The Transcription Factor LoTDF1 Plays a Role in Early Anther Development in Lily (Lilium Oriental Hybrids)

Lilies are one of the most popular ornamental flowers in the world. However, the abundant pollen produced in their anthers causes significant inconvenience for producers and consumers. Pollen abortion induced by molecular breeding techniques is one of the effective ways to solve this problem. In this study, the LoTDF1 gene, which is involved in regulating lily anther development, was identified and cloned from lily anthers based on transcriptome data. The open reading frame of LoTDF1 is 936 bp and encodes a protein with 311 amino acids. Multiple sequence alignment and phylogenetic tree analysis revealed that the LoTDF1 protein contained a conserved R2R3 domain, belonging to the MYB transcription factor family. Subcellular localization and transcriptional activation assays demonstrated that LoTDF1 localized to the nucleus and functioned as a transcription activator. The transcriptional activation domain was located within the last 195 amino acids (117–311a) of the C-terminus, and there may be more than one transcriptional activation domain in the region. The expression level of the LoTDF1 gene was highest during the pollen mother cell (PMC) stage of lily anther development (2 cm anther), followed by the tetrad stage (4 cm anther). In situ hybridization experiments further confirmed that LoTDF1 transcripts were predominantly localized in PMCs, tapetal cells, middle layer cells, dyads, and tetrads. The experiment data suggest that LoTDF1 plays a critical role in regulating early anther development in lily. LoTDF1 could be a promising candidate gene for molecular breeding strategies aimed at developing pollen-free lily cultivars to enhance commercial and consumer appeal.