An efficient heterologous Escherichia coli-based expression system for lectin production from Pleurocybella porrigens

RNA-Seq analysis of the fruiting bodies and mycelia of angel-wing mushroom Pleurocybella porrigens that cause acute encephalopathy

OBJECTIVE

In 2004, after consuming angel-wing mushrooms, Pleurocybella porrigens, 59 incidents of food poisoning were reported in Japan. Consequently, 17 individuals died of acute encephalopathy. In 2023, we proved that a lectin, pleurocybelline, and pleurocybellaziridine from this mushroom caused damage to the brains of mice. Although we reported genomic and transcriptomic data of P. porrigens in 2013, the assembly quality of the transcriptomic data was inadequate for accurate functional annotation. Thus, we obtained detailed transcriptomic data on the fruiting bodies and mycelia of this mushroom using Illumina NovaSeq 6000.

RESULTS

De novo assembly data indicated that the N50 lengths for the fruiting bodies and mycelia were improved compared with those previously reported. The differential expression analysis between the fruiting bodies and the mycelia revealed that 1,937 and 1,555 genes were significantly up-regulated in the fruiting bodies and the mycelia, respectively. The biological functions of P. porrigens transcripts, including PA biosynthetic pathways, were investigated using BLAST search, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathway analysis. The obtained results revealed L-valine, a predicted precursor of PA, is biosynthesized in the fruiting bodies and mycelia. Furthermore, real-time RT-PCR was performed to evaluate the accuracy of the results of differential expression analysis.

Chemical elucidation of acute encephalopathy by ingestion of angel-wing mushroom (Pleurocybella porrigens) - involvement of three constituents in onset

The mushroom, Pleurocybella porrigens, is widely consumed in Japan; however, in autumn 2004, acute encephalopathy due to ingestion of the mushroom in a large group of patients was reported in Japan. We have continued working on the mushroom to clarify the mechanisms underlying the acute encephalopathy that occurred due to its consumption. The data collected to date have shown that three compounds, pleurocybelline (PC), a Pleurocybella porrigens lectin (PPL), and pleurocybellaziridine (PA), in the mushroom are potentially responsible for the onset of the disease; PC that exhibit lethal activity in mice and PPL formed a complex, and the complex of the two components exhibited proteolytic activity and disrupted the blood-brain barrier. Although PA was not isolated directly from the mushroom, the existence of this compound in the mushroom was predicted. The compound was chemically synthesized and its endogeneity in the mushroom was demonstrated. Furthermore, PA exhibited toxicity to oligodendrocytes.