l-Arabinose induces d-galactose catabolism via the Leloir pathway in Aspergillus nidulans

Zoltán Németh, László Kulcsár, Michel Flipphi, Anita Orosz, Maria Victoria Aguilar-Pontes, Ronald P de Vries, Levente Karaffa, Erzsébet Fekete

Onderzoeksoutput: Bijdrage aan wetenschappelijk tijdschrift/periodieke uitgaveArtikelWetenschappelijkpeer review


l-Arabinose and d-galactose are the principal constituents of l-arabinogalactan, and also co-occur in other hemicelluloses and pectins. In this work we hypothesized that similar to the induction of relevant glycoside hydrolases by monomers liberated from these plant heteropolymers, their respective catabolisms in saprophytic and phytopathogenic fungi may respond to the presence of the other sugar to promote synergistic use of the complex growth substrate. We showed that these two sugars are indeed consumed simultaneously by Aspergillus nidulans, while l-arabinose is utilised faster in the presence than in the absence of d-galactose. Furthermore, the first two genes of the Leloir pathway for d-galactose catabolism - encoding d-galactose 1-epimerase and galactokinase - are induced more rapidly by l-arabinose than by d-galactose eventhough deletion mutants thereof grow as well as a wild type strain on the pentose. d-Galactose 1-epimerase is hyperinduced by l-arabinose, d-xylose and l-arabitol but not by xylitol. The results suggest that in A. nidulans, l-arabinose and d-xylose - both requiring NADPH for their catabolisation - actively promote the enzyme infrastructure necessary to convert β-d-galactopyranose via the Leloir pathway with its α-anomer specific enzymes, into β-d-glucose-6-phosphate (the starting substrate of the oxidative part of the pentose phosphate pathway) even in the absence of d-galactose.

Originele taal-2Engels
Pagina's (van-tot)53-59
Aantal pagina's7
TijdschriftFungal Genetics and Biology
Vroegere onlinedatum26 nov. 2018
StatusGepubliceerd - feb. 2019


Duik in de onderzoeksthema's van 'l-Arabinose induces d-galactose catabolism via the Leloir pathway in Aspergillus nidulans'. Samen vormen ze een unieke vingerafdruk.

Citeer dit