A fungal protease named AsES triggers antiviral immune responses and effectively restricts virus infection in arabidopsis and Nicotiana benthamiana plants

CARO, MARIA DEL PILAR; VENTURUZZI, ANDREA LAURA; MOSCHEN, SEBASTIAN; SALAZAR, SERGIO MIGUEL; DÍAZ-RICCI, JUAN CARLOS; ASURMENDI, SEBASTIAN

ANNALS OF BOTANY

OXFORD UNIV PRESS

Año: 2022

0305-7364

? Background and Aims Plants have evolved complex mechanisms to fight against pathogens. Among thesemechanisms, pattern-triggered immunity (PTI) relies on the recognition of conserved microbe- or pathogenassociatedmolecular patterns (MAMPs or PAMPs, respectively) by membrane-bound receptors. Indeed, PTI restrictsvirus infection in plants and, in addition, BRI1-associated kinase 1 (BAK1), a central regulator of PTI, playsa role in antiviral resistance. However, the compounds that trigger antiviral defences, along with their molecularmechanisms of action, remain mostly elusive. Herein, we explore the role of a fungal extracellular subtilase namedAsES in its capacity to trigger antiviral responses.? Methods In this study, we obtained AsES by recombinant expression, and evaluated and characterized its capacityto trigger antiviral responses against Tobacco mosaic virus (TMV) by performing time course experiments,analysing gene expression, virus movement and callose deposition.? Key Results The results of this study provide direct evidence that exogenous treatment with recombinant AsESincreases a state of resistance against TMV infection, in both arabidopsis and Nicotiana benthamiana plants. Also,the antiviral PTI response exhibited by AsES in arabidopsis is mediated by the BAK1/SERK3 and BKK1/SERK4co-receptors. Moreover, AsES requires a fully active salicylic acid (SA) signalling pathway to restrict the TMVmovement by inducing callose deposition. Additionally, treatment with PSP1, a biostimulant based on AsES as theactive compound, showed an increased resistance against TMV in N. benthamiana and tobacco plants.? Conclusions AsES is a fungal serine protease which triggers antiviral responses relying on a conserved mechanismby means of the SA signalling pathway and could be exploited as an effective and sustainable biotechnologystrategy for viral disease management in plants.