A bZIP transcription factor LlbZIP11 targets LlWOX11 to inhibit bulbil formation in Lilium lancifolium Thunb

Abstract

Bulbil propagation constitutes the primary natural reproductive strategy of Lilium lancifolium Thunb. Our previous study demonstrated that LlWOX11 plays a crucial role in bulbil formation in L. lancifolium. However, the regulatory mechanism underlying LlWOX11-mediated bulbil formation remains poorly understood. In this study, the promoter region of LlWOX11 was used as bait to screen a yeast one-hybrid library, successfully isolating and identifying a novel potential upstream regulator, LlbZIP11. Transient overexpression and virus-induced gene silencing (VIGS) assays revealed that the transcription factor LlbZIP11 functions as a negative regulator of bulbil formation in L. lancifolium. Further validation via luciferase (LUC) reporter gene assay and electrophoretic mobility shift assay (EMSA) demonstrated that LlbZIP11 specifically binds to the ACGTT cis-acting motif in the LlWOX11 promoter to repress its transcription. Currently, research on negative regulators of bulbil formation in L. lancifolium remains relatively scarce. This study is the first to demonstrate that transcription factor LlbZIP11 functions as a negative regulator, inhibiting bulbil formation of L. lancifolium by suppressing target gene LlWOX11's transcriptional activity. This work not only enriches the molecular regulatory theory of bulbil formation but also lays a solid foundation for systematically deciphering the regulatory mechanism underlying bulbil formation in lilies.

Keywords: Bulbil formation; Lilium lancifolium; LlWOX11; LlbZIP11; Transcriptional regulation.