Genome-Wide Analysis of the LdERF Gene Subfamily and Functional Characterization of LdERF179 During Bulblet Regeneration in Lilium

The AP2/ERF transcription factor family plays crucial roles in plant growth, development, and stress responses, as well as in organ regeneration. Here, a comprehensive genome-wide analysis of ERF subfamily of Lilium davidii var. unicolor (Lanzhou lily) was performed, and the functional role of a candidate gene, LdERF179, in bulblet regeneration was further investigated. A total of 206 LdERF genes were identified and phylogenetic evolution, chromosomal distribution, gene structure, conserved motifs, cis-regulatory elements, and collinearity were analyzed. Expression patterns suggested that there are 6 expression patterns of LdERF genes exhibited tissue-specific and stage-specific expression profiling during bulblet regeneration. LdERF179 was highly expressed at the regeneration initiation (RI) stage (S1), suggested its potential involvement in the early morphogenesis of bulb regeneration. Subcellular localization analysis demonstrated that LdERF179 protein localized in the nucleus. The results of the virus-induced gene silencing (VIGS) functional validation analysis show that suppression of LdERF179 significantly reduced bulblet formation efficiency from 40.67% to 9.43%. Further expression analysis indicated some key genes involved in auxin biosynthesis, transport, and signaling, and some regeneration-related genes showed decreased expression, such as TRV2-LdERF179, while increased expression was found in LdERF179-OE (LdASA1, LdAUX1, LdWOX11). Therefore, we propose that LdERF179 influenced the morphogenesis of bulblet regeneration by regulating the expression of auxin metabolism-related genes and key regeneration genes. However, further functional validation was required to clarify how LdERF179 regulates auxin metabolism genes and key regeneration genes. This study provides new insights into the molecular regulatory network of lily bulblet regeneration and offers potential candidate genes for improving vegetative propagation efficiency in lilies.