Full-length transcriptome sequencing analysis and characterization of MADS-box genes in Rhododendron fortunei

Rhododendron fortunei, an endemic Chinese species, holds significant ornamental and economic value. MADS-box transcription factors play pivotal roles in regulating diverse aspects of plant growth and development. However, molecular biological research on R. fortunei remains limited, particularly concerning its MADS-box gene family. In this study, we present the first full-length transcriptome analysis of R. fortunei using SMRT sequencing technology, enabling identification and comprehensive characterization of its MADS-box genes. We obtained 40,782 high-quality unigenes, with an average length of 2,366 bp. In total, 39,214 (96.16%) unigenes were functionally annotated against seven public databases. Core biological functions of the unigenes were characterized through GO, KOG, and KEGG pathway analyses. A total of 956 LncRNAs and 2,051 TFs were further identified. Using the unigenes as reference, RNA-seq analysis delineated global gene expression patterns. Furthermore, we identified 36 MADS-box genes and characterized their physicochemical properties, phylogenetic relationships, and conserved motifs. Notably, 34 MIKC-type RfMADS genes exhibited tissue-specific expression across vegetative and floral organs, suggesting their functional relevance in R. fortunei floral development. These findings advance our understanding of the genetic information of R. fortunei and establish a foundation for genetic studies. Moreover, this study paves the way for comprehensive exploration of molecular mechanisms underlying the MADS-box genes in floral development of R. fortunei.