Teses de Mestrado ESA
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Browsing Teses de Mestrado ESA by Author "Akrimi, Amall"
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- Tocopherols (vitamin E) production and profile of mycorrhizal fungi before and after in vitro elicitation by host plant rootsPublication . Akrimi, Amall; Martins, Anabela; Ferreira, Isabel C.F.R.; Zaghdoudi, KhalilMycorrhizal fungi are symbiotic organisms that establish associations with the root system of plants. This special form of living implicates a recognizing process where chemical signals are involved, and oxidative stress mechanisms are most probably activated and overcome. Thus, during this process there is the release of compounds from the secondary metabolism, characterized by their bioactive potential and, therefore, compounds of interest. Tocopherols, vitamin E vitamers, are some of the molecules released during the oxidative stress process. Actually, vitamin E is the common name for a group of compounds which includes tocopherols and tocotrienols, lipophilic antioxidant compounds with important effects on the body, including aging prevention, immune system strengthening and cancer risk reduction. Mushrooms have been reported as a source of different antioxidants, among which are tocopherols. In order to better understand the establishment of the mycorrhizal symbiosis and to promote the production of compounds of interest, namely tocopherols, two species of mycorrhizal mushrooms (Clitocybe odora (Bull.) P. Kumm. and Scleroderma polyrhizum (J.F. Gmel.) Pers.) and host plants (Castanea sativa Mill.) were studied separately and in co-culture. The aim of the present work was: i) evaluate tocopherols composition of mycorrhizal mushrooms from different species/ecosystems; ii) assess tocopherols production of in vitro isolated and grown mycelia of the studied species; and iii) analyse tocopherols production of in vitro grown mycelia before and after co-culture by host roots, evaluating the effect of host root on the production and profile of tocopherols. After co-culture of both mushroom species with Castanea sativa roots, the tocopherols profile of the three species was determined by high performance liquid chromatography coupled to a fluorescence detector (HPLC-FL). The results obtained showed that the studied species produce rare vitamers of tocopherol, but this mycorrhizal relationship does not cause any oxidative stress for mushrooms or roots, hence the drop in the amount of the different vitamers after the coculture.