Abstract
AINTEGUMENTA-LIKE6 (AIL6) is a transcription factor specifically expressed in embryos. It is a key to improving peony regeneration through tissue culture. Based on transcriptomic data from our previous research and the published genome data of Paeonia ostii, we identified the PoAIL6 gene associated with somatic embryogenesis (SE) in Paeonia ostii 'Fengdan'. Structural and phylogenetic analyses were conducted on the PoAIL6-encoded protein, and its expression pattern across tissues and embryo developmental stages were explored using real-time quantitative PCR. Our results revealed that PoAIL6 contained two AP2 conserved domains and the characteristic motif of AIL6 genes. Phylogenetic analysis revealed that the PoAIL6 gene has similarity to grape (Vitis vinifera) and cocoa (Theobroma cacao). PoAIL6 exhibited the highest expression during early embryonic development, with expression levels gradually decreasing throughout SE progression. It was most highly expressed in peony seeds and showed relatively high expression in callus tissue. This study underscores the pivotal role of PoAIL6 in the early SE and lays a playground for elucidating its molecular mechanisms, supporting the development of efficient and stable regeneration and transformation systems in peony.