Sulfite oxidase protects plants against sulfur dioxide toxicity.

The gaseous pollutant SO(2) readily reacts with water to form sulfite that impacts deleteriously on animal and plant health. By modulating the level of sulfite oxidase (SO) that catalyzes the transformation of sulfites to the non-toxic sulfate, we show that Arabidopsis and tomato plants can be rendered resistant or susceptible to SO(2)/sulfite. Plants in which sulfite oxidase expression was abrogated by RNA interference (RNAi) accumulated relatively less sulfate after SO(2) application and showed enhanced induction of senescence and wounding-associated transcripts, leaf necrosis and chlorophyll bleaching.

The plant Mo-hydroxylases aldehyde oxidase and xanthine dehydrogenase have distinct reactive oxygen species signatures and are induced by drought and abscisic acid.

The plant molybdenum-cofactor (Moco) and flavin-containing enzymes, xanthine dehydrogenase (XDH; EC 1.2.1.

Plant respiratory burst oxidase homologs impinge on wound responsiveness and development in Lycopersicon esculentum.

Plant respiratory burst oxidase homologs (Rboh) are homologs of the human neutrophil pathogen-related gp91(phox). Antisense technology was employed to ascertain the biological function of Lycopersicon esculentum (tomato) Rboh. Lines with diminished Rboh activity showed a reduced level of reactive oxygen species (ROS) in the leaf, implying a role for Rboh in establishing the cellular redox milieu.