Protein Variants | Comment | Organism |
---|---|---|
additional information | the powdery mildew fungus Golovinomyces cichoracearum triggers defense responses in Arabidopsis mediated by the R gene RPW8.2. In a screen for mutants defective in RPW8.2-related resistance to powdery mildew, three plants with point mutations in xanthine dehydrogenase 1 (XDH1), including two that alter residues strictly conserved among xanthine dehydrogenases. The mutants show impaired resistance to powdery mildew and accumulate less H2O2 in the haustorial complex in epidermal cells invaded by the fungus. These point mutations decrease the activity of recombinant XDH1 proteins, in terms of both dehydrogenase activity and ROS production | Arabidopsis thaliana |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
chloroplast | - |
Arabidopsis thaliana | 9507 | - |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | Arabidopsis thaliana | autofluorescent objects (AFOs) formation within mesophyll cells of the mutant plants is a marker for xanthine accumulation with both spatial and temporal resolution, AFOs are highly enriched in xanthine | ? | - |
? | |
additional information | Arabidopsis thaliana Col-0 | autofluorescent objects (AFOs) formation within mesophyll cells of the mutant plants is a marker for xanthine accumulation with both spatial and temporal resolution, AFOs are highly enriched in xanthine | ? | - |
? | |
xanthine + NAD+ + H2O | Arabidopsis thaliana | - |
urate + NADH + H+ | - |
? | |
xanthine + NAD+ + H2O | Arabidopsis thaliana Col-0 | - |
urate + NADH + H+ | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | Q8GUQ8 | - |
- |
Arabidopsis thaliana Col-0 | Q8GUQ8 | - |
- |
Mammalia | - |
- |
- |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
epidermal cell | - |
Arabidopsis thaliana | - |
mesophyll cell | - |
Arabidopsis thaliana | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
hypoxanthine + NAD+ + 2 H2O | - |
Arabidopsis thaliana | urate + NADH + H+ | - |
? | |
hypoxanthine + NAD+ + 2 H2O | - |
Arabidopsis thaliana Col-0 | urate + NADH + H+ | - |
? | |
additional information | autofluorescent objects (AFOs) formation within mesophyll cells of the mutant plants is a marker for xanthine accumulation with both spatial and temporal resolution, AFOs are highly enriched in xanthine | Arabidopsis thaliana | ? | - |
? | |
additional information | autofluorescent objects (AFOs) formation within mesophyll cells of the mutant plants is a marker for xanthine accumulation with both spatial and temporal resolution, AFOs are highly enriched in xanthine | Arabidopsis thaliana Col-0 | ? | - |
? | |
xanthine + NAD+ + H2O | - |
Arabidopsis thaliana | urate + NADH + H+ | - |
? | |
xanthine + NAD+ + H2O | - |
Arabidopsis thaliana Col-0 | urate + NADH + H+ | - |
? |
Synonyms | Comment | Organism |
---|---|---|
XDH | - |
Mammalia |
XDH1 | - |
Arabidopsis thaliana |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
NAD+ | - |
Arabidopsis thaliana |
General Information | Comment | Organism |
---|---|---|
malfunction | the powdery mildew fungus Golovinomyces cichoracearum triggers defense responses in Arabidopsis mediated by the R gene RPW8.2. In a screen for mutants defective in RPW8.2-related resistance to powdery mildew, three plants with point mutations in xanthine dehydrogenase 1 (XDH1), including two that alter residues strictly conserved among xanthine dehydrogenases. The mutants show impaired resistance to powdery mildew and accumulate less H2O2 in the haustorial complex in epidermal cells invaded by the fungus. These point mutations decrease the activity of recombinant XDH1 proteins, in terms of both dehydrogenase activity and ROS production. Xanthine accumulation in the mutants is further induced by pathogen inoculation due to increased purine catabolism (mediated at least in part by XDH1) upon infection. Feeding uric acid suppressed the H2O2 accumulation normally observed in mesophyll cells of infected xdh1 mutant plants | Arabidopsis thaliana |
metabolism | dual and opposing roles of XDH1 in reactive oxygen species metabolism, detailed overview | Arabidopsis thaliana |
physiological function | dual and opposing roles of XDH1 in reactive oxygen species metabolism, detailed overview. The enzyme's basic function is in purine catabolism, catalyzing the conversion of hypoxanthine to xanthine and xanthine to uric acid. In mammals, xanthine dehydrogenases, which use NAD+ as electron acceptor to produce uric acid, can be posttranslationally modified to become xanthine oxidases, which use O2 as electron acceptor to produce reactive oxygen species (ROS). Because uric acid is a scavenger of ROS, the resulting influence of xanthine dehydrogenase on ROS status is likely responsible for its importance in a remarkably wide range of processes in mammals, including immunity | Mammalia |
physiological function | plant xanthine dehydrogenases do not undergo a posttranslational modification, las in mammals becoming xanthine oxidases, which use O2 as electron acceptor to produce reactive oxygen species. Plant enzymes appear capable of using both O2 and NAD+ as electron acceptors, as well as of producing high levels of ROS. In leaf mesophyll cells, XDH1 carries out xanthine dehydrogenase activity to produce uric acid in local and systemic tissues to scavenge H2O2 from stressed chloroplasts, thereby protecting plants from stress-induced oxidative damage. XDH1-derived uric acid is essential for removing H2O2 from stressed chloroplasts in leaf mesophyll cells. XDH1 plays spatially specified dual and opposing roles in modulation of ROS metabolism during defense responses in Arabidopsis thaliana as xanthine dehydrogenase and as xanthine oxidase, EC 1.17.3.2. XDH1 is required for scavenging age-dependent and pathogen-induced H2O2 in chloroplasts. XDH1 activity appears to be important for RPW8.2-mediated powdery mildew resistance. XDH1 appears to be an important tool allowing plants to harness and direct the power of ROS | Arabidopsis thaliana |