Role for reductase in ROS resistance?

Water deficit is already the major abiotic factor that affects crop productivity worldwide and as the effects of global climate change become more intense, things can only get worse (misquoting a well-known song). Work on drought-response mechanisms, such as that carried out by Contour-Ansel et al. (Universite` Paris 12, pp. 1279–1287), is therefore very important. The authors have focused on glutathione reductase (GR), an enzyme involved both in maintaining the pool of reduced glutathione (GSH) and in protection against reactive oxygen species (ROS). Drought-tolerant and non-tolerant cultivars of cowpea (Vigna unguiculata) were exposed to drought by withholding water; leaves were desiccated by air drying. Changes in leaves of the levels of mRNAs encoding the cytosolic and the organellar GRs were assayed by RT–PCR. In the drought-tolerant cultivar, progressive drought of whole plants led to a decrease in the expression of the organellar GR and an increase in the expression of cytosolic GR. In the non-tolerant cultivar, expression of both genes increased. In air-dried leaves, the tolerant cultivar exhibited no overall change in expression of the organellar GR whereas the expression of cytosolic GR increased, as already seen in whole plants. In the non-tolerant cultivar, it was expression of the organellar form that increased. Application of

Professor J. A. Bryant
University of Exeter, UK
j.a.bryant{at}exeter.ac.uk