A New Muscarine-Containing Inosperma (Inocybaceae, Agaricales) Species Discovered From One Poisoning Incident Occurring in Tropical China

Abstract

Currently, mushroom poisoning still poses a huge problem to humans' health and life globally. Poisoning incidents caused by Inosperma spp. were reported continuously in tropical China in recent years. In this study, a new poisonous Inosperma species, discovered from a poisoning incident, was described in tropical China based on morphological, molecular, and toxin detection evidence; detailed descriptions, photographs, and comparisons to closely related species were provided. For qualitative analysis, through targeted screening using ultra-high liquid chromatography triple quadrupole mass spectrometry (UPLC-MS/MS), the new species contains muscarine and no other toxins (two isoxazole derivatives, two tryptamine alkaloids, three amatoxins, and three phallotoxins). For quantitative analysis, muscarine contents in the pileus and the stipe were 2.08 ± 0.05 and 6.53 ± 1.88 g/kg, respectively.

Five new species of Inosperma from China: Morphological characteristics, phylogenetic analyses, and toxin detection

“…They detected that muscarine is not ancestral for the family as a whole, but it is a shared derived trait for an inclusive clade containing three of the seven major lineages of Inocybaceae (the Inocybe, Nothocybe, and Pseudosperma clades) and predicted that the species of the Inosperma clade lack muscarine. As an increasing number of muscarine-containing species of Inosperma have been reported in recent years (Bijeesh et al, 2020;Latha et al, 2020;Deng et al, 2021aDeng et al, , 2022, we believe that it is an important muscarine-containing genus in the family Inocybaceae.…”

“…The genus occurs on the ground, associates with vascular plants in mycorrhizal symbiosis, and is composed of more than 70 known taxa that are distributed in Africa, Asia, Australasia, Europe, and North America ( Matheny et al, 2019 ; Deng et al, 2021a ). Multigene (ITS, nrLSU, rpb2 , and mtSSU) molecular studies have confirmed that the genus is monophyletic and is classified into six major lineages, the Cervicolores clade, Maculatum clade, I. misakaense lineage, I. africanum lineage, and two Old World tropical clades ( Larsson et al, 2009 ; Pradeep et al, 2016 ; Matheny et al, 2019 ; Deng et al, 2022 ).…”

“…by Kühner (1980) , and recent studies elevated it to the genus rank ( Matheny et al, 2019 ). Currently, 12 Inosperma species have been reported from northeast, northwest, southwest, and southernmost China, five of which are new species that were recently discovered ( Fan and Bau, 2018 ; Deng et al, 2021a , b , 2022 ). Members of this genus are characterized by small- to medium-sized basidiomata, rimose to scaly pileus, even or bulbous stipe base, rubescent, or brunnescent context, often phaseoliform basidiospores, hyaline, or necropigmented basidia, thin-walled cheilocystidia, lack of pleurocystidia, and often have distinctive odors ( Matheny et al, 2019 ; Deng et al, 2021a ).…”

“…Inosperma muscarium , a new species in China, was responsible for two poisoning incidents involving seven people ( Deng et al, 2021a ). In the latest report, a new poisonous Inosperma species, I. zonativeliferum caused poisoning in 10 people ( Deng et al, 2022 ).…”

“…However, it has since been demonstrated to be psilocybin negative ( Stijve and Kuyper, 1988 ). Recently, Latha et al (2020) first reported the occurrence of muscarine in I. virosum , and Deng et al proposed three new Inosperma species from tropical China, namely, I. muscarium , I. hainanense and I. zonativeliferum , all of which are muscarine-positive ( Deng et al, 2021a , 2022 ). In addition, I. carnosibulbosum is probably a muscarine-positive species due to a recent report of poisonous cases ( Bijeesh et al, 2020 ).…”