GmcA Is a Putative Glucose-Methanol-Choline Oxidoreductase Required for the Induction of Asexual Development in <em>Aspergillus nidulans</em>

<div><p><em>Aspergillus nidulans</em> asexual differentiation is induced by Upstream Developmental Activators (UDAs) that include the bZIP-type Transcription Factor (TF) FlbB. A 2D-PAGE/MS-MS-coupled screen for proteins differentially expressed in the presence and absence of FlbB identified 18 candidates. Most candidates belong to GO term classes involved in osmotic and/or oxidative stress response. Among these, we focused on GmcA, a putative glucose-methanol-choline oxidoreductase which is upregulated in a Δ<em>flbB</em> background. GmcA is not required for growth since no differences were detected in the radial extension upon deletion of <em>gmcA</em>. However, its activity is required to induce conidiation under specific culture conditions. A Δ<em>gmcA</em> strain conidiates profusely under acid conditions but displays a characteristic <em>fluffy</em> aconidial phenotype in alkaline medium. The absence of asexual development in a Δ<em>gmcA</em> strain can be suppressed, on one hand, using high concentrations of non-fermentable carbon sources like glycerol, and on the other hand, when the cMyb-type UDA TF <em>flbD</em> is overexpressed. Overall, the results obtained in this work support a role for GmcA at early stages of conidiophore initiation.</p>