Naslov
Cell redox bilance, lipid metabolism and aflatoxin biosynthesis in Aspergillus sect. Flavi.

Autori
Reverberi, Massimo ; Punelli, Marta ; Smith, Carie ; Punelli, Federico ; Zjalic, Slaven ; Ricelli, Alessandra ; Payne, Gary ; Fabbri, Anna Adele ; Fanelli, Corrado

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Journal of Plant Pathology / - , 2007, S21-S21

Skup
XIV Congresso Nazionale della Società Italiana di Patologia Vegetale

Mjesto i datum
Perugia, Italija, 18.09.2007. - 21.09.2007

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
aflatoxins ; maize ; oxidative stress ; lipoperoxidation

Sažetak
In Aspergillus parasiticus, oxidative stress produced during conidia germination and fungal growth, regulate aflatoxin synthesis via the expression of the oxidative stress-related transcription factor Apyap1 which promotes the antioxidant defence response of the fungal cell. In A. flavus and A. parasiticus a gene cluster for sugar utilisation (SU) has been found which is co-regulated together with the aflatoxin gene cluster. Many fungal toxins, among which aflatoxins, are members of a large, diversified class of compounds known collectively as polyketides. Acetyl-CoA, both as polyketide starter unit and extender unit via malonyl-CoA formation, is the fundamental building block of most fungal polyketides. The nadA gene, present in the SU cluster, encodes NADH oxidase, an enzyme involved in the conversion of pyruvate to Acetyl-CoA and controlling the NAD/NADH ratio through the utilisation of O2present in the cell. Since A. flavus infects primarily the embryo and aleurone layer of maize seeds, which are known to house the majority of seed lipids in this plant, it can be argued that theb-oxidation of seed fatty acids, activated during the infection processes, can supply the aflatoxin building blocks, i.e. the Acetyl-CoA. Further, during maize infection, ROS seems to drive aflatoxin synthesis in A. parasiticus, generating an endogenous eroxidant state.A scenario emerges that leads us to hypothesise that the Acetyl-CoA present in the cell, controlled also by NADH oxidase, supplies the building blocks necessary for toxin synthesis that occurs only in the presence of a hyperoxidant state of the cel.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Biotehnologija

POVEZANOST RADA