fragments to construct individual vectors. These vectors were subsequently introduced into Arabidopsis thaliana for &beta:-glucuronidase (GUS) activity analysis, revealing variations in activity levels among the different fragments. This study not only deepens our understanding of the AcoAP2/ERF genes family in olives but also provides an important basis for subsequent studies on the regulation of AcoERF24 gene expression and biological functions.