Comparative transcriptomics identifies LlCSLE1 as a key regulator of cellulose accumulation during bulbil formation in lily

In lilies, bulbils are a specialized form of axillary bud essential for vegetative reproduction. To elucidate the molecular mechanisms regulating their formation, we performed transcriptome sequencing on leaf axil tissues from four lily varieties with contrasting bulbil-forming and non-bulbil-forming phenotypes. Analysis revealed differentially expressed genes (DEGs) notably enriched in carbohydrate metabolism pathways. During bulbil development, a gradual increase in leaf axil cellulose content was observed as measured by the anthrone colorimetric method. This correlated with the upregulation of the key cellulose synthase-like gene LlCSLE1 as determined by real-time quantitative PCR. Functional validation confirmed that virus-induced gene silencing (VIGS) of LlCSLE1 led to a significant reduction in both cellulose content and bulbil number. Our findings establish LlCSLE1 as an important regulator of bulbil formation, underscoring the critical role of cellulose-mediated cell wall remodeling in this process. This study provides a molecular foundation for understanding vegetative reproduction and advances molecular breeding strategies in lilies.