Genome-Wide Analysis of the MADS-Box Gene Family and Expression Pattern Under Abiotic Stresses in Lilium davidii var. unicolor

The MADS-box gene family encodes a critical class of transcription factors that regulate diverse developmental processes in plants. However, its role in abiotic stress responses remains poorly characterized in <i>Lilium davidii</i> var. <i>unicolor</i> (Lanzhou lily). In this study, we identified 62 <i>LdMADS</i> genes in the Lanzhou lily genome, classifying them into 17 Type I and 45 Type II members. Notably, the SOC1 subfamily exhibited a pronounced expansion. These <i>LdMADS</i> members were distributed across all twelve chromosomes and displayed considerable structural variation, with some genes harboring exceptionally long introns. Tissue-specific expression profiling revealed that M-type and MIKC* genes were predominantly and specifically expressed in ovaries and anthers, whereas MIKC^C members exhibited complex and diverse expression patterns across multiple tissues. The selection of candidate <i>LdMADS</i> genes for abiotic stress response was based on their transcript abundance in leaf and root tissues, together with the enrichment of their <i>cis</i>-acting elements. The expression of these <i>LdMADS</i> genes under drought, heat, and cold stresses was further examined by qRT-PCR. Among them, <i>LdMADS4</i> and <i>LdMADS14</i> from the SEP subfamily, as well as <i>LdMADS25</i> and <i>LdMADS26</i> from the SOC1 subfamily, responded to multiple stress conditions. This study provides functional clues for the roles of MADS-box genes in the development and stress responses of Lanzhou Lily.