Integrated Multi-Omics Analysis Uncovers Key Metabolic and Transcriptional Regulatory Networks in Blumea balsamifera Responding to Salt Stress

Changmao Guo^1*Zejun Mo¹Su Chen¹Mu Kai-lang¹Minghui Huang¹Yuan Yuan²Qiumei Luo¹Yongfang Wang¹Dandan Zhao¹Yuchen Liu^1*Yuxin Pang^1*

• ¹Guizhou University of Traditional Chinese Medicine, Guiyang, China
• ²Guangdong Pharmaceutical University School of Pharmacy, Guangzhou, China

Soil salinization is a key limiting factor for global agriculture and plant growth, while the salt tolerance response mechanism of the medicinal plant Blumea balsamifera (L.) DC. has not been systematically studied. In this study, 5-month-old seedlings of B. balsamifera were used as experimental materials, and five treatments were designed, including control (CK), low salt (LS), moderate salt (MS), high salt (HS) and extremely high salt (EHS), followed by the determination of growth, photosynthetic and physiological indices. Based on growth and physiological data, significant differences between the HS, EHS groups and the CK group appeared earlier, and key stress resistance indices peaked at 12 d of treatment, with plants presumed to enter the core stress response stage; therefore, the HS and EHS groups at this time point were selected for integrated multi-omics analysis. The results showed that with the intensification of salt stress, the net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of B. balsamifera all presented a downward trend; the activities of superoxide dismutase (SOD) and catalase (CAT) increased first and then decreased, which synergistically scavenged reactive oxygen species (ROS) with peroxidase (POD), and the changes in osmotic adjustment substances and the increase in lignin (LIG) content suggested that cell wall-related processes might be strengthened. Metabolomic analysis identified 677 and 692 Differentially Accumulated Metabolites (DAMs) in HS vs CK and EHS vs CK comparisons, respectively, with both groups enriched in the flavone and flavonol biosynthesis pathway; transcriptomic analysis identified 30,213 and 13,644 Differentially Expressed Genes (DEGs) in HS vs CK and EHS vs CK comparisons, respectively, with common enrichment in the oxidative phosphorylation pathway. Integrated analysis revealed that oxidative phosphorylation, flavone and flavonol biosynthesis, and cutin-suberine-wax biosynthesis were the core response pathways, which mediated the salt stress response by regulating DAMs such as fumaric acid, Kaempferol-3-O-Rutinoside, and Luteolin, as well as DEGs including flavonoid 3'-monooxygenase and peroxygenase-like isoform X2. This study clarifies the salt tolerance mechanism of B. balsamifera, providing theoretical support for its salt-tolerant breeding and the development of medicinal resources on salinized lands.