Somatic embryogenesis is a crucial biotechnological approach for effectively addressing garlic variety degeneration and improving yield and quality. Previous studies have demonstrated that the long noncoding RNA 125175 (lncRNA125175) is specifically induced and expressed during somatic embryogenesis, and may act as an endogenous target mimic of AsmiR393h to participate in the regulation of somatic embryogenesis. On this basis, the present study systematically elucidated the functions of the lncRNA125175/AsmiR393h/AsTIR1 regulatory module and its upstream transcriptional mechanism. First, transient expression assays in tobacco leaves and protoplast experiments in garlic suggested that lncRNA125175 served as a competing endogenous RNA (ceRNA) to sequester AsmiR393h, thereby attenuating its post-transcriptional cleavage of the target gene AsTIR1. Promoter analysis revealed that all core components of this module contain auxin cis-acting elements, and the promoter activities of lncRNA125175 and AsTIR1 are significantly induced by exogenous auxin, suggesting that this ceRNA network is precisely regulated by auxin signaling. Further weighted gene co-expression network analysis identified the auxin response factor AsARF16 as a key upstream regulator. Yeast one-hybrid and two-hybrid assays indicated that AsARF16 can directly bind to the promoter of lncRNA125175, and interact with the transcription factor AsWRKY31 and the auxin signaling factor AsIAA33 to form a transcriptional activation complex. In conclusion, this study uncovers a cascade pathway from auxin signal perception (the AsARF16 complex) to transcriptional activation (lncRNA125175), followed by post-transcriptional ceRNA regulation. It systematically clarifies the molecular mechanism underlying its precise regulation of garlic somatic embryogenesis, providing a critical theoretical basis for the targeted improvement in garlic regeneration efficiency and genetic transformation systems.

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