Heterologous expression of AsES, an elicitor subtilisin isolated from Acremonium strictum.

CARO MA. DEL PILAR; MARTÍNEZ ZAMORA, MARTÍN G.; DÍAZ RICCI, JUAN C.

Rosario, Santa Fe.

Congreso; SAIB 51º Annual Meeting; 2014

AsES protein, a subtilisin like serine protease isolated from the avirulent fungus Acremonium strictum, induces plant defence response in strawberry and other species. Sequence analysis reveals that AsES possesses a typical pre-pro-mature organization that consists of a signal sequence, an inhibitor domain (pro-peptide) in the N-terminal region with chaperone function and a mature proteinase domain with catalytic activity. The aim of this work was to obtain AsES protein by heterologous expression in order to assess its elicitor activity. The coding sequence of AsES pro-protein was cloned and expressed in Escherichia coli and then purified by affinity chromatography. Proteolytic activity was evaluated in vitro by specific substrate hydrolysis and elicitor activity was assessed through ROS formation and protection against Colletotrichum acutatum, the causal agent of anthracnose disease. The results of this study suggest that AsES mature protein of 34 kDa is formed by autolysis of the pro-peptide (45 kDa) after its expression and it is functionally active. The mature protein can protect plants against anthracnose and produces the accumulation of ROS at 4 hpi. Direct application of AsES recombinant protein could be used as a new strategy for diseases biocontrol helping to reduce agrochemicals minimizing environmental impact.