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Functions and regulation of the Nox family in the filamentous fungus Podospora anserina : a new role in cellulose degradation
Author(s) -
Brun Sylvain,
Malagnac Fabienne,
Bidard Frédérique,
Lalucque Hervé,
Silar Philippe
Publication year - 2009
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2009.06878.x
Subject(s) - podospora anserina , biology , filamentous fungus , fungus , degradation (telecommunications) , cellulose , microbiology and biotechnology , biochemistry , botany , gene , mutant , telecommunications , computer science
Summary NADPH oxidases are enzymes that produce reactive oxygen species. Studies in mammals, plants and fungi have shown that they play important roles in differentiation, defence, host/pathogen interaction and mutualistic symbiosis. In this paper, we have identified a Podospora anserina mutant strain impaired for processes controlled by PaNox1 and PaNox2, the two Nox isoforms characterized in this model ascomycete. We show that the gene mutated is PaNoxR , the homologue of the gene encoding the regulatory subunit p67 phox , conserved in mammals and fungi, and that PaNoxR regulates both PaNox1 and PaNox2. Genome sequence analysis of P. anserina reveals that this fungus posses a third Nox isoform, PaNox3, related to human Nox5/Duox and plant Rboh. We have generated a knock‐out mutant of PaNox3 and report that PaNox3 plays a minor role in P. anserina , if any. We show that PaNox1 and PaNox2 play antagonist roles in cellulose degradation. Finally, we report for the first time that a saprobic fungus, P. anserina , develops special cell structures dedicated to breach and to exploit a solid cellulosic substrate, cellophane. Importantly, as for similar structures present in some plant pathogens, their proper differentiation requires PaNox1, PaNox2, PaNoxR and the tetraspanin PaPls1.