Unveiling the adaptive strategies in Blumea Balsamifera roots under salt stress through integrated physiological and multi-omics analysis.

Abstract

Background: Soil salinization is a growing constraint on agricultural productivity, yet the adaptive mechanisms of many medicinal plants-particularly Blumea balsamifera, a species of significant economic and pharmacological value-remain poorly understood. In this study, five treatments-CK (control), LS (low salt), MS (medium salt), HS (high salt), and EHS (extremely high salt)-were established to systematically investigate the comprehensive effects of salt stress on the growth, physiological metabolism, and molecular regulatory networks of B. balsamifera.

Results: The results showed that salt stress significantly inhibited the growth of B. balsamifera, causing leaf chlorosis and wilting. In roots, the activities of antioxidant enzymes (SOD, POD, CAT) and the level of malondialdehyde (MDA) initially increased and then decreased, while the accumulation of osmoregulatory substances (PRO, SS, SP) and lignin (LIG) progressively increased. Transcriptomic analysis identified 5,701 differentially expressed genes (DEGs) shared between the HS vs CK and EHS vs CK comparisons, which were significantly enriched in functional terms including transcription factor activity, cell wall organization, plant hormone signal transduction. Metabolomic analysis identified 590 and 647 differentially accumulated metabolites (DAMs) in the HS vs CK and EHS vs CK comparisons, respectively. Under moderate stress, flavonoid synthesis and cutin/suberin biosynthesis pathways were significantly enriched, whereas under extreme stress, the phenylpropanoid pathway, carbohydrate metabolism pathway, and oxylipin/jasmonate-related metabolism pathways were significantly activated. Integrated multi-omics analysis further revealed that cutin, suberin, and wax biosynthesis, phenylpropanoid biosynthesis, and oxylipin/jasmonate-related metabolism are the core synergistic pathways in the root response of B. balsamifera to salt stress, mediating physical barrier construction, chemical defense and structural reinforcement, and lipid signal transduction, respectively.

Conclusion: Collectively, these findings uncover a multilayered adaptive strategy in B. balsamifera roots under salt stress, namely physical barrier formation, chemical-structural defense, and membrane lipid signaling. These results provide theoretical insights and key molecular targets for breeding salt-tolerant varieties and developing stress-resilient cultivation strategies.