Genome Assembly Provides New Insights Into the Development of Flower Organs in <i>Lonicera macranthoides</i>

Lonicera macranthoides is an important medicinal plant in the genus Lonicera, and its flowers possess significant medicinal value. 'Jincuilei' (JCL), a newly bred variety, is characterized by a long flowering period and persistently closed corollas. To investigate the molecular mechanism underlying the non-dehiscent corolla phenotype in JCL, we performed whole-genome sequencing, transcriptomics, and metabolomics analyses of this variety. The results showed that the L. macranthoides genome size is approximately 879.83 Mb, assembled into 439 contigs with a contig N50 of 67.38 Mb, which were further scaffolded into 9 pseudochromosomes. Comparative genomics analysis revealed that the divergence time between Lonicera japonica (Japanese honeysuckle) and L. macranthoides occurred approximately 15.1 million years ago (Mya). Within L. macranthoides, comparisons identified 525 expanded and 555 contracted gene families relative to L. japonica. Analysis of endogenous hormone levels in floral organs of JCL and wild-type (WT) plants across different developmental stages revealed highly significant differences in jasmonic acid (JA) content at all stages. Further transcriptomic and metabolomic analyses indicated that both the JA biosynthesis and signaling pathways play key roles in regulating corolla dehiscence. These findings provide valuable insights into Caprifoliaceae evolution and the molecular basis of corolla morphogenesis in L. macranthoides.