Comparative Physiological and Transcriptome Analysis of Crossostephium chinense Reveals Its Molecular Mechanisms of Salt Tolerance

is a wild species with strong salt tolerance that has great potential to improve the salt tolerance of cultivated chrysanthemums. Conversely, the unique salt-tolerant molecular mechanisms of are still unclear. This study performed a comparative physiological and transcriptome analysis of , , and three hybrids to investigate the salt-tolerant molecular mechanisms of . The physiological results showed that maintained higher superoxide dismutase (SOD) activity, alleviating oxidative damage to the membrane. KEGG enrichment analysis showed that plant hormone signaling transduction and the MAPK signaling pathway were mostly enriched in and hybrids under salt stress. Further weighted gene co-expression network analysis (WGCNA) of DEGs suggested that abscisic acid (ABA) signaling transduction may play a significant role in the salt-tolerant mechanisms of and hybrids. The tissue-specific expression patterns of the candidate genes related to ABA signaling transduction and the MAPK signaling pathway indicate that genes related to ABA signaling transduction demonstrated significant expression levels under salt stress. This study offers important insights into exploring the underlying salt-tolerant mechanisms of mediated by ABA signaling transduction and broadens our understanding of the breeding strategies for developing salt-tolerant cultivars utilizing salt-tolerant chrysanthemum germplasms.