The fungal subtilase AsES elicits a PTI‐like defence response in Arabidopsis thaliana plants independently of its enzymatic activity

CARO, MARÍA DEL PILAR; HOLTON, NICHOLAS; CONTI, GABRIELA; VENTURUZZI, ANDREA LAURA; MARTÍNEZ ZAMORA, MARTIN GUSTAVO; ZIPFEL, CYRIL; ASURMENDI, SEBASTIAN; DÍAZ RICCI, JUAN CARLOS

MOLECULAR PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 vol. 21 p. 147 - 159

1464-6722

Acremonium strictum elicitor subtilisin (AsES) is a 34-kDa serineproteasesecreted by the strawberry fungal pathogen A. strictum.On AsES perception, a set of defence reactions is induced, bothlocally and systemically, in a wide variety of plant species andagainst pathogens of alternative lifestyles. However, it is not clearwhether AsES proteolytic activity is required for triggering a defenceresponse or if the protein itself acts as an elicitor. To investigatethe necessity of the protease activity to activate the defenceresponse, AsES coding sequences of the wild-type gene and amutant on the active site (S226A) were cloned and expressed inEscherichia coli. Our data show that pretreatment of Arabidopsisplants with inactive proteins, i.e. inhibited with phenylmethylsulphonylfluoride (PMSF) and mutant, resulted in an increasedsystemic resistance to Botrytis cinerea and expression of defencerelatedgenes in a temporal manner that mimics the effectalready reported for the native AsES protein. The data presentedin this study indicate that the defence-eliciting property exhibitedby AsES is not associated with its proteolytic activity. Moreover,the enhanced expression of some immune marker genes, seedlinggrowth inhibition and the involvement of the co-receptor BAK1observed in plants treated with AsES suggests that AsES is beingrecognized as a pathogen-associated molecular pattern by aleucine-rich repeat receptor. The understanding of the mechanismof action of AsES will contribute to the development of newbreeding strategies to confer durable resistance in plants.