The effects of point mutations in the CcsA- and Syn2 A domains on product formation.

<p>The chromatograms show BPCs of <i>A</i>. <i>nidulans</i> extracts expressing various single- and double mutations in the NRPS A domain as specified above the traces. EICs for niduclavin and niduporthin are highlighted in blue. A) Expression of CcsA containing single- and double point mutations (E3334S and C3388G). B) Expression of Syn2 containing single- and double point mutations (S3381E and G3435C). Only niduporthin-production by Syn2 was affected by introduction of the mutations.</p

Deletion of the green pigment gene UA08_00425 in <i>Talaromyces atroroseus</i> using CRISPR-Cas9.

<p>A-C) Plates resulting from co-transformation of pD-hyg-UA08_00425 and CRISPR-Cas9 vectors carrying three different protospacers, protospacer 1–3, respectively. D) <i>T</i>. <i>atroroseus</i> transformed with gene-targeting plasmid pD-hyg-UA08_00425 (pFC574) in the absence of a CRISPR-Cas9 vector. E) <i>T</i>. <i>atroroseus</i> transformed with an AMA1-based plasmid containing the hygromycin resistance marker <i>hph</i>. F) Three-point inoculation of UA08_00425Δ <i>T</i>. <i>atroroseus</i> growing on CYA.</p

Four structurally similar polyketide-nonribosomal peptide products.

<p>Niduclavin (A) and niduporthin (B) are two novel hybrid products produced by heterologous expression of two related PKS-NRPSs in <i>Aspergillus nidulans</i> [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169712#pone.0169712.ref009" target="_blank">9</a>], while ZG-1494α/talaroconvolutin B (C) and talaroconvolutin A (D) are produced in <i>Talaromyces atroroseus</i>.</p

Overexpression of <i>syn2</i> and <i>rap2</i> in <i>A</i>. <i>nidulans</i> leads to production of niduporthin.

<p>A) The structure of niduporthin, elucidated by NMR spectrocopy, B) BPC of <i>A</i>. <i>nidulans</i> extracts, showing production of niduporthin (EIC @ <i>m/z</i> 427.2380 highlighted in blue), and C) BPC of reference strain, which displayed no production of niduporthin.</p

Linker-modified variants of CcsA and Syn2^a.

<p>Linker-modified variants of CcsA and Syn2<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161199#t001fn001" target="_blank">^a</a>.</p

Analysis of chimeric variants of PKS-NRPSs CcsA and Syn2.

<p>The chromatograms show BPCs of <i>A</i>. <i>nidulans</i> extracts expressing PKS-NRPS hybrid compounds. EICs of the products are highlighted in blue along with structures of the predicted compounds: A) Expression of chimeric <i>ccsA-syn2</i> leads to production of niduchimaeralin A (m/z 455.2693). B) Expression of chimeric <i>syn2-ccsA</i> leads to production of niduchimaeralin B (m/z 388.2271). c) Reference strain.</p

Structures of known PKS-NRPS products [5–9].

<p>Structures of known PKS-NRPS products [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161199#pone.0161199.ref005" target="_blank">5</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161199#pone.0161199.ref009" target="_blank">9</a>].</p

Overexpression of <i>ccsA</i> and <i>ccsC</i> in <i>A</i>. <i>nidulans</i> leads to production of niduclavin.

<p>A) The structure of niduclavin, elucidated by NMR spectrocopy, B) Base peak chromatogram (BPC) of <i>A</i>. <i>nidulans</i> extracts, showing production of niduclavin (extracted ion chromatogram (EIC) @ <i>m/z</i> 416.2584 highlighted in blue), and c) BPC of reference strain, which displayed no production of niduclavin.</p

The <i>A. terreus</i> transcription factor GedR is important for gene expression in the geodin gene cluster in <i>A. nidulans</i>.

<p>Transcription levels of selected <i>ged</i>-genes in <i>ged</i>⁺<i>mdpA-L</i>Δ, <i>gedR</i>Δ strains relative to the corresponding levels in <i>ged</i>⁺<i>mdpA-L</i>Δ strains.</p

Summary of characterized and putative ORFs in the <i>A. terreus</i> geodin gene cluster.

<p>All similarity percentages indicate identities at the amino acid level.</p>*<p>One of these three putative ORFs is likely to encode the emodin O-methyltransferase described by Chen et al <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0072871#pone.0072871-Chen2" target="_blank">[16]</a>.</p