Aldehyde oxidase with a broad substrate specificity (PubMed:28188272). Involved in the accumulation of benzoic acid (BA) in siliques (PubMed:19297586). Delays and protects siliques from senescence by catalyzing aldehyde detoxification in siliques. Catalyzes the oxidation of an array of aromatic and aliphatic aldehydes, including vanillin and the reactive carbonyl species (RCS) acrolein, 4-hydroxyl-2-nonenal (HNE), and malondialdehyde (MDA) (PubMed:28188272). H2O + indole-3-acetaldehyde + O2 = (indol-3-yl)acetate + H(+) + H2O2 an aldehyde + H2O + O2 = a carboxylate + H(+) + H2O2 benzaldehyde + H2O + O2 = benzoate + H(+) + H2O2 H2O + hexanal + O2 = H(+) + H2O2 + hexanoate 1-naphthaldehyde + H2O + O2 = 1-naphthoate + H(+) + H2O2 H2O + O2 + vanillin = H(+) + H2O2 + vanillate H2O + malonaldehyde + O2 = 3-oxopropanoate + H(+) + H2O2 citral + H2O + O2 = 3,7-dimethylocta-2,6-dienoate + H(+) + H2O2 acrolein + H2O + O2 = acrylate + H(+) + H2O2 (E)-4-hydroxynon-2-enal + H2O + O2 = (E)-4-hydroxynon-2-enoate + H(+) + H2O2 (E)-cinnamaldehyde + H2O + O2 = (E)-cinnamate + H(+) + H2O2 H2O + indole-3-carbaldehyde + O2 = H(+) + H2O2 + indole-3-carboxylate H2O + O2 + propanal = H(+) + H2O2 + propanoate dodecanal + H2O + O2 = dodecanoate + H(+) + H2O2 H2O + O2 + salicylaldehyde = H(+) + H2O2 + salicylate Binds 2 [2Fe-2S] clusters. Binds 1 Mo-molybdopterin (Mo-MPT) cofactor per subunit. Inhibited by Cu(2+). kcat is 95.2 sec(-1) with benzoic acid (BA) as substrate, 1.904 sec(-1) with indole-3-acetaldehyde as substrate, and 436.5 sec(-1) with cinnamylaldehyde as substrate (at pH 7, PubMed:19297586). Optimum pH is 7. Optimum temperature is 30 degrees Celsius. Aldehyde oxidases (AO) are homodimers and heterodimers of AO subunits. Transcripts expressed at high levels in developing siliques and at low levels in dry seeds. Induced by dehydration, in rosette leaves but not in roots (PubMed:10972874, PubMed:28188272). Induced by hydrogen peroxide H(2)O(2) and aldehyde treatment (PubMed:28188272). Plants have normal abscisic acid (ABA) levels, normal germination and are not affected in abscisic aldehyde oxidase activity in siliques, dry seeds and leaves. Reduced levels of benzoic acid (BA), 3-benzoyloxypropylglucosinolate and 4-benzoyloxybutylglucosinolate in seeds. Senesced siliques accumulate high endogenous reactive carbonyl species (RCS) levels associated with enhanced senescence molecular markers, have an increased chlorophyll degradation, and exhibit early seed shattering. Severe tissue damage and enhanced malondialdehyde levels and senescence symptoms in siliques treated with several aldehydes. Increased endogenous reactive carbonyl species (RCS) and higher expression levels of senescence marker genes, leading to premature siliques senescence in response to abiotic stresses such as dark and ultraviolet C irradiation (PubMed:28188272). Belongs to the xanthine dehydrogenase family.