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A role for a flavin‐containing mono‐oxygenase in resistance against microbial pathogens in Arabidopsis
Author(s) -
Koch Martina,
Vorwerk Sonja,
Masur Clarissa,
SharifiSirchi Gholamreza,
Olivieri Nicoletta,
Schlaich Nikolaus L.
Publication year - 2006
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2006.02813.x
Subject(s) - biology , mutant , virulence , pseudomonas syringae , arabidopsis , genetics , gene , microbiology and biotechnology , arabidopsis thaliana , transgene
Summary Using activation tagging in the Arabidopsis Col‐0 rps2‐101C background, we identified a mutant ( FMO1 ‐3D) that showed virtually no symptoms after inoculation with virulent Pseudomonas syringae pv. tomato DC3000 bacteria. The dominant, gain‐of‐function phenotype of the FMO1 ‐3D mutant is due to over‐expression of a class 3 flavin‐containing mono‐oxygenase (FMO). We recapitulated the FMO1 ‐3D mutant phenotype in independent transgenic Col‐0 lines over‐expressing the FMO1 cDNA under the control of the 35S CaMV promoter. The increased basal resistance observed in the FMO1 ‐3D mutant was also effective against the taxonomically unrelated downy mildew‐causing pathogen Hyaloperonospora parasitica . By investigating the progeny from crosses of the FMO1 ‐3D mutant with the NahG transgenic line, we showed that the enhanced basal resistance phenotype was dependent on the accumulation of salicylic acid. FMO1 ‐3D plants showed wild‐type resistant reactions after inoculation with avirulent bacteria, indicating that the R ‐gene‐mediated defence physiology was not compromised by FMO1 over‐expression. Transcripts of the class 3 FMO1 gene accumulated within 6 h after inoculation of wild‐type Col‐0 plants with avirulent Pst + avrRpt2 cells. Moreover, a T‐DNA insertion into the FMO1 gene resulted in enhanced susceptibility to virulent Pseudomonas and Hyaloperonospora parasitica , suggesting that expression of the FMO1 gene is a hitherto undescribed component of the plant's resistance repertoire. We discuss the possibility that the FMO may participate in the detoxification of virulence factors produced by pathogens.