Chicken feather protein hydrolysate as a biostimulant improves the growth of wheat seedlings by affecting biochemical and physiological parameters

We derived a protein hydrolysate with rich content, which includes proteinogenic and nonproteinogenic amino acids, from chicken feathers by using an alkaline hydrolysis procedure with high yield success. After foliar application of aqueous solutions (0.05%, 0.075%, and 0.1%) of chicken feather protein hydrolysate (CFPH) to the seedlings of wheat (Triticum aestivum L. 'Altindane' and 'Bezostaya'), their effects were evaluated on important physiological and biochemical parameters. Treating plants with CFPH stimulated the expression of RuBisCo and increased root and shoot lengths, fresh and dry weights of the seedlings, and photosynthetic pigment content. In addition, applying CFPH at 0.075% and 0.1% concentrations decreased the content of reactive oxygen species, such as O-2(-) and H2O2, and the levels of lipid peroxidation (as malondialdehyde) and phenolic compounds, while augmenting free proline content. On the contrary, CFPH application ameliorated the antioxidant parameters, including enzymatic and nonenzymatic antioxidants. CFPH stimulated the activities of guaiacol, ascorbate, and glutathione peroxidase while it did not affect those of superoxide dismutase and catalase. Enzyme activity results agreed well with the isoenzyme expression profiles. In conclusion, the application of CFPH improved the parameters under consideration in wheat seedlings, suggesting that CFPH has the potential to be used as a suitable biostimulant in plant cultivation.