SUPEROXIDE DISMUTASE – MUSHROOMS UNDER STRESS!
Recently, a library of genes up-regulated during senescence has been produced and a stress-adaptation gene identified. Both the cDNA and the genomic DNA for superoxide dismutase has been fully sequenced and comparisons of the derived protein sequence with databases confirm its identity with very high probability. Post-harvest, the superoxide dismutase gene is up- regulated in Agaricus bisporus sporophores. The role of superoxide dismutase is to act as a free radical scavenger preventing oxidative damage. Stresses facing plant and fungi can be classed as abiotic or biotic. Abiotic stresses include heat, chilling, freezing, light, salinity, drought and ozone whereas biotic stresses are those imposed by wounding, pests and pathogens. Most abiotic and biotic stresses lead directly or indirectly to the production of free radicals and reactive oxygen species. This can be classed as oxidative stress. The secondary effects of abiotic stress is the production of reactive oxygen species. Superoxide dismutase is involved in the dismutation of superoxide radicals to produce reactive oxygen species which can be damaging to cellular function and membranes. Agaricus bisporus possesses an iron/manganese-type superoxide dismutase gene which is up- regulated following harvest. The advantage to a harvested mushroom of having greatly elevated transcript levels of superoxide dismutase is that it is potentially able to respond rapidly to potentially lethal levels of superoxide radicals and the significance of these observations for improved post-harvest quality. Expression studies have been carried out to examine levels of gene transcripts over time (post-harvest) and in different tissues.
This work is carried out in collaboration with Dr Janey Henderson (Coventry University)
Contact
Dr Kerry Burton (kerry.burton@warwick.ac.uk)
Dr Dan Eastwood (daniel.eastwood@warwick.ac.uk)
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