title: Glucosinolate-derived isothiocyanates impact mitochondrial function in fungal cells and elicit an oxidative stress response necessary for growth recovery.
abstract: Glucosinolates are brassicaceous secondary metabolites that have long been considered as chemical shields against pathogen invasion. Isothiocyanates (ITCs), are glucosinolate-breakdown products that have negative effects on the growth of various fungal species. We explored the mechanism by which ITCs could cause fungal cell death using Alternaria brassicicola, a specialist Brassica pathogens, as model organism. Exposure of the fungus to ICTs led to a decreased oxygen consumption rate, intracellular accumulation of reactive oxygen species (ROS) and mitochondrial-membrane depolarization. We also found that two major regulators of the response to oxidative stress, i.e., the MAP kinase AbHog1 and the transcription factor AbAP1, were activated in the presence of ICTs. Once activated by ICT-derived ROS, AbAP1 was found to promote the expression of different oxidative-response genes. This response might play a significant role in the protection of the fungus against ICTs as mutants deficient in AbHog1 or AbAP1 were found to be hypersensitive to these metabolites. Moreover, the loss of these genes was accompanied by a significant decrease in aggressiveness on Brassica. We suggest that the robust protection response against ICT-derived oxidative stress might be a key adaptation mechanism for successful infection of host plants by Brassicaceae-specialist necrotrophs like A. brassicicola.
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Calmes
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: N'Guyen
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Jérome
authors.initials: J
authors.lastname: Dumur
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Brisach
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Campion
authors.affiliation: Universitatea de Ştiinţe Agronomice şi Medicinǎ Veterinarǎ Bucureşti Bucharest, Romania.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Iacomi
authors.affiliation: Universitatea de Ştiinţe Agronomice şi Medicinǎ Veterinarǎ Bucureşti Bucharest, Romania.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Pigné
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Eva
authors.initials: E
authors.lastname: Dias
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: David
authors.initials: D
authors.lastname: Macherel
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Guillemette
authors.affiliation: Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 IRHS, SFR 4207 QUASAV Angers, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Simoneau
keywords: Alternaria brassicicola; ROS; isothiocyanates; mitochondria; oxidative stress