Exogenous glycine and serine promote growth and antifungal activity of Penicillium citrinum W1 from the south-west Indian Ocean.

PcPAF is a novel antifungal protein identified by our recent study, which is produced by a fungal strain Penicillium citrinum W1 isolated from a south-west Indian Ocean sediment sample. The present study identified glycine as a potential metabolite which increased the fungal growth and promoted antifungal activity. Then, GC/MS based metabolomics was used to disclose the metabolic mechanism manipulated by glycine. With the aid of unsupervised hierarchical clustering analysis and supervised orthogonal partial least-squares-discriminant analysis, the intracellular metabolite profiles were distinguished among two glycine-treated groups and control. 43 and 47 significantly varied metabolites were detected in 2.5 mM or 5 mM glycine-treated groups and involved in seven and eight pathways, respectively. Furthermore, exogenous serine, which is converted from glycine, showed the same potential as glycine did. Our findings not only identify glycine and serine as nutrients which promoted P. citrinum W1 growth and increased antifungal activity, but also highlight the way to utilize metabolomics for an understanding of metabolic mechanism manipulated by an exogenous compound.