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; MARTINEZ ZAMORA, MARTIN G.; ZIPFEL, CYRIL; ASURMENDI, SEBASTIÁN; DIAZ RICCI, JUAN CARLOS

MOLECULAR PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019

1464-6722

Acremonium strictum elicitor subtilisin (AsES) is a 34-kDa serineprotease secreted by the strawberry fungal pathogen Acremoniumstrictum. On AsES perception, a set of defence reactions are induced, both locally and systemically, in a wide variety of plant species and against pathogens of alternative lifestyles. However, it isnot clear whether AsES proteolytic activity is required for triggering a defence response or if the protein acts itself as an elicitor. Toinvestigate the necessity of the protease activity to activate the defence response, AsES coding sequences of the wild-type gene anda mutant on the active site (S226A) were cloned and expressedin E. coli. Our data show that pre-treatment of Arabidopsis plantswith inactive proteins, i.e. inhibited with phenylmethylsulphonylfluoride and mutant, resulted in an increased systemic resistanceto Botrytis cinerea and expression of defence-related genes in atemporal manner that mimics the effect already reported for thenative AsES protein. The data presented in this study indicate thatthe defence eliciting property exhibited by AsES is not associatedwith its proteolytic activity. Moreover, the enhanced expression ofsome immune marker genes, seedling growth inhibition and theinvolvement of the co-receptor BAK1 observed in plants treatedwith AsES suggests that AsES is being recognized as a pathogenassociated molecular pattern by a leucine-rich repeat receptor.The understanding of the mechanism of action of AsES will contribute to the development of new breeding strategies to conferdurable resistance in plants.