title: Pathogen-associated molecular pattern-triggered immunity and resistance to the root pathogen Phytophthora parasitica in Arabidopsis.
abstract: The cellulose binding elicitor lectin (CBEL) of the genus Phytophthora induces necrosis and immune responses in several plant species, including Arabidopsis thaliana. However, the role of CBEL-induced responses in the outcome of the interaction is still unclear. This study shows that some of CBEL-induced defence responses, but not necrosis, required the receptor-like kinase BAK1, a general regulator of basal immunity in Arabidopsis, and the production of a reactive oxygen burst mediated by respiratory burst oxidases homologues (RBOH). Screening of a core collection of 48 Arabidopsis ecotypes using CBEL uncovered a large variability in CBEL-induced necrotic responses. Analysis of non-responsive CBEL lines Ws-4, Oy-0, and Bla-1 revealed that Ws-4 and Oy-0 were also impaired in the production of the oxidative burst and expression of defence genes, whereas Bla-1 was partially affected in these responses. Infection tests using two Phytophthora parasitica strains, Pp310 and Ppn0, virulent and avirulent, respectively, on the Col-0 line showed that BAK1 and RBOH mutants were susceptible to Ppn0, suggesting that some immune responses controlled by these genes, but not CBEL-induced cell death, are required for Phytophthora parasitica resistance. However, Ws-4, Oy-0, and Bla-1 lines were not affected in Ppn0 resistance, showing that natural variability in CBEL responsiveness is not correlated to Phytophthora susceptibility. Overall, the results uncover a BAK1- and RBOH-dependent CBEL-triggered immunity essential for Phytophthora resistance and suggest that natural quantitative variation of basal immunity triggered by conserved general elicitors such as CBEL does not correlate to Phytophthora susceptibility.
authors.affiliation: Université de Toulouse, UPS, Laboratoire de Recherche en Sciences Végétales, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Larroque
authors.forename: Elodie
authors.initials: E
authors.lastname: Belmas
authors.forename: Thomas
authors.initials: T
authors.lastname: Martinez
authors.forename: Sophie
authors.initials: S
authors.lastname: Vergnes
authors.forename: Nathalie
authors.initials: N
authors.lastname: Ladouce
authors.forename: Claude
authors.initials: C
authors.lastname: Lafitte
authors.forename: Elodie
authors.initials: E
authors.lastname: Gaulin
authors.forename: Bernard
authors.initials: B
authors.lastname: Dumas
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D037102:Lectins / Q000378:metabolism*; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D010838:Phytophthora / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D005656:Fungal Proteins; D037102:Lectins; D019255:NADPH Oxidases; C022709:superoxide-forming enzyme; C463660:BAK1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: Arabidopsis; Phytophthora.; cell death; elicitor; immunity; natural variability; necrosis; oomycete