Study on the physiological mechanism and molecular regulatory network of Blumea balsamifera in response to drought stress.

Drought restricts plant growth and agricultural production. As an important medicinal plant, Blumea balsamifera is sensitive to water, but there is still a lack of systematic research on its drought response mechanism. In this study, four-month-old B. balsamifera seedlings were used as materials, and three groups were set up: normal irrigation (CK), drought stress (DS), and rewatering recovery (RW). The results showed that drought significantly inhibited the growth and photosynthesis of B. balsamifera. With the prolongation of stress time (day 12), the limiting factor of photosynthesis changed from initial stomatal limitation to non - stomatal limitation. In terms of physiology and biochemistry, B. balsamifera increased MDA content by actively reducing SPAD value and relative water content of leaves; and activates the antioxidant enzyme system to remove ROS, synergistically accumulates lignin, soluble sugar, proline and other osmotic adjustment substances, and jointly maintains cell water balance and membrane system stability. Through transcriptome and proteome analysis, 20,874 DEGs and 2770 DEPs were screened out, which were significantly enriched in terms related to ribosome, oxidoreductase activity, biosynthesis of unsaturated fatty acids and other pathways. A total of 55 drought - related DEGs - DEPs were identified by two - omics, and 18 key regulatory genes were screened. In summary, B. balsamifera formed a comprehensive drought resistance mechanism through photosynthesis, physiology and DEGs - DEPs network. This study provides theoretical support for the breeding and resource development of B. balsamifera, and also provides reference for the study of stress resistance of other medicinal plants.