Abstract: Objective: In order to overcome the deficiency of the traditional method to toxin-producing fungi, the toxin biosynthetic pathways and related key genes in Penicillium citrinum YL-1 were investigated by genomics to evaluate the safety of P. citrinum YL-1 during fish sauce fermentation. Methods: The strain was identified by internal transcribed spacer (ITS) sequencing. Genome survey of strain YL-1 was performed using the Illumina Hiseq platform. The key synthetic pathways and genes involved in the synthesis of Penicillium toxin and aflatoxin, as well as mycotoxin metabolism in which strain YL-1 may be involved were analyzed. The metabolic pathways of non-ribosomal peptide synthetase (NRPS), polyketide synthase (PKS), PKS-NRPS, terpenoid and amino acids and related genes were analyzed by bioinformatics tools. The mycotoxin-producing ability of YL-1 was determined to evaluate whether there was a potential hazard of mycotoxin. Results: Strain YL-1 was identified as P. citrinum with a 99% similarity. The genome of P. citrinum YL-1 was 31.92 Mb in length with GC content of 46.27%. A total of 11 980 genes were predicted using Maker2 sequencing by homology analysis, including 5 417 eukaryotic genes and 4 946 prokaryotic genes annotated in eukaryote clusters of orthologous groups (KOG) and cluster of orthologous groups of proteins (COG) databases, respectively. Kyoto Encyclopaedia of Genes and Genomes (KEGG) analysis was used to assign 3 525 genes to 323 pathways. Five metabolic pathways related to the biosynthesis of mycotoxins were annotated in P. citrinum YL-1, including only one homologous gene (Afld) involved in the metabolic pathway of aflatoxin and five other related genes. However, no complete metabolic pathway was annotated. Conclusion: Despite the above findings, further studies should be done to evaluate the safety of P. citrinum YL-1 in fish sauce and other related products.

Key words: Penicillium citrinum YL-1, mycotoxins, safety, genomic sequence