Hydrogen sulphide and signalling in plants
© CAB International 2011
Several relatively reactive compounds exist that are considered to play major roles in plant cell signalling. These include reactive oxygen species (ROS) such as hydrogen peroxide and nitric oxide (NO). Until recently, hydrogen sulphide (H2S) has commonly been thought of as a phytotoxin, but a growing body of evidence now points to the fact that H2S may also have a signalling role and that it should be ranked as an important signal alongside NO and ROS. At high concentrations, H2S will inhibit enzymes such as cytochrome oxidase. However, at lower concentrations, it may act in a more positive manner. A renewed interest in the role of 2S in biological systems has been evidenced in the results of research investigating cell signalling in both animals and plants. The growth and development of plants may be affected, for example, during the promotion of adventitious root formation. Stomatal closure has also been shown to be altered by H2S and it has been reported to be involved in the tolerance of plants to metals such as aluminium and copper. The treatment of plant cells with H2S affects cysteine and glutathione metabolism and there is a growing body of evidence to suggest that the presence of H2S may impact on oxidative stress metabolism and NO signalling. New H2S donor molecules are appearing in the literature, such as GYY4137, and with such new tools the true extent of the role of H2S in the control of plant signalling will no doubt be unravelled in the future.
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Vol. 6 (12), pp. 1 - 7