Whole-genome assembly and analysis of a medicinal fungus: Inonotus hispidus

Structural characterization, chain conformation and immunomodulatory activity of a heteropolysaccharide from Inonotus hispidus

A new polysaccharide (IHP-1aa) was isolated from the fruiting body of Inonotus hispidus by hot water extraction, ethanol precipitation and column chromatography. The molecular weight of IHP-1aa was 26.9 kDa. Structural analysis showed that IHP-1aa consisted of glucose (Glc), galactose (Gal), fucose (Fuc), mannose (Man) and contained a certain amount of 3-O-methylgalactose (3-O-Me-Gal). The structure was mainly composed of →6)-α/β-D-Glcp-(1→, →6)-α-D-Galp-(1→, →6)-(3-O-Me)-α-D-Galp-(1→, →6)-α-D-Manp-(1 → and →2, 6)-α-D-Galp-(1 → as the main chain. Branched at O-2 with single β-L-Fucp-(1 → 6)-α-D-Galp-(1 → 6)-α-D-Glcp-(1 → as major the side chain. The results of SEM, XRD and AFM combined with Congo red indicated that IHP-1aa may be amorphous granular chain conformation. In addition, IHP-1aa stimulated macrophage function and improved phagocytic ability of RAW264.7, as well as promoted the secretion of NO, TNF-α and IL-6. IHP-1aa, a 3-O-methylgalactose-containing heteropolysaccharide, was isolated for the first time from the I. hispidus, which may be used as a potential immunomodulator in functional foods.

Genomic comparison between two Inonotus hispidus strains isolated from growing in different tree species

Inonotus hispidus mainly growing in broad-leaved trees, including Morus alba, Fraxinus mandshurica, and Ulmus macrocarpa etc. The fruiting body of I. hispidus growing in M. alba (hereafter as MA) is used as a traditional Chinese medicine "Sanghuang". However, differences between the genetic material basis of I. hispidus growing in other tree species have not been reported. Therefore, in this paper, the genomic comparison between MA and I. hispidus growing in F. mandshurica (hereafter as FM) were studied. The whole genome of MA monokaryon was sequenced by Illumina combined with Pac Bio platform. Next, genome assembly, genome component prediction and genome functional annotation were performed. Comparative genomics analysis was performed between FM monokaryon and MA monokaryon, using MA as the reference. The results showed that, MA had 24 contigs with a N50 length of 2.6 Mb. Specifically, 5,342, 6,564, 1,595, 383 and 123 genes were annotated from GO, KEGG, KOG, CAZymes and CYP450, respectively. Moreover, comparative genomics showed that, the coding genes and total number of genes annotated in different databases of FM were higher than that of MA. This study provides a foundation for the medicinal application of FM as MA from the perspective of genetic composition.

Whole Genome Sequence of an Edible Mushroom Oudemansiella raphanipes (Changgengu)

Oudemansiella raphanipes, considered as a well-known culinary edible mushroom with a high content of natural bioactive substances, is widely cultivated in China with the commercial name Changgengu. However, due to the lack of genomic data, molecular and genetic study on O. raphanipes is rare. To obtain a comprehensive overview of genetic characteristics and enhance the value of O. raphanipes, two mating-compatible monokaryons isolated from the dikaryon were applied for de novo genome sequencing and assembly using Nanopore and /or Illumina sequencing platforms. One of the monokaryons, O. raphanipes CGG-A-s1, was annotated with 21,308 protein-coding genes, of which 56 were predicted to be involved in the biosynthesis of secondary metabolites such as terpene, type I PKS, NRPS, and siderophore. Phylogenetic and comparative analysis of multiple fungi genomes revealed a close evolutionary relationship between O. raphanipes and Mucidula mucid based on single-copy orthologous protein genes. Significant collinearity was detected between O. raphanipes and Flammulina velutipes on the synteny of inter-species genomes. 664 CAZyme genes in CGG-A-s1 were identified with GHs and AAs families significantly elevated when compared with the other 25 sequenced fungi, indicating a strong wood degradation ability. Furthermore, the mating type locus analysis revealed that CGG-A-s1 and CGG-A-s2 were conserved in the gene organization of the mating A locus but various in that of the mating B locus. The genome resource of O. raphanipes will provide new insights into its development of genetic studies and commercial production of high-quality varieties.