Hydrogen sulphide and signalling in plants

The electronic version of this article is the definitive one. It is located here: http://www.cabi.org/cabreviewsSeveral 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

Lipid peroxidation levels in soybean (Glycine max (L.) Merr.) seed parts as a consequence on imbibition stress

High rainfall and rapid water uptake by dry seed after sowing in the field can result in so-called seed imbibitional damage. Here, lipid peroxidation levels were evaluated in seed testa, embryos and cotyledons of three soybean cultivars (Podravka 95, Tisa and Vita), after 3, 6, 12 and 24 h of seed imbibition in water at 20oC. In general, lipid peroxidation was enhanced in soybean embryos and the lowest vales were observed in seed testa. With respect to imbibition duration, the highest lipid peroxidation was observed after 3 h of imbibition and decreased thereafter in seed of Podravka 95 and Vita, with similar trend regarding seed of the same age

Hydrogen sulfide: Environmental factor or signalling molecule?

Hydrogen sulfide (H2S) has traditionally been thought of as a phytotoxin, having deleterious effects on the plant growth and survival. It is now recognized that plants have enzymes which generate H2S, cysteine desulfhydrase, and remove it, O-acetylserine lyase. Therefore, it has been suggested that H2S is considered as a signalling molecule, alongside small reactive compounds such as hydrogen peroxide (H2O2) and nitric oxide (NO). Exposure of plants to low of H2S, for example from H2S donors, is revealing that many physiological effects are seen. H2S seems to have effects on stomatal apertures. Intracellular effects include increases in glutathione levels, alterations of enzyme activities and influences on NO and H2O2 metabolism. Work in animals has shown that H2S may have direct effects on thiol modifications of cysteine groups, work that will no doubt inform future studies in plants. It appears therefore, that instead of thinking of H2S as a phytotoxin, it needs to be considered as a signalling molecule that interacts with reactive oxygen species and NO metabolism, as well as having direct effects on the activity of proteins. The future may see H2S being used to modulate plant physiology in the field or to protect crops from postharvest spoilage. This paper highlights the effects of hydrogen sulfide on plants, and discusses the evidence that this gas can be considered as a signalling molecule. Plants can be shown to generate hydrogen sulfide and respond to it, with recent work pointing to the possibility that hydrogen sulfide may modify protein thiol groups. This would mean that hydrogen sulfide may be in competition with reactive oxygen species and nitric oxide in its potential signalling role. © 2013 John Wiley & Sons Ltd

Hydrogen sulfide effects on stomatal apertures

Hydrogen sulfide (H(2)S) has recently been reported to be a signaling molecule in plants. It has been well established that is has such roles in animals and it has been suggested that it is included into the group of gasotransmitters. We have recently shown that hydrogen sulfide causes stomatal opening in the model plant Arabidopsis thaliana. H(2)S can be supplied to the plant tissues from donors such as sodium hydrosulfide (NaSH) or more recently from slow release H(2)S donor molecules such as GYY4137. Both give similar effects, that is, they cause stomatal opening. Furthermore both H(2)S donors reduced the accumulation of nitric oxide (NO) induced by abscisic acid (ABA) treatment of leaf tissues. Here similar work has been repeated in a crop plant, Capsicum anuum, and similar data has been obtained, suggesting that such effects of hydrogen sulfide on plants is not confined to model species

Antioxidative responses in radish (Raphanus sativus L.) plants stressed by copper and lead in nutrient solution and soil

Radish (Raphanus sativus L.) is commonly grown in urban and suburban areas where the soil may be polluted with heavy metals such as Cu or Pb. In this study, short exposure of radish plantlets to 0.5 mM Cu or Pb in nutrient solution (two days) in growth chamber conditions elicited an antioxidative response, measured in terms of lipid peroxidation, protein and proline accumulation, and peroxidase and catalase activity. Longer exposure to Cuor Pb when radish was grown outdoors for 50 days in pots filled with field soil with different Cu and Pb contentalso resulted in higher lipid peroxidation and proline accumulation, and altered protein content and enzyme activity. The tested parameters of radish antioxidative responses to heavy metal stress differed depending on plant part(leaf or hypocotyl) and stress intensity (heavy metal content in growth medium, exposure duration). The reporteddata show that plants grown in soil from sites where this crop could be cultivated do show an oxidative stressresponse similar but not identical to that seen under laboratory treatment with heavy metals