Unraveling the impact of protein hydrolysates on rhizosphere microbial communities: Source matters

Protein hydrolysates (PHs), derived from enzymatic or chemical protein hydrolysis, are recognized as effective biostimulants for sustainable and environmentally safe crop production. Extensive research has highlighted their benefits and demonstrated their capacity to enhance crop growth and yield under various abiotic stresses, making them increasingly popular in agriculture. To fully unlock the potential of PHs, more research is needed to elucidate their mechanisms of action. This involves understanding plant preferences for different PH sources as well as their impact on rhizosphere microbial communities. This study explored how PHs from plant and animal sources affect plant growth and rhizosphere microbiota across five different plant species. We found variations in plant responses to different PHs, indicating differing plant preferences for nitrogen sources and protein uptake mechanisms among species. There was an increase in beneficial microbial taxa in response to PH application, including Pseudomonas, Paraburkholderia, and Mortierella. Functional analysis also indicated variations in chemoheterotrophy, nitrate respiration and reduction, based on crop species. In conclusion, this research shows the potential of PHs as biostimulants for diverse crops. Their effectiveness is dependent on various factors, including source, production process and plant species, having a positive impact on both plant growth and rhizosphere microbial communities.