Extracellular elicitor protein that induces a strong defense response in strawberry and confers both local and systemic plant resistance against the fungal pathogen Colletotricum acutatum, the casual agent of anthracnose disease (PubMed:23530047). AsES activates a cascade of defense responses, including calcium influx, oxidative burst, hypersensitive cell-death response (HR), accumulation of autofluorescent compounds, cell-wall reinforcement with callose and lignin deposition, salicylic acid accumulation, and expression of defense-related genes, such as PR1, PG1, MYB30, RBOH-D, RBOH-F, CHI23, and FLS (PubMed:23530047, PubMed:26706064, PubMed:28635519). The oxidative burst consists in a progressive extracellular accumulation of H(2)O(2) that starts immediately after the contact with AsES and is preceded by a rapid and transient cell membrane depolarization. During this phase takes place also a rapid intracellular accumulation of NO at the chloroplasts. After the first extracellular H(2)O(2) production phase, two intracellular H(2)O(2) accumulation events occur, the first 2 hours after induction, and the second 7 hours after induction. AsES also produces a transient increase of ion leakage, and a progressive alkalinization of the extracellular medium (PubMed:26562675). Confers also local and systemic plant resistance against Botrytis cinerea in Arabidopsis thaliana. Systemic, but not local resistance is dependent on the length of exposure to AsES. The protection to B.cinerea is due to the induction of the plant defenses via the salicylic acid, jasmonic acid and ethylene signaling pathways (PubMed:26706064). Exhibits subtilisin-like proteolytic activity which is necessary but not sufficient for its elicitor function in strawberry plants. Probably induces defense by means of proteolysis of one or multiple host proteins that are specific targets of this protease (PubMed:23530047). The elicitor proteolytic activity is completely inhibited by PMSF. The activity is also significantly reduced by aprotinin (leading to 37% residual activity), by leupeptin (leading to 54% residual activity), by the ovomucoid trypsin inhibitor (leading to 65% residual activity), and by p-aminobenzamidine (leading to 26% residual activity). AsES can be combined well with commercial spray adjuvants, insecticides, herbicides and fungicides without losing any defense-inducing activity. The agricultural biostimulant PSP1, a formulation based on AsES is therefore a very promising candidate to efficiently control multiple fungal diseases under field conditions in monocot and dicot crops. Belongs to the peptidase S8 family.