Understanding the effect of amino acids based biostimulant by an enantiomeric analysis of their active principles and a proteomic profiling approach

Plant biostimulants are products that contain multiple compounds and claim toactivate a wide range of plant responses. Amino acid based products are one exampleof biostimulants with a complex composition and different product characteristicsdepending on their sources and production processes. Amino acid biostimulants areobtained mainly by chemical or enzymatic protein hydrolysis and the type ofhydrolysis determine the content of free amino acids and their enantiomeric purity.While L-amino acids are biologically active, the application of D-amino acids has evenshown deleterious. With the aim to highlight different quality compositions of aminoacid biostimulants a comprehensive chiral analysis of different types of hydrolyzedprotein biostimulants was performed. Results confirmed the high purity in L-aminoacids in products obtained by enzymatic hydrolysis as well as a high racemization ratefor those obtained through a chemical hydrolysis. Furthermore the application of thecommercial biostimulant Terra-Sorb® Foliar with L-amino acids shows multipleagronomic effects such as the improvement of the photosynthetic process and theenhancement of crop tolerance to stress. A proteomic approach in wheat plants wasundertaken in order to understand which molecular mechanisms are involved in thestimulating effect of the product. The improvement of wheat productivity seems to bemediated by a combination of an enhanced CO2 fixation, a more active proteinmetabolism and a decrease of oxidative stress.