Comparative Transcriptome and WGCNA Reveal Candidate Genes Involved in Petaloid Stamens in Paeonia Lactiflora

Abstract Background: The phenomenon of petaloid stamens in Paeonia lactiflora is an important cause of double flower formation. Although research on stamen development in model plants has progressed, the molecular mechanism of P. lactiflora petaloid stamens is still unclear. Results: In this study, a comparative transcriptomic analysis was performed on two cultivars of P. lactiflora (‘Fen Yu Nu’ and ‘Lian Tai’) with different stamen developmental patterns. Using transcriptome sequencing, 89,393 unigenes were identified in P. lactiflora. Trend analysis and weighted gene co-expression network analysis (WGCNA) indicated that 18 candidate genes were likely involved in petaloid stamens, including seven MADS-box genes PlAP3, PlDEFA, PlPI2, PlAG-1, PlSEP3, PlSEP1-1, and PlSEP1-2, and 11 transcription factors (TFs) PlTCP2, PlTCP4, PlTCP9, PlbHLH36, PlICE1, PlLBD38, PlNAC083, PlBLH11, PlPDF2, PlGBF1, and PlIIIA. Based on the selected candidate genes, a hypothetical model of gene expression network regulating petaloid stamens is proposed. Conclusions: Our results provide a collection of candidate genes for the analysis of P. lactiflora petaloid stamens, allowing for in-depth studies of the development pattern of P. lactiflora flower organs, and providing a theoretical basis for related research on petaloid stamens of other herbaceous flowers.