Comparative Transcriptome Analysis of Penicillium citrinum Cultured with Different Carbon Sources Identifies Genes Involved in Citrinin Biosynthesis

Abstract

Citrinin is a toxic secondary metabolite of Penicillium citrinum and its contamination in many food items has been widely reported. However, research on the citrinin biosynthesis pathway and its regulation mechanism in P. citrinum is rarely reported. In this study, we investigated the effect of different carbon sources on citrinin production by P. citrinum and used transcriptome analysis to study the underlying molecular mechanism. Our results indicated that glucose, used as the sole carbon source, could significantly promote citrinin production by P. citrinum in Czapek’s broth medium compared with sucrose. A total of 19,967 unigenes were annotated by BLAST in Nr, Nt, Swiss-Prot and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Transcriptome comparison between P. citrinum cultured with sucrose and glucose revealed 1085 differentially expressed unigenes. Among them, 610 were upregulated while 475 were downregulated under glucose as compared to sucrose. KEGG pathway and Gene ontology (GO) analysis indicated that many metabolic processes (e.g., carbohydrate, secondary metabolism, fatty acid and amino acid metabolism) were affected, and potentially interesting genes that encoded putative components of signal transduction, stress response and transcription factor were identified. These genes obviously had important impacts on their regulation in citrinin biosynthesis, which provides a better understanding of the molecular mechanism of citrinin biosynthesis by P. citrinum.

Elevated CO2 delays the early development of scleractinian coral Acropora gemmifera

“…Clean reads of each treatment were mapped to reference genes transcriptome generated by total de novo RNA-seq 52 , 53 . The gene expression level was calculated by the value of FPKM (Fragments Per Kilobase of transcript per Million).…”

“…The gene expression level was calculated by the value of FPKM (Fragments Per Kilobase of transcript per Million). The differentially expressed genes were annotated using GO and KEGG enrichment analyses according to a method similar to that described by 52 , 53 . The best BLAST hit was used to assess differential gene expression, which was estimated with log 2 fold change.…”

Impact of veA on the development, aggressiveness, dissemination and secondary metabolism of Penicillium expansum

“…A gene encoding a specific transcription factor, often located inside the cluster, activates all the genes in each cluster: patL ( P. expansum ) (Ballester et al ., ; Snini et al ., ) and mrl3 / ctnA ( P. citrinum/P. expansum ) (He and Cox, ; Li et al ., ) for patulin and citrinin clusters, respectively. Bioinformatics analysis has shown that the genome of P. expansum contains other identified or predicted clusters of secondary metabolites (Ballester et al ., ; Nielsen et al ., ).…”

Complete mitochondrial genome and phylogenetic analysis of Penicillium citrinum in dark tea

“…Penicillium citrinum is a filamentous fungus within the genus Penicillium. Its widely distributed and can grow in fruits, grains (Houbraken et al 2010) and tea (Dutta et al 2010;Haas et al 2013); it can produce mycotoxin citrinin under certain conditions (Li et al 2017), which has adverse effects on human kidney and immune system (Aiko and Mehta 2013; F€ ollmann et al 2014). The present study reported the complete mitochondrial genome sequence of a P. citrinum isolated from dark tea, providing important information for population genetics, evolution and taxonomy of this fungus.…”