Proteomic analysis reveals lignin and trehalose pathways involved in cold stress response of elephant grass

Elephant grass (Cenchrus purpureus) is a high-yield perennial warm-season energy plant and forage grass. However, when cultivated in cold regions, elephant grass shows poor cold tolerance and low winter survival rates, with its root system playing a crucial role in overwintering, though the molecular mechanisms underlying this cold tolerance are still unclear. In this study, we investigated the molecular mechanisms of elephant grass under low-temperature stress using Tandem Mass Tags (TMT) technology to characterize proteome changes. We found that cold stress led to the differential expression of 341 proteins in 'Chuanyu No.1' elephant grass. In the roots of elephant grass, cold stress increased the expression of peroxidases involved in lignin biosynthesis, sucrose synthase and raffinose synthase involved in raffinose synthesis, as well as trehalose-6-phosphate phosphatase involved in trehalose biosynthesis. This favored the accumulation of lignin, raffinose and trehalose, enhancing cold tolerance. Moreover, exogenous application of trehalose enhanced cold tolerance in elephant grass by increasing the activities of CAT and POD. Additionally, 'Chuanyu No.1' resisted cold stress by increasing glyceraldehyde-3-phosphate dehydrogenase in glycolysis and F-ATP protein in oxidative phosphorylation, enhancing energy synthesis. This study provides a theoretical basis for understanding root response to cold stress and points out that further research on forage grass tolerance mechanisms is needed.