Exogenous porcine blood polypeptide alleviates drought damage in wheat

Previous studies have demonstrated that porcine blood polypeptide (PBP) could mitigate plant damage under adverse conditions. This study was conducted to systematically investigate the possible role of PBP in enhancing drought resistance in wheat through comprehensive physiological and biochemical analyses, as well as transcriptomic analysis. Morphological observations revealed that PBP-primed seedlings exhibited improved growth, biomass accumulation and root system under drought stress. Physiological and biochemical analyses demonstrated that primed seedlings existed significantly higher values in P_n, G_s, T_r, F_v/F_m, F_v'/F_m', Φ_PSII and NPQ. Additionally, increased contents of total chlorophyll, Pro, TSS, and RWC were observed, along with enhanced activities of antioxidant enzymes, such as SOD, CAT, APX, and POD. In contrast, concentrations of H₂O₂, O₂^-, MDA, and REC were significantly reduced. Principal component analysis (PCA) indicated that PBP alleviated drought-induced damage primarily through enhancing antioxidant capacity and osmotic adjustment. Transcriptome analysis showed that PBP triggered an active adaptation mechanism against drought, as evidenced by the significant enrichment of DEGs involved in "ion transport", "glyoxysome", and "MAPK signaling pathway". Correlation analysis revealed that expression levels of genes enriched in aforementioned terms were, on the whole, significantly positively correlated with both enzyme activities and levels of osmotic regulatory substances. Overall, this study unveils a novel application for PBP, establishes a theoretical basis for its use in improving drought resistance in wheat, and provides an innovative strategy for boosting wheat production in arid and semi-arid regions.