Genome-Based Analysis of Aspergillus niger Aggregate Species from China and Their Potential for Fumonisin B2 and Ochratoxin A Production.

Based on entire genome sequencing, this study focused on the classification of Aspergillus niger aggregation species and investigated their potential for fumonisin B2 (FB2) and ochratoxin A (OTA) production. In the current study, 22 strains were used, namely 17 A. niger strains, four A. welwitschiae strains, and one A. lacticoffeatus (a synonym of A. niger) strain. Traditional multigene phylogenetic analysis, average nucleotide identity analysis (ANI), and the whole-genome single-nucleotide polymorphism (SNP) analyses were used to reconfirm the taxonomic status of A. niger, A. welwitschiae, and A. lacticoffeatus. The ability of A. niger to produce FB2 and OTA on five culture substrates was determined, and the association between FB2 and OTA gene clusters and toxin-producing abilities was explored. The results revealed that the ANI method could distinguish A. niger from A. welwitschiae, with an ANI value of < 98%. The SNP-based phylogenetic analysis suggested that A. niger and A. welwitschiae were two independent phylogenetic species. The ANI, SNP, and multigene phylogenetic analysis supported previous findings that A. lacticoffeatus was a synonymous species of A. niger. Aspergillus niger strains exhibited the varied potential of producing FB2 and OTA on different culture media. The A. niger genome sequence analysis revealed no significant difference in fumonisin gene clusters between FB2-nonproducing isolates and FB2-producing isolates, and the integrity of the ochratoxin biosynthesis genes cluster was clearly associated with OTA production. In conclusion, gene sequencing can be useful in assessing A. niger's ability to produce OTA, but it cannot reliably predict its ability to produce FB2.

Mucor rongii sp. nov., a New Cold-Tolerant Species from China.

Two strains of a new mucoralean fungus (M1 and R1) were harvested from the moist walls of Sufu workshop in Liaocheng city, Shandong province, China. Internal transcribed spacer (ITS) and the large subunit (LSU) rDNA region D1/D2 domain-based phylogenetic analysis, along with phenotypic characteristics, revealed that the strains belonged to a new genus in the Mucor category. This new category belongs to Mucor flavus complex. However, unlike M. flavus CBS 234.25 (the type species of the complex), the novel species could grow well at 25 °C and not grow at 28 °C. Moreover, the ITS rDNA sequence similarity of the two species was only 96%. Here, we present the new category Mucor rongii sp. nov. Its holotype is HMAS 248,091, the ex-type culture is M1T (= CICC 41725T), and the other culture examined was R1 (= CICC 41,726).

Extraction and antioxidant activity of total triterpenoids in the mycelium of a medicinal fungus, Sanghuangporus sanghuang.

The scientific name of the traditional Chinese medicinal fungus, Sanghuang, has been clarified and confirmed that it is a new species -Sanghuangporus sanghuang in the recently discovered genus, Sanghuangporus. To maximize the yield of the active ingredients such as the triterpenoids from authentic Sanghuangporus sanghuang, four parameters of the extraction process, including the extraction time, solid-liquid ratio, extraction temperature, and ethanol concentration were determined. The Box-Behnken experimental design and the response surface method were used to optimize the triterpenoid extraction processes of Sanghuangporus sanghuang mycelium. The results showed that the parameters of the triterpenoid extraction processes were not simple linear relationships. Optimum conditions of ultrasonic extraction required an 80% ethanol concentration, a 1:20 solid-liquid ratio, a 20-min extraction time, and a 60 °C extraction temperature, to obtain a maximum triterpenoid extraction of 13.30 mg/g. Antioxidant capacity tests showed that the Sanghuangporus sanghuang triterpenoids had high clearance capabilities for hydroxyl free radicals, superoxide anions, 2,2-diphenyl-1-picrylhydrazyl free radicals, and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) radicals, indicating that the Sanghuangporus sanghuang triterpenoids had high antioxidant activities.