Response of dauciform roots to low phosphorus stress: Insights based on ecophysiology, transcriptomics, and metabolomics analysis

Low available phosphorus presents significant challenges to ecological health and agricultural development. The dauciform roots of Cyperaceae, unique root structures formed in response to low-phosphorus environments, exhibit robust phosphorus acquisition capabilities. However, the underlying molecular mechanisms remain unexplored. This study investigated the dauciform roots at different developmental stages under varying phosphorus levels using a comprehensive approach combining ecophysiology, transcriptomics, and metabolomics for the first time. The results revealed no significant difference in biomass between low- and high-phosphorus conditions (P > 0.05). However, the low phosphorus group exhibited significantly higher phosphorus absorption indicators, including root-shoot ratio, root length, root tip number, organic acid secretion rate, and acid phosphatase activity (P < 0.05). Key upregulated pathways included glycolysis/gluconeogenesis, the TCA cycle, plant hormone signal transduction, and lipid metabolism. The MYB, WRKY and bHLH transcription factor families were identified as likely primary regulators involved. The metabolic profile revealed enrichment in pathways related to amino acid and carbohydrate synthesis. These findings suggested that in response to low phosphorus, the dauciform roots maintain energy supply and enhanced root exudates to convert insoluble phosphorus, driven by carbon and lipid metabolism. Furthermore, it regulates root morphological changes through carbohydrates, hormones, and transcription factors. This study provides insights into the molecular mechanisms underlying the formation and response of dauciform roots, offering a theoretical foundation for the genetic breeding and application of low-phosphorus-tolerant crops.