Priming with Porcine Blood Polypeptide Enhances Salt Tolerance in Wheat Seedlings

Porcine blood polypeptide (PBP) has been reported to play roles in plant growth. However, its functions in alleviating salt stress in wheat remain unclear. The present study was conducted to investigate the physiological and biochemical mechanisms underlying the effects of PBP on wheat salt tolerance. Morphological analysis showed that PBP-primed seedlings exhibited improved growth performance, significantly greater biomass accumulation, and enhanced root system development. Physiological assessments showed that primed seedlings displayed higher values of <i>Pn</i>, <i>Gs</i>, <i>Tr</i>, <i>Fv</i>/<i>Fm</i>, <i>Fv</i>'/<i>Fm</i>', <i>Φ</i>_PSII, and NPQ, along with increased contents of total chlorophyll, Pro, TSS, and RWC. In addition, the activities of antioxidant enzymes, including SOD, CAT, POD, and APX, were significantly elevated, whereas the levels of H₂O₂, O₂^-, MDA, and REC were significantly reduced. PCA indicated that antioxidant enzyme activity, osmotic regulation, and ROS accumulation were the major factors associated with the PBP-mediated salt stress response. Furthermore, qRT-PCR analysis suggested that exogenous PBP might enhance wheat salt tolerance by coordinately modulating multiple molecular mechanisms. Taken together, this study broadens the potential applications of PBP by demonstrating its capacity to improve wheat salt tolerance.