Diversity and toxigenicity of fungi and description of Fusarium madaense sp. nov. from cereals, legumes and soils in north-central Nigeria

Abstract

Mycological investigation of various foods (mainly cowpea, groundnut, maize, rice, sorghum) and agricultural soils from two states in north-central Nigeria (Nasarawa and Niger), was conducted in order to understand the role of filamentous fungi in food contamination and public health. A total of 839 fungal isolates were recovered from 84% of the 250 food and all 30 soil samples. Preliminary identifications were made, based on macro- and micromorphological characters. Representative strains (n = 121) were studied in detail using morphology and DNA sequencing, involving genera/species-specific markers, while extrolite profiles using LC-MS/MS were obtained for a selection of strains. The representative strains grouped in seven genera (Aspergillus, Fusarium, Macrophomina, Meyerozyma, Neocosmospora, Neotestudina and Phoma). Amongst the 21 species that were isolated during this study was one novel species belonging to the Fusarium fujikuroi species complex, F. madaensesp. nov., obtained from groundnut and sorghum in Nasarawa state. The examined strains produced diverse extrolites, including several uncommon compounds: averantinmethylether in A. aflatoxiformans; aspergillimide in A. flavus; heptelidic acid in A. austwickii; desoxypaxillin, kotanin A and paspalitrems (A and B) in A. aflatoxiformans, A. austwickii and A. cerealis; aurasperon C, dimethylsulochrin, fellutanine A, methylorsellinic acid, nigragillin and pyrophen in A. brunneoviolaceus; cyclosporins (A, B, C and H) in A. niger; methylorsellinic acid, pyrophen and secalonic acid in A. piperis; aspulvinone E, fonsecin, kojic acid, kotanin A, malformin C, pyranonigrin and pyrophen in A. vadensis; and all compounds in F. madaense sp. nov., Meyerozyma, Neocosmospora and Neotestudina. This study provides snapshot data for prediction of food contamination and fungal biodiversity exploitation.

Distribution of fungi and their toxic metabolites in melon and sesame seeds marketed in two major producing states in Nigeria

“…Among the metabolites were 16 mycotoxins and other metabolites produced by several fungal genera including, but not excluded to, Aspergillus , Alternaria , Fusarium and Penicillium . The spectrum of fungal metabolites detected in the food samples agree with the diversity of moulds recovered from the foods, except for a few classes of compounds whose fungal producers were not recovered—again, owing possibly to the limitations of the applied culture-dependent mycological analysis (Ezekiel et al 2020a ).…”

Fungal Diversity and Aflatoxins in Cereals and Cassava-Based Foods From Ondo State, Nigeria

“…Aspergillus aflatoxiformans was recovered from all the foods, but mostly in the cereals. This agrees with a previous report from Nigeria, wherein A. aflatoxiformans predominated in cereals including maize and rice [3]. Aspergillus aflatoxiformans (previously, wrongly classified as A. parvisclerotigenus), has been reported in cassava from neighbouring Benin Republic [46], as well as dried mushroom and peanuts from Nigeria [47,48].…”

“…In this study, Fusarium was not recovered from any of the food samples, which agrees with findings from two previous studies conducted in Nigeria on rice [2] and pupuru [12]. Conversely, this finding from the present study contradicts other available reports [3,34,39,40] that reported several Fusarium species in cereals including rice and maize. Penicillium was the second most predominant genus in the food samples, occurring in all the foods and mostly in maize and pupuru.…”

“…In tropical countries, e.g. Nigeria, favourable warm-to-hot climatic conditions coupled with poor pre-and post-harvest agricultural practices encourage widespread filamentous fungal contamination of cereals such as maize and rice [2][3][4] and cassava products (e.g. pupuru) [5].…”

“…Only a few studies used sequence data for identification of the fungi present on stored cereals in Nigeria. A study of the mycobiota of maize [3] applied a robust polyphasic approach, and an investigation of vended rice used sequences of the internal transcribed spacer (ITS) region [4]. However, ITS sequencing is less suitable for species-level identification of common food-related genera such as Aspergillus, Penicillium and Fusarium [10].…”