Comparative Mitochondrial Genome Analysis of Two Ectomycorrhizal Fungi (Rhizopogon) Reveals Dynamic Changes of Intron and Phylogenetic Relationships of the Subphylum Agaricomycotina

Characterisation and comparative analysis of mitochondrial genomes of false, yellow, black and blushing morels provide insights on their structure and evolution

Morchella species have considerable significance in terrestrial ecosystems, exhibiting a range of ecological lifestyles along the saprotrophism-to-symbiosis continuum. However, the mitochondrial genomes of these ascomycetous fungi have not been thoroughly studied, thereby impeding a comprehensive understanding of their genetic makeup and ecological role. In this study, we analysed the mitogenomes of 30 Morchellaceae species, including yellow, black, blushing and false morels. These mitogenomes are either circular or linear DNA molecules with lengths ranging from 217 to 565 kbp and GC content ranging from 38% to 48%. Fifteen core protein-coding genes, 28-37 tRNA genes and 3-8 rRNA genes were identified in these Morchellaceae mitogenomes. The gene order demonstrated a high level of conservation, with the cox1 gene consistently positioned adjacent to the rnS gene and cob gene flanked by apt genes. Some exceptions were observed, such as the rearrangement of atp6 and rps3 in Morchellaimportuna and the reversed order of atp6 and atp8 in certain morel mitogenomes. However, the arrangement of the tRNA genes remains conserved. We additionally investigated the distribution and phylogeny of homing endonuclease genes (HEGs) of the LAGLIDADG (LAGs) and GIY-YIG (GIYs) families. A total of 925 LAG and GIY sequences were detected, with individual species containing 19-48HEGs. These HEGs were primarily located in the cox1, cob, cox2 and nad5 introns and their presence and distribution displayed significant diversity amongst morel species. These elements significantly contribute to shaping their mitogenome diversity. Overall, this study provides novel insights into the phylogeny and evolution of the Morchellaceae.

Assembly and comparative analysis of the complete mitochondrial genome of Daedaleopsissinensis (Polyporaceae, Basidiomycota), contributing to understanding fungal evolution and ecological functions

Daedaleopsissinensis is a crucial wood-decaying fungus with significant lignocellulose-degrading ability, which plays a vital role in the material cycle and energy flow of forest ecosystems. However, the mitochondrial genome of D.sinensis has not yet been revealed. In the present study, the complete mitochondrial genome of D.sinensis was assembled and compared with related species. The mitochondrial genome spans 69,155 bp and has a GC content of 25.0%. It comprises 15 protein-coding genes (PCGs), 26 transfer RNA genes, two ribosomal RNA genes and one DNA polymerase gene (dpo). Herein, we characterised and analysed the codon preferences, variation and evolution of PCGs, repeats, intron dynamics, as well as RNA editing events in the D.sinensis mitochondrial genome. Further, a phylogenetic analysis of D.sinensis and the other 86 Basidiomycota species was performed using mitochondrial genome data. The results revealed that four species, D.confragosa, D.sinensis, D.nitida and Fomesfomentarius, were grouped in a closely-related cluster with high support values, indicating that a close phylogenetic relationship existed between Daedaleopsis and Fomes. This study reported on the initial assembly and annotation of the mitochondrial genome of D.sinensis, which greatly improved the knowledge of the fungus. These results contribute to the limited understanding of the mitochondrial repository of wood-decaying fungi, thereby laying the foundation for subsequent research on fungal evolution and ecological functions.

The first complete mitochondrial genome of Phellinus pomaceus var. prunastri (Pers.) Pat. 1926 (Hymenochaetales: Hymenochaetaceae) and phylogenetic analysis

Phellinus pomaceus var. prunastri (Pers.) Pat. 1926 is a famous medicinal fungus that has attracted considerable interest in biotechnology because of its diverse biologically active ingredients. Here, we provide the full mitochondrial genome sequence of P. pomaceus, which spans 122,850 bp and has a GC content of 26.04%. The genome comprises 15 essential protein-coding genes, 26 distinct ORFs, 24 intronic ORFs, 25 tRNAs, and 2 rRNA genes. Bayesian inference (BI) was employed for phylogenetic analysis, revealing the evolutionary relationships among 17 Basidiomycota fungi. The results strongly supported distinct clades and indicated that P. pomaceus is closely related to Fomitiporia mediterranea.

Characterization of the complete mitochondrial genome of the medical fungus Ganoderma resinaceum Boud., 1889 (Polyporales: Ganodermataceae)

The medical mushroom Ganoderma resinaceum Boud., 1889, is of great interest in pharmacy due to its diverse functional active ingredients. However, the mitochondrial genome of G. resinaceum remains unexplored. Here, we present the complete mitochondrial genome of G. resinaceum, which spans 67,458 bp and has a GC content of 25.65%. This genome encompasses 15 core protein-coding genes, 8 independent ORFs, 15 intronic ORFs, 27 tRNAs, and 2 rRNA genes. Through phylogenetic analysis using Bayesian inference (BI), we elucidated the evolutionary relationships among 34 Basidiomycota fungi, revealing distinct clades and indicating a close relationship between G. resinaceum and G. subamboinense.

Characterization and phylogenetic analysis of the Talaromyces liani (kamyschko) Yilmaz, Frisvad & Samson, 2014 (Eurotiales: trichocomaceae) mitochondrial genome

The filamentous fungus Talaromyces liani (Kamyschko) Yilmaz, Frisvad & Samson, 2014, has attracted considerable interest in biotechnology due to its diverse industrial applications and physiological characteristics. However, the mitochondrial genome of T. liani remains uncharacterized. Here, we present the complete mitochondrial genome of T. liani, comprising 38,000 bp with a GC content of 24.61%. This genome includes 15 core protein-coding genes, 4 independent ORFs, 6 intronic ORFs, 26 tRNAs, and 2 rRNA genes. Phylogenetic analysis using Bayesian inference (BI) revealed the evolutionary relationships among 15 fungi from Eurotiales, strongly supporting distinct clades and indicating that T. liani most closely related to T. pinophilus.

Determining Gene Order Patterns in the Suillus and Boletales through Comparative Analysis of Their Mitogenomes

Suillus is one of the most important genera of ectomycorrhizal fungi. As a model for studying host specificity, its molecular fragments and nuclear genome have been analyzed. However, its mitochondrial genome has not yet been reported. In this study, we assembled five mitogenomes of Suillus and analyzed and compared their basic characteristics. Owing to the large number of introns as well as intergenic regions, the mitogenomic lengths of species of Suillus were greater than those of other species of Boletales. We identified two main patterns of gene order arrangement in the members of the order Boletales. The Ka/Ks values of 15 protein-coding genes were <1 for the mitochondrial genes of 39 Boletales species, indicating their conserved evolution. Phylogenetic trees, reconstructed using the mitogenomes, indicated that the genus Suillus was monophyletic. Phylogenetic results based on the internal transcribed spacer region and mitogenome were used to confirm the distribution of Suillus placidus in China. The results showed that the mitogenome was superior in distinguishing species compared with a single molecular fragment. This is the first study to investigate the mitogenome of Suillus, enriching the mitogenome information and providing basic data for the phylogeny, resource conservation, and genetic diversity of this genus.

Distinguishing Sanghuangporus from sanghuang-related fungi: a comparative and phylogenetic analysis based on mitogenomes

The Chinese medicinal fungi "Sanghuang" have been long recognized for their significant and valued medicinal properties, as documented in ancient medical literature. However, in traditional folk medicine, various macrofungi sharing similar appearance, habitat, and therapeutic effects with Sanghuang were erroneously used. These Sanghuang-like fungi mainly belong to the Porodaedalea, Phellinus, and Inonotus genera within the Hymenochaetaceae family. Despite the establishment of the Sanghuangporus genus and the identification of multiple species, the emerging taxonomic references based on morphological, ITS, and mycelial structural features have been inadequate to differentiate Sanghuangporus and Sanghuang-like fungi. To address this limitation, this study presents the first comparative and phylogenetic analysis of Sanghuang-related fungi based on mitogenomes. Our results show that Sanghuangporus species show marked convergence in mitochondrial genomic features and form a distinct monophyletic group based on phylogenetic analyses of five datasets. These results not only deepen our understanding of Sanghuang-like fungi but also offer novel insights into their mitochondrial composition and phylogeny, thereby providing new research tools for distinguishing members of the Sanghuangporus genus. KEY POINTS: • Sanghuangporus, Inonotus, and Porodaedalea are monophyly in sanghuang-like species. • Mitogenome-based analysis exhibits high resolution in sanghuang-like genus. • The mitogenomes provide strong evidence for reclassifying Phellinus gilvus S12 as Sanghuangporus vaninii.

Characterization and phylogenetic analysis of the complete mitochondrial genome of Saccharomycopsis fibuligera (lindner) Klocker 1907 (saccharomycetales: saccharomycopsidaceae)

Saccharomycopsis fibuligera (Lindner) Klocker 1907 is frequently employed in the fermentation of metabolites such as citric acid, ethanol, mannitol, and pyruvate. Its heat tolerance and alcohol-producing capabilities during fermentation make it a desirable option for bread and wine production. To date, the mitochondrial genome of S. fibuligera has not been sequenced. In the present study, we obtained the full mitochondrial genome of S. fibuligera, which is 57,302 bp long and has a GC content of 24.40%. This genome contained 14 core protein-coding genes, 3 independent ORFs, 21 intronic ORFs, 25 tRNAs, and 2 rRNA genes. By utilizing the Bayesian inference phylogenetic method, we constructed phylogenetic trees for 24 Saccharomycotina fungi, which indicated that S. fibuligera is closely related to S. capsularis.

Mitochondrial genomic characteristics and phylogenetic analysis of a brewing fungus, Rhizopus microsporus Tiegh. 1875 (Mucorales: Rhizopodaceae)

Rhizopus microsporus Tiegh. 1875 is widely used in a variety of industries, such as brewing, wine making, baking, and medicine production, as it has the capability to break down proteins and generate surface-active agents. To date, the mitochondrial genome features of early evolved fungi from the Rhizopus genus have not been extensively studied. Our research obtained a full mitochondrial genome of R. microsporus species, which was 43,837 bp in size and had a GC content of 24.93%. This genome contained 14 core protein-coding genes, 3 independent ORFs, 7 intronic ORFs, 24 tRNAs, and 2 rRNA genes. Through the use of the BI phylogenetic inference method, we were able to create phylogenetic trees for 25 early differentiation fungi which strongly supported the major clades; this indicated that R. microsporus is most closely related to Rhizopus oryzae.

Characterization of Complete Mitochondrial Genomes of the Five Peltigera and Comparative Analysis with Relative Species

In the present study, the complete mitochondrial genomes of five Peltigera species (Peltigera elisabethae, Peltigera neocanina, Peltigera canina, Peltigera ponojensis, Peltigera neckeri) were sequenced, assembled and compared with relative species. The five mitogenomes were all composed of circular DNA molecules, and their ranged from 58,132 bp to 69,325 bp. The mitochondrial genomes of the five Peltigera species contain 15 protein-coding genes (PCGs), 2 rRNAs, 26-27 tRNAs and an unidentified open reading frame (ORF). The PCG length, AT skew and GC skew varied among the 15 PCGs in the five mitogenomes. Among the 15 PCGs, cox2 had the least K2P genetic distance, indicating that the gene was highly conserved. The synteny analysis revealed that the coding regions were highly conserved in the Peltigera mitochondrial genomes, but gene rearrangement occurred in the intergenic regions. The phylogenetic analysis based on the 14 PCGs showed that the 11 Peltigera species formed well-supported topologies, indicating that the protein-coding genes in the mitochondrial genome may be used as a reliable molecular tool in the study of the phylogenetic relationship of Peltigera.

Habitat-related plastome evolution in the mycoheterotrophic Neottia listeroides complex (Orchidaceae, Neottieae)

BACKGROUND

Mycoheterotrophs, acquiring organic carbon and other nutrients from mycorrhizal fungi, have evolved repeatedly with substantial plastid genome (plastome) variations. To date, the fine-scale evolution of mycoheterotrophic plastomes at the intraspecific level is not well-characterized. A few studies have revealed unexpected plastome divergence among species complex members, possibly driven by various biotic/abiotic factors. To illustrate evolutionary mechanisms underlying such divergence, we analyzed plastome features and molecular evolution of 15 plastomes of Neottia listeroides complex from different forest habitats.

RESULTS

These 15 samples of Neottia listeroides complex split into three clades according to their habitats approximately 6 million years ago: Pine Clade, including ten samples from pine-broadleaf mixed forests, Fir Clade, including four samples from alpine fir forests and Fir-willow Clade with one sample. Compared with those of Pine Clade members, plastomes of Fir Clade members show smaller size and higher substitution rates. Plastome size, substitution rates, loss and retention of plastid-encoded genes are clade-specific. We propose to recognized six species in N. listeroides complex and slightly modify the path of plastome degradation.

CONCLUSIONS

Our results provide insight into the evolutionary dynamics and discrepancy of closely related mycoheterotrophic orchid lineages at a high phylogenetic resolution.

The first two mitochondrial genomes from Apiotrichum reveal mitochondrial evolution and different taxonomic assignment of Trichosporonales

Apiotrichum is a diverse anamorphic basidiomycetous yeast genus, and its mitogenome characterization has not been revealed. In this study, we assembled two Apiotrichum mitogenomes and compared them with mitogenomes from Agaricomycotina, Pucciniomycotina and Ustilaginomycotina. The mitogenomes of Apiotrichum gracile and A. gamsii comprised circular DNA molecules, with sizes of 34,648 bp and 38,096 bp, respectively. Intronic regions were found contributed the most to the size expansion of A. gamsii mitogenome. Comparative mitogenomic analysis revealed that 6.85-38.89% of nucleotides varied between tRNAs shared by the two Apiotrichum mitogenomes. The GC content of all core PCGs in A. gamsii was lower than that of A. gracile, with an average low value of 4.97%. The rps3 gene differentiated the most among Agaricomycotina, Pucciniomycotina and Ustilaginomycotina species, while nad4L gene was the most conserved in evolution. The Ka/Ks values for cob and rps3 genes were > 1, indicating the two genes may be subjected to positive selection in Agaricomycotina, Pucciniomycotina and Ustilaginomycotina. Frequent intron loss/gain events and potential intron transfer events have been detected in evolution of Agaricomycotina, Pucciniomycotina and Ustilaginomycotina. We further detected large-scale gene rearrangements between the 19 mitogenomes from Agaricomycotina, Pucciniomycotina and Ustilaginomycotina, and fifteen of the 17 mitochondrial genes shared by Apiotrichum varied in gene arrangements. Phylogenetic analyses based on maximum likelihood and Bayesian inference methods using a combined mitochondrial gene dataset revealed different taxonomic assignment of two Apiotrichum species, wherein A. gamsii had a more closely relationship with Trichosporon asahii. This study served as the first report on mitogenomes from the genus Apiotrichum, which promotes the understanding of evolution, genomics, and phylogeny of Apiotrichum.

Comprehensive analysis of codon bias in 13 Ganoderma mitochondrial genomes

Introduction

Codon usage bias is a prevalent phenomenon observed across various species and genes. However, the specific attributes of codon usage in the mitochondrial genome of Ganoderma species remain unknown.

Methods

In this study, we investigated the codon bias of 12 mitochondrial core protein-coding genes (PCGs) in 9 Ganoderma species, including 13 Ganoderma strains.

Results

The codons of all Ganoderma strains showed a preference for ending in A/T. Additionally, correlations between codon base composition and the codon adaptation index (CAI), codon bias index (CBI) and frequency of optimal codons (FOP) were identified, demonstrating the impact of base composition on codon bias. Various base bias indicators were found to vary between or within Ganoderma strains, including GC3s, the CAI, the CBI, and the FOP. The results also revealed that the mitochondrial core PCGs of Ganoderma have an average effective number of codons (ENC) lower than 35, indicating strong bias toward certain codons. Evidence from neutrality plot and PR2-bias plot analysis indicates that natural selection is a major factor affecting codon bias in Ganoderma. Additionally, 11 to 22 optimal codons (ΔRSCU>0.08 and RSCU>1) were identified in 13 Ganoderma strains, with GCA, AUC, and UUC being the most widely used optimal codons in Ganoderma. By analyzing the combined mitochondrial sequences and relative synonymous codon usage (RSCU) values, the genetic relationships between or within Ganoderma strains were determined, indicating variations between them. Nevertheless, RSCU-based analysis illustrated the intra- and interspecies relationships of certain Ganoderma species.

Discussion

This study deepens our insight into the synonymous codon usage characteristics, genetics, and evolution of this important fungal group.

The first two mitochondrial genomes for the genus Ramaria reveal mitochondrial genome evolution of Ramaria and phylogeny of Basidiomycota

In the present study, we assembled and analyzed the mitogenomes of two Ramaria species. The assembled mitogenomes of Ramaria cfr. rubripermanens and R. rubella were circularized, with sizes of 126,497 bp and 143,271 bp, respectively. Comparative mitogenome analysis showed that intron region contributed the most (contribution rate, 43.74%) to the size variations of Ramaria mitogenomes. The genetic contents, gene length, tRNAs, and codon usages of the two Ramaria mitogenomes varied greatly. In addition, the evolutionary rates of different core protein coding genes (PCGs) in Phallomycetidae mitogenomes varied. We detected large-scale gene rearrangements between Phallomycetidae mitogenomes, including gene displacement and tRNA doubling. A total of 4499 bp and 7746 bp aligned fragments were detected between the mitochondrial and nuclear genomes of R. cfr. rubripermanens and R. rubella, respectively, indicating possible gene transferring events. We further found frequent intron loss/gain and potential intron transfer events in Phallomycetidae mitogenomes during the evolution, and the mitogenomes of R. rubella contained a novel intron P44. Phylogenetic analyses using both Bayesian inference (BI) and Maximum Likelihood (ML) methods based on a combined mitochondrial gene dataset obtained an identical and well-supported phylogenetic tree for Basidiomycota, wherein R. cfr. rubripermanens and Turbinellus floccosus are sister species. This study served as the first report on mitogenomes from the genus Ramaria, which provides a basis for understanding the evolution, genetics, and taxonomy of this important fungal group.

Unravelling the Polytoxicology of Chlorfenapyr on Non-Target HepG2 Cells: The Involvement of Mitochondria-Mediated Programmed Cell Death and DNA Damage

Chlorfenapyr (CHL) is a type of insecticide with a wide range of insecticidal activities and unique targets. The extensive use of pesticides has caused an increase in potential risks to the environment and human health. However, the potential toxicity of CHL and its mechanisms of action on humans remain unclear. Therefore, human liver cells (HepG2) were used to investigate the cytotoxic effect and mechanism of toxicity of CHL at the cellular level. The results showed that CHL induced cellular toxicity in HepG2 cells and induced mitochondrial damage associated with reactive oxygen species (ROS) accumulation and mitochondrial calcium overload, ultimately leading to apoptosis and autophagy in HepG2 cells. Typical apoptotic changes occurred, including a decline in the mitochondrial membrane potential, the promotion of Bax/Bcl-2 expression causing the release of cyt-c into the cytosol, the activation of cas-9/-3, and the cleavage of PARP. The autophagic effects included the formation of autophagic vacuoles, accumulation of Beclin-1, transformation of LC3-II, and downregulation of p62. Additionally, DNA damage and cell cycle arrest were detected in CHL-treated cells. These results show that CHL induced cytotoxicity associated with mitochondria-mediated programmed cell death (PCD) and DNA damage in HepG2 cells.

Comparative Mitogenomic Analysis Reveals Intraspecific, Interspecific Variations and Genetic Diversity of Medical Fungus Ganoderma

Ganoderma species are widely distributed in the world with high diversity. Some species are considered to be pathogenic fungi while others are used as traditional medicine in Asia. In this study, we sequenced and assembled four Ganoderma complete mitogenomes, including G. subamboinense s118, G. lucidum s37, G. lingzhi s62, and G. lingzhi s74. The sizes of the four mitogenomes ranged from 50,603 to 73,416 bp. All Ganoderma specimens had a full set of core protein-coding genes (PCGs), and the rps3 gene of Ganoderma species was detected to be under positive or relaxed selection. We found that the non-conserved PCGs, which encode RNA polymerases, DNA polymerases, homing endonucleases, and unknown functional proteins, are dynamic within and between Ganoderma species. Introns were thought to be the main contributing factor in Ganoderma mitogenome size variation (p < 0.01). Frequent intron loss/gain events were detected within and between Ganoderma species. The mitogenome of G. lucidum s26 gained intron P637 in the cox3 gene compared with the other two G. lucidum mitogenomes. In addition, some rare introns in Ganoderma were detected in distinct Basidiomycetes, indicating potential gene transfer events. Comparative mitogenomic analysis revealed that gene arrangements also varied within and between Ganoderma mitogenomes. Using maximum likelihood and Bayesian inference methods with a combined mitochondrial gene dataset, phylogenetic analyses generated identical, well-supported tree topologies for 71 Agaricomycetes species. This study reveals intraspecific and interspecific variations of the Ganoderma mitogenomes, which promotes the understanding of the origin, evolution, and genetic diversity of Ganoderma species.

First two mitochondrial genomes for the order Filobasidiales reveal novel gene rearrangements and intron dynamics of Tremellomycetes

In the present study, two mitogenomes from the Filobasidium genus were assembled and compared with other Tremellomycetes mitogenomes. The mitogenomes of F. wieringae and F. globisporum both comprised circular DNA molecules, with sizes of 27,861 bp and 71,783 bp, respectively. Comparative mitogenomic analysis revealed that the genetic contents, tRNAs, and codon usages of the two Filobasidium species differed greatly. The sizes of the two Filobasidium mitogenomes varied greatly with the introns being the main factor contributing to mitogenome expansion in F. globisporum. Positive selection was observed in several protein-coding genes (PCGs) in the Agaricomycotina, Pucciniomycotina, and Ustilaginomycotina species, including cob, cox2, nad2, and rps3 genes. Frequent intron loss/gain events were detected to have occurred during the evolution of the Tremellomycetes mitogenomes, and the mitogenomes of 17 species from Agaricomycotina, Pucciniomycotina, and Ustilaginomycotina have undergone large-scale gene rearrangements. Phylogenetic analyses based on Bayesian inference and the maximum likelihood methods using a combined mitochondrial gene set generated identical and well-supported phylogenetic trees, wherein Filobasidium species had close relationships with Trichosporonales species. This study, which is the first report on mitogenomes from the order Filobasidiales, provides a basis for understanding the genomics, evolution, and taxonomy of this important fungal group.

Comparative mitochondrial genome analyses reveal conserved gene arrangement but massive expansion/contraction in two closely related Exserohilum pathogens

Exserohilum turcicum and E. rostratum, two closely related fungal species, are both economically important pathogens but have quite different target hosts (specific to plants and cross-kingdom infection, respectively). In the present study, complete circular mitochondrial genomes of the two Exserohilum species were sequenced and de novo assembled, which mainly comprised the same set of 13 core protein-coding genes (PCGs), two rRNAs, and a certain number of tRNAs and unidentified open reading frames (ORFs). Comparative analyses indicated that these two fungi had significant mitogenomic collinearity and consistent mitochondrial gene arrangement, yet with vastly different mitogenome sizes, 264,948 bp and 64,620 bp, respectively. By contrast with the 17 introns containing 17 intronic ORFs (one-to-one) in the E. rostratum mitogenome, E. turcicum involved far more introns (70) and intronic ORFs (126), which was considered as the main contributing factors of their mitogenome expansion/contraction. Within the generally intron-rich gene cox1, a total of 18 and 10 intron position classes (Pcls) were identified separately in the two mitogenomes. Moreover, 16.16% and 10.85% ratios of intra-mitogenomic repetitive regions were detected in E. turcicum and E. rostratum, respectively. Based on the combined mitochondrial gene dataset, we established a well-supported topology of phylogeny tree of 98 ascomycetes, implying that mitogenomes may act as an effective molecular marker for fungal phylogenetic reconstruction. Our results served as the first report on mitogenomes in the genus Exserohilum, and would have significant implications in understanding the origin, evolution and pathogenic mechanisms of this fungal lineage.

Comparative analysis of the complete mitochondrial genomes of four cordyceps fungi

Cordyceps is a large group of entomogenous, medicinally important fungi. In this study, we sequenced, assembled, and annotated the entire mitochondrial genome of Ophiocordyceps xuefengensis, in addition to comparing it against other three complete cordyceps mitogenomes that were previously published. Comparative analysis indicated that the four complete mitogenomes are all composed of circular DNA molecules, although their sizes significantly differ due to high variability in intron and intergenic region sizes in the Ophiocordyceps sinensis and O. xuefengensis mitogenomes. All mitogenomes contain 14 conserved genes and two ribosomal RNA genes, but varying numbers of tRNA introns. The Ka/Ks ratios for all 14 PCGs and rps3 were all less than 1, indicating that these genes have been subject to purifying selection. Phylogenetic analysis was conducted using concatenated amino acid and nucleotide sequences of the 14 PCGs and rps3 using two different methods (Maximum Likelihood and Bayesian analysis), revealing highly supported relationships between O. xuefengensis and other Ophiocordyceps species, in addition to a close relationship with O. sinensis. Further, the analyses indicated that cox1 and rps3 play important roles in population differentiation. These mitogenomes will allow further study of the population genetics, taxonomy, and evolutionary biology of medicinally important cordyceps species.

Novel mitochondrial gene rearrangements pattern in the millipede Polydesmus sp. GZCS-2019 and phylogenetic analysis of the Myriapoda

The subphylum Myriapoda included four extant classes (Chilopoda, Symphyla, Diplopoda, and Pauropoda). Due to the limitation of taxon sampling, the phylogenetic relationships within Myriapoda remained contentious, especially for Diplopoda. Herein, we determined the complete mitochondrial genome of Polydesmus sp. GZCS-2019 (Myriapoda: Polydesmida) and the mitochondrial genomes are circular molecules of 15,036 bp, with all genes encoded on + strand. The A+T content is 66.1%, making the chain asymmetric, and exhibits negative AT-skew (-0.236). Several genes rearrangements were detected and we propose a new rearrangement model: "TD (N\R) L + C" based on the genome-scale duplication + (non-random/random) loss + recombination. Phylogenetic analyses demonstrated that Chilopoda and Symphyla both were monophyletic group, whereas Pauropoda was embedded in Diplopoda to form the Dignatha. Divergence time showed the first split of Myriapoda occurred between the Chilopoda and other classes (Wenlock period of Silurian). We combine phylogenetic analysis, divergence time, and gene arrangement to yield valuable insights into the evolutionary history and classification relationship of Myriapoda and these results support a monophyletic Progoneata and the relationship (Chilopoda + (Symphyla + (Diplopoda + Pauropoda))) within myriapod. Our results help to better explain the gene rearrangement events of the invertebrate mitogenome and lay the foundation for further phylogenetic study of Myriapoda.

Characterization of the complete mitochondrial genome of Aspergillus terricola (Aspergillaceae, Eurotiales), isolated from soy sauce fermentation system

In the present study, the complete mitochondrial genome of Aspergillus terricola É.J. Marchal 1893 was sequenced and assembled. The mitochondrial genome of A. terricola was composed of circular DNA molecules, with a total size of 28,689 bp. The GC content of the A. terricola mitochondrial genome was 26.34%. A total of 18 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, and 26 transfer RNA (tRNA) genes were detected in the A. terricola mitochondrial genome. Phylogenetic analysis based on the combined mitochondrial gene dataset indicated that the A. terricola exhibited a close relationship with A. parasiticus.

Characterization of the complete mitochondrial genome of Dioszegia changbaiensis (Tremellales: Bulleribasidiaceae) with phylogenetic implications

In this study, the complete mitochondrial genome of Dioszegia changbaiensis we sequenced and assembled by the next-generation sequencing. The complete mitochondrial genome of Dioszegia changbaiensis contained 22 protein-coding genes (PCG), two ribosomal RNA (rRNA) genes, and 22 transfer RNA (tRNA) genes. The total length of the Dioszegia changbaiensis mitochondrial genome is 34,853 bp, and the GC content of the mitochondrial genome is 41.88%. Phylogenetic analysis based on a combined mitochondrial gene dataset indicated that the mitochondrial genome of Dioszegia changbaiensis exhibited a close relationship with that of Hannaella oryzae.

Characterization of the first complete chloroplast genome of Amaranthus hybridus (Caryophyllales: Amaranthaceae) with phylogenetic implications

In the present study, the complete chloroplast genome of Amaranthus hybridus was sequenced and assembled. The complete chloroplast genome of Amaranthus hybridus is 150,709 in size, with the GC content of 36.56%. The chloroplast genome of Amaranthus hybridus contained 86 protein-coding genes (PCGs), eight ribosomal RNA (rRNA) genes, and 37 transfer RNA (tRNA) genes. Phylogenetic analysis based on combined chloroplast gene dataset indicated that the Amaranthus hybridus exhibited a close relationship with A. hypochondriacus and A. caudatus.

The first complete mitochondrial genome of mushroom Leucoagaricus naucinus (Agaricaceae, Agaricales) and insights into its phylogeny

Leucoagaricus naucinus (Fr.) Singer is a mycorrhizal fungus widely distributed in the northern Hemisphere. In the present study, the complete mitochondrial genome of Leucoagaricus naucinus was sequenced, assembled, and annotated. The L. naucinus mitochondrial genome was composed of circular DNA molecules, with the total size of 61,434 bp. The GC content of the L. naucinus mitochondrial genome was 26.07%. A total of 30 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, and 26 transfer RNA (tRNA) genes were detected in the L. naucinus mitochondrial genome. Phylogenetic analysis based on combined mitochondrial gene dataset indicated that the L. naucinus exhibited a close relationship with Agaricus bisporus.

Induction of Apoptosis in HeLa Cells by a Novel Peptide from Fruiting Bodies of Morchella importuna via the Mitochondrial Apoptotic Pathway

Morels (Morchella spp.) are a genus of edible fungi with important economic and medicinal value. In this study, a novel peptide (MIPP) was extracted from the fruiting bodies of Morchella importuna using gel filtration chromatography. Structural analysis showed that the molecular mass of MIPP is 831 Da, and it has a simple amino acid sequence: Ser-Leu-Ser-Leu-Ser-Val-Ala-Arg. To explore the antitumor activity of MIPP, the effect of MIPP on HeLa cell apoptosis and the underlying preventative mechanisms were investigated. Results showed that MIPP reduced the viability of HeLa cells in a concentration-dependent manner. TUNEL analysis and flow cytometric examination showed that MIPP decreased cell proliferation via a mitochondrial-dependent pathway, as manifested by downregulation of Bcl-2/Bax, promotion of the movement of cytochrome C from the mitochondria to the cytoplasm, and triggering of caspase-9 and caspase-3. Therefore, MIPP may be a promising tumor-preventive agent, especially in human cervical cancer.

Characterization of the complete mitochondrial genome of Peniophora lycii (Russulales: Peniophoraceae) with its phylogenetic analysis

Peniophora lycii is a resupinate lichen-like species distributed all over the world. In the present study, we sequenced and assembled the complete mitochondrial genome of Peniophora lycii. The size of the mitochondrial genome of P. lycii was 38,296 bp, with a GC content of 25.89%. Twenty protein-coding genes, 2 ribosomal RNA genes, and 24 transfer RNA genes were identified in the mitochondrial genome of P. lycii. Phylogenetic analysis based on combined mitochondrial gene dataset indicated that the mitochondrial genome of P. lycii exhibited a close relationship with that of Heterobasidion irregulare.

The first complete mitochondrial genome of edible and medicinal fungus Chroogomphus rutilus (Gomphidiaceae, Boletales) and insights into its phylogeny

In the present study, we assembled and annotated the complete mitochondrial genome of Chroogomphus rutilus. The complete mitochondrial genome of C. rutilus was composed of circular DNA molecules, with a size of 37,508 bp. The GC content of the C. rutilus mitogenome was 22.82%. A total of 18 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, and 24 transfer RNA (tRNA) genes were detected in the C. rutilus mitogenome. Phylogenetic analysis based on combined mitochondrial gene dataset indicated that the C. rutilus exhibited a close relationship with species from the genus Rhizopogon. This study served as the first report on the complete mitochondrial genome from the family Gomphidiaceae, which will promote the understanding of phylogeny, evolution, and taxonomy of this important fungal species.

The first complete mitochondrial genome of Macalpinomyces bursus (Ustilaginales: Ustilaginaceae) and insights into its phylogeny

In the present study, the complete mitochondrial genome of Macalpinomyces bursus (Berk.) Vanky 2002 was sequenced and assembled. The complete mitochondrial genome of M. bursus was 49,024 bp in length, with the GC content of 30.4%. The M. bursus mitochondrial genome contained 27 protein-coding genes, 2 ribosomal RNA (rRNA) genes, and 22 transfer RNA (tRNA) genes. Phylogenetic analysis based on combined mitochondrial gene dataset indicated that the M. bursus exhibited a close relationship with species from the genera Ustilago, Sporisorium, and Anthracocystis.

The first complete chloroplast genome of Fagopyrum leptopodum (Diels) Hedberg (Caryophyllales: Polygonaceae) with phylogenetic implications

In the present study, we sequenced and assembled the complete chloroplast genome of Fagopyrum leptopodum (Diels) Hedberg. The chloroplast genome of F. leptopodum was composed of 85 protein-coding genes, 8 ribosomal RNA genes, and 37 transfer RNA genes. The F. leptopodum chloroplast genome is 159,375 bp in length, with a GC content of 37.81%. Phylogenetic analysis based on the combined chloroplast gene dataset indicated that the F. leptopodum exhibited a close relationship with Fagopyrum luojishanense.

Evolutionary Insights Into Two Widespread Ectomycorrhizal Fungi (Pisolithus) From Comparative Analysis of Mitochondrial Genomes

The genus Pisolithus is a group of global ectomycorrhizal fungi. The characterizations of Pisolithus mitochondrial genomes have still been unknown. In the present study, the complete mitogenomes of two Pisolithus species, Pisolithus microcarpus, and Pisolithus tinctorius, were assembled and compared with other Boletales mitogenomes. Both Pisolithus mitogenomes comprised circular DNA molecules with sizes of 43,990 and 44,054 bp, respectively. Comparative mitogenomic analysis showed that the rps3 gene differentiated greatly between Boletales species, and this gene may be subjected to strong pressure of positive selection between some Boletales species. Several plasmid-derived genes and genes with unknown functions were detected in the two Pisolithus mitogenomes, which needs further analysis. The two Pisolithus species show a high degree of collinearity, which may represent the gene arrangement of the ancestors of ectomycorrhizal Boletales species. Frequent intron loss/gain events were detected in Boletales and basidiomycetes, and intron P717 was only detected in P. tinctorius out of the eight Boletales mitogenomes tested. We reconstructed phylogeny of 79 basidiomycetes based on combined mitochondrial gene dataset, and obtained well-supported phylogenetic topologies. This study served as the first report on the mitogenomes of the family Pisolithaceae, which will promote the understanding of the evolution of Pisolithus species.

Characterization of the complete chloroplast genome of Hordeum vulgare L. var. trifurcatum with phylogenetic analysis

In the present study, the complete chloroplast genome of Hordeum vulgare L. var. trifurcatum was sequenced, assembled and compared with closely related species. The chloroplast genome of Hordeum vulgare L. var. trifurcatum was composed of 84 protein-coding genes (PCG), 8 ribosomal RNA (rRNA) genes, and 38 transfer RNA (tRNA) genes. The Hordeum vulgare L. var. trifurcatum chloroplast genome is 136,485 bp in size, with the GC content of 38.32%. Phylogenetic analysis based on the combined chloroplast gene dataset indicated that the Hordeum vulgare L. var. trifurcatum exhibited a close relationship with Hordeum vulgare subsp. spontaneum and Hordeum vulgare subsp. vulgare.

Characterization of the Complete Mitochondrial Genome of Basidiomycete Yeast Hannaella oryzae: Intron Evolution, Gene Rearrangement, and Its Phylogeny

In this study, the mitogenome of Hannaella oryzae was sequenced by next-generation sequencing (NGS) and successfully assembled. The H. oryzae mitogenome comprised circular DNA molecules with a total size of 26,444 bp. We found that the mitogenome of H. oryzae partially deleted the tRNA gene transferring cysteine. Comparative mitogenomic analyses showed that intronic regions were the main factors contributing to the size variations of mitogenomes in Tremellales. Introns of the cox1 gene in Tremellales species were found to have undergone intron loss/gain events, and introns of the H. oryzae cox1 gene may have different origins. Gene arrangement analysis revealed that H. oryzae contained a unique gene order different from other Tremellales species. Phylogenetic analysis based on a combined mitochondrial gene set resulted in identical and well-supported topologies, wherein H. oryzae was closely related to Tremella fuciformis. This study represents the first report of mitogenome for the Hannaella genus, which will allow further study of the population genetics, taxonomy, and evolutionary biology of this important phylloplane yeast and other related species.

Genome sequence and transcriptome profiles of pathogenic fungus Paecilomyces penicillatus reveal its interactions with edible fungus Morchella importuna

Paecilomyces penicillatus is one of the pathogens of morels, which greatly affects the yield and quality of Morchella spp.. In the present study, we de novo assembled the genome sequence of the fungus P. penicillatus SAAS_ppe1. We analyzed the transcriptional profile of P. penicillatus SAAS_ppe1 infection of Morchella importuna at different stages (3 days and 6 days after infection) and the response of M. importuna using the transcriptome. The assembled genome sequence of P. penicillatus SAAS_ppe1 was 39.78 Mb in length (11 scaffolds; scaffold N50, 6.50 Mb), in which 99.7% of the expected genes were detected. A total of 7.48% and 19.83% clean transcriptional reads from the infected sites were mapped to the P. penicillatus genome at the early and late stages of infection, respectively. There were 3,943 genes differently expressed in P. penicillatus at different stages of infection, of which 24 genes had increased expression with the infection and infection stage, including diphthamide biosynthesis, aldehyde reductase, and NAD (P)H-hydrate epimerase (P < 0.05). Several genes had variable expression trends at different stages of infection, indicating P. penicillatus had diverse regulation patterns to infect M. importuna. GO function, involving cellular components, and KEGG pathways, involving glycerolipid metabolism, and plant-pathogen interaction were significantly enriched during infection by P. penicillatus. The expression of ten genes in M. importuna increased during the infection and infection stage, and these may regulate the response of M. importuna to P. penicillatus infection. This is the first comprehensive study on P. penicillatus infection mechanism and M. importuna response mechanism, which will lay a foundation for understanding the fungus-fungus interactions, gene functions, and variety breeding of pathogenic and edible fungi.

Characterization and phylogenetic analysis of the complete mitochondrial genome of pathogen Trichosporon inkin (Trichosporonales: Trichosporonaceae)

In the present study, the complete mitochondrial genome of Trichosporon inkin was sequenced and assembled. The complete mitochondrial genome of T. inkin contained 22 protein-coding genes (PCG), 2 ribosomal RNA (rRNA) genes, and 24 transfer RNA (tRNA) genes. The total size of the T. inkin mitochondrial genome is 39,466 bp, with the GC content of 27.56%. Phylogenetic analysis based on combined mitochondrial gene dataset indicated that the T. inkin exhibited a close relationship with Trichosporon asahii.

Comparative Mitogenomic Analysis Reveals Dynamics of Intron Within and Between Tricholoma Species and Phylogeny of Basidiomycota

The genus of Tricholoma is a group of important ectomycorrhizal fungi. The overlapping of morphological characteristics often leads to the confusion of Tricholoma species classification. In this study, the mitogenomes of five Tricholoma species were sequenced based on the next-generation sequencing technology, including T. matsutake SCYJ1, T. bakamatsutake, T. terreum, T. flavovirens, and T. saponaceum. These five mitogenomes were all composed of circular DNA molecules, with sizes ranging from 49,480 to 103,090 bp. Intergenic sequences were considered to be the main factor contributing to size variations of Tricholoma mitogenomes. Comparative mitogenomic analysis showed that the introns of the Agaricales mitogenome experienced frequent loss/gain events. In addition, potential gene transfer was detected between the mitochondrial and nuclear genomes of the five species of Tricholoma. Evolutionary analysis showed that the rps3 gene of the Tricholoma species was under positive selection or relaxed selection in the evolutionary process. In addition, large-scale gene rearrangements were detected between some Tricholoma species. Phylogenetic analysis using the Bayesian inference and maximum likelihood methods based on a combined mitochondrial gene set yielded identical and well-supported tree topologies. This study promoted the understanding of the genetics, evolution, and phylogeny of the Tricholoma genus and related species.

A High-Efficiency Artificial Synthetic Pathway for 5-Aminovalerate Production From Biobased L-Lysine in Escherichia coli

Bioproduction of 5-aminovalerate (5AVA) from renewable feedstock can support a sustainable biorefinery process to produce bioplastics, such as nylon 5 and nylon 56. In order to achieve the biobased production of 5AVA, a 2-keto-6-aminocaproate-mediated synthetic pathway was established. Combination of L-Lysine α-oxidase from Scomber japonicus, α-ketoacid decarboxylase from Lactococcus lactis and aldehyde dehydrogenase from Escherichia coli could achieve the biosynthesis of 5AVA from biobased L-Lysine in E. coli. The H₂O₂ produced by L-Lysine α-oxidase was decomposed by the expression of catalase KatE. Finally, 52.24 g/L of 5AVA were obtained through fed-batch biotransformation. Moreover, homology modeling, molecular docking and molecular dynamic simulation analyses were used to identify mutation sites and propose a possible trait-improvement strategy: the expanded catalytic channel of mutant and more hydrogen bonds formed might be beneficial for the substrates stretch. In summary, we have developed a promising artificial pathway for efficient 5AVA synthesis.

Panorama of intron dynamics and gene rearrangements in the phylum Basidiomycota as revealed by the complete mitochondrial genome of Turbinellus floccosus

In the present study, the complete mitogenome of Turbinellus floccosus was sequenced, assembled, and compared with other basidiomycete mitogenomes. The mitogenome of T. floccosus consists of a circular DNA molecule, with a size of 62,846 bp. Gene arrangement analysis indicated that large-scale gene rearrangements occurred in the levels of family and genus of basidiomycete species, and the mitogenome of T. floccosus contained a unique gene order. A significant correlation between the number of introns and the mitochondrial genome size of Basidiomycota were detected (P < 0.01). A total of 896 introns were detected in the core protein-coding genes (PCGs) of 74 basidiomycete species, and the cox1 gene was the largest host gene of basidiomycete introns. Intron position class (Pcls) P383 in the cox1 gene was the most common intron in Basidiomycota, which distributed in 40 of 74 basidiomycete species. In addition, frequent intron loss/gain events were detected in basidiomycete species. More than 50% of bases around insertion sites (- 15 bp to 15 bp) of Pcls from different species were conservative, indicating site preferences of intron insertions in Basidiomycota. Further analysis showed that 76.09% of introns tended to insert downstream to a T base in Basidiomycota. Phylogenetic analysis for 74 basidiomycetes indicated mitochondrial genes are effective molecular markers for phylogeny of basidiomycetes. The study served as the first report on the mitogenome from the family Gomphaceae, which will help to understand the intron origin and evolution in Basidiomycota. KEY POINTS: • The mitogenome of Turbinellus floccosus had a unique gene arrangement. • Intron loss/gain events were detected in the 74 basidiomycete species. • Introns tend to insert downstream of a T base in basidiomycete mitogenomes.

Comparative mitochondrial genome analysis reveals intron dynamics and gene rearrangements in two Trametes species

Trametes species are efficient wood decomposers that are widespread throughout the world. Mitogenomes have been widely used to understand the phylogeny and evolution of fungi. Up to now, two mitogenomes from the Trametes genus have been revealed. In the present study, the complete mitogenomes of two novel Trametes species, Trametes versicolor and T. coccinea, were assembled and compared with other Polyporales mitogenomes. Both species contained circular DNA molecules, with sizes of 67,318 bp and 99,976 bp, respectively. Comparative mitogenomic analysis indicated that the gene number, length and base composition varied between the four Trametes mitogenomes we tested. In addition, all of the core protein coding genes in Trametes species were identified and subjected to purifying selection. The mitogenome of T. coccinea contained the largest number of introns among the four Trametes species tested, and introns were considered the main factors contributing to size variations of Polyporales. Several novel introns were detected in the Trametes species we assembled, and introns identified in Polyporales were found to undergo frequent loss/gain events. Large-scale gene rearrangements were detected between closely related Trametes species, including gene inversions, insertions, and migrations. A well-supported phylogenetic tree for 77 Basidiomycetes was obtained based on the combined mitochondrial gene set using 2 phylogenetic inference methods. The results showed that mitochondrial genes are effective molecular markers for understanding the phylogeny of Basidiomycetes. This study is the first to report the mitogenome rearrangement and intron dynamics of Trametes species, which shed light on the evolution of Trametes and other related species.

The first eleven mitochondrial genomes from the ectomycorrhizal fungal genus (Boletus) reveal intron loss and gene rearrangement

In the present study, eleven novel complete mitogenomes of Boletus were assembled and compared. The eleven complete mitogenomes were all composed of circular DNA molecules, with sizes ranging from 32,883 bp to 48,298 bp. The mitochondrial gene arrangement of Boletus varied greatly from other Boletales mitogenomes, and gene position reversal were observed frequently in the evolution of Boletus. Across the 15 core protein-coding genes (PCGs) tested, atp9 had the least and rps3 had the largest genetic distances among the eleven Boletus species, indicating varied evolution rates of core PCGs. In addition, the Ka/Ks value for nad3 gene was >1, suggesting that this gene was subject to possible positive selection pressure. Comparative mitogenomic analysis indicated that the intronic region was significantly correlated with the size of mitogenomes in Boletales. Two large-scale intron loss events were detected in the evolution of Boletus. Phylogenetic analyses based on a combined mitochondrial gene dataset yielded a well-supported (BPP ≥ 0.99; BS =100) phylogenetic tree for 72 Agaricomycetes, and the Boletus species had a close relationship with Paxillus. This study served as the first report on complete mitogenomes in Boletus, which will further promote investigations of the genetics, evolution and phylogeny of the Boletus genus.

The mitogenomes of two saprophytic Boletales species (Coniophora) reveals intron dynamics and accumulation of plasmid-derived and non-conserved genes

The order Boletales is a group of fungi with complex life styles, which include saprophytic and ectomycorrhizal mushroom-forming fungi. In the present study, the complete mitogenomes of two saprophytic Boletales species, Coniophora olivacea, and C. puteana, were assembled and compared with mitogenomes of ectomycorrhizal Boletales. Both mitogenomes comprised circular DNA molecules with sizes of 78,350 bp and 79,655 bp, respectively. Comparative mitogenomic analysis indicated that the two saprophytic Boletales species contained more plasmid-derived (7 on average) and unknown functional genes (12 on average) than the four ectomycorrhizal Boletales species previously reported. In addition, the core protein coding genes, nad2 and rps3, were found to be subjected to positive selection pressure between some Boletales species. Frequent intron gain/loss events were detected in Boletales and Basidiomycetes, and several novel intron classes were found in two Coniophora species. A total of 33 introns were detected in C. olivacea, and most were found to have undergone contraction in the C. olivacea mitogenome. Mitochondrial genes of Coniophora species were found to have undergone large-scale gene rearrangements, and the accumulation of intra-genomic repeats in the mitogenome was considered as one of the main contributing factors. Based on combined mitochondrial gene sets, we obtained a well-supported phylogenetic tree for 76 Basidiomycetes, demonstrating the utility of mitochondrial gene analysis for inferring Basidiomycetes phylogeny. The study served as the first report on the mitogenomes of the family Coniophorineae, which will help to understand the origin and evolution patterns of Boletales species with complex lifestyles.

The 287,403 bp Mitochondrial Genome of Ectomycorrhizal Fungus Tuber calosporum Reveals Intron Expansion, tRNA Loss, and Gene Rearrangement

In the present study, the mitogenome of Tuber calosporum was assembled and analyzed. The mitogenome of T. calosporum comprises 15 conserved protein-coding genes, two rRNA genes, and 14 tRNAs, with a total size of 287,403 bp. Fifty-eight introns with 170 intronic open reading frames were detected in the T. calosporum mitogenome. The intronic region occupied 69.41% of the T. calosporum mitogenome, which contributed to the T. calosporum mitogenome significantly expand relative to most fungal species. Comparative mitogenomic analysis revealed large-scale gene rearrangements occurred in the mitogenome of T. calosporum, involving gene relocations and position exchanges. The mitogenome of T. calosporum was found to have lost several tRNA genes encoding for cysteine, aspartate, histidine, etc. In addition, a pair of fragments with a total length of 32.91 kb in both the nuclear and mitochondrial genomes of T. calosporum was detected, indicating possible gene transfer events. A total of 12.83% intragenomic duplications were detected in the T. calosporum mitogenome. Phylogenetic analysis based on mitochondrial gene datasets obtained well-supported tree topologies, indicating that mitochondrial genes could be reliable molecular markers for phylogenetic analyses of Ascomycota. This study served as the first report on mitogenome in the family Tuberaceae, thereby laying the groundwork for our understanding of the evolution, phylogeny, and population genetics of these important ectomycorrhizal fungi.

Mitochondrial evolution in the entomopathogenic fungal genus Beauveria

Species in the fungal genus Beauveria are pathogens of invertebrates and have been commonly used as the active agent in biopesticides. After many decades with few species described, recent molecular approaches to classification have led to over 25 species now delimited. Little attention has been given to the mitochondrial genomes of Beauveria but better understanding may led to insights into the nature of species and evolution in this important genus. In this study, we sequenced the mitochondrial genomes of four new strains belonging to Beauveria bassiana, Beauveria caledonica and Beauveria malawiensis, and compared them to existing mitochondrial sequences of related fungi. The mitochondrial genomes of Beauveria ranged widely from 28,806 to 44,135 base pairs, with intron insertions accounting for most size variation and up to 39% (B. malawiensis) of the mitochondrial length due to introns in genes. Gene order of the common mitochondrial genes did not vary among the Beauveria sequences, but variation was observed in the number of transfer ribonucleic acid genes. Although phylogenetic analysis using whole mitochondrial genomes showed, unsurprisingly, that B. bassiana isolates were the most closely related to each other, mitochondrial codon usage suggested that some B. bassiana isolates were more similar to B. malawiensis and B. caledonica than the other B. bassiana isolates analyzed.

Mitogenomes of Two Phallus Mushroom Species Reveal Gene Rearrangement, Intron Dynamics, and Basidiomycete Phylogeny

Phallus indusiatus and Phallus echinovolvatus are edible bamboo mushrooms with pharmacological properties. We sequenced, assembled, annotated, and compared the mitogenomes of these species. Both mitogenomes were composed of circular DNA molecules, with sizes of 89,139 and 50,098 bp, respectively. Introns were the most important factor in mitogenome size variation within the genus Phallus. Phallus indusiatus, P. echinovolvatus, and Turbinellus floccosus in the subclass Phallomycetidae have conservative gene arrangements. Large-scale gene rearrangements were observed in species representing 42 different genera of Basidiomycetes. A variety of intron position classes were found in the 44 Basidiomycete species analyzed. A novel group II intron from the P. indusiatus mitogenome was compared with other fungus species containing the same intron, and we demonstrated that the insertion sites of the intron had a base preference. Phylogenetic analyses based on combined gene datasets yielded well-supported Bayesian posterior probability (BPP = 1) topologies. This indicated that mitochondrial genes are reliable molecular markers for analyzing the phylogenetic relationships of the Basidiomycetes. This is the first study of the mitogenome of the genus Phallus, and it increases our understanding of the population genetics and evolution of bamboo mushrooms and related species.

The 256 kb mitochondrial genome of Clavaria fumosa is the largest among phylum Basidiomycota and is rich in introns and intronic ORFs

In the present study, the complete mitogenome of Clavaria fumosa, was sequenced, assembled, and compared. The complete mitogenome of C. fumosa is 256,807 bp in length and is the largest mitogenomes among all Basidiomycota mitogenomes reported. Comparative mitogenomic analysis indicated that the C. fumosa mitogenome contained the most introns and intronic ORFs among all fungal mitogenomes. Large intergenic regions, intronic regions, accumulation of repeat sequences and plasmid-derived genes together promoted the size expansion of the C. fumosa mitogenome. In addition, the rps3 gene was found subjected to positive selection between some Agaricales species. We found frequent intron gain/loss events in Agaricales mitogenomes, and four novel intron classes were detected in the C. fumosa mitogenome. Large-scale gene rearrangements were found occurred in Agaricales species and the C. fumosa mitogenome had a unique gene arrangement which differed from other Agaricales species. Phylogenetic analysis for 76 Basidiomycetes based on combined mitochondrial gene sets indicated that mitochondrial genes could be used as effective molecular markers for reconstructing evolution of Basidiomycota. The study served as the first report on the mitogenomes of the family Clavariaceae, which will promote the understanding of the genetics, evolution and taxonomy of C. fumosa and related species.

The complete mitochondrial genome of medicinal fungus Taiwanofungus camphoratus reveals gene rearrangements and intron dynamics of Polyporales

Taiwanofungus camphoratus is a highly valued medicinal mushroom that is endemic to Taiwan, China. In the present study, the mitogenome of T. camphoratus was assembled and compared with other published Polyporales mitogenomes. The T. camphoratus mitogenome was composed of circular DNA molecules, with a total size of 114,922 bp. Genome collinearity analysis revealed large-scale gene rearrangements between the mitogenomes of Polyporales, and T. camphoratus contained a unique gene order. The number and classes of introns were highly variable in 12 Polyporales species we examined, which proved that numerous intron loss or gain events occurred in the evolution of Polyporales. The Ka/Ks values for most core protein coding genes in Polyporales species were less than 1, indicating that these genes were subject to purifying selection. However, the rps3 gene was found under positive or relaxed selection between some Polyporales species. Phylogenetic analysis based on the combined mitochondrial gene set obtained a well-supported topology, and T. camphoratus was identified as a sister species to Laetiporus sulphureus. This study served as the first report on the mitogenome in the Taiwanofungus genus, which will provide a basis for understanding the phylogeny and evolution of this important fungus.

Characterization of the complete mitochondrial genome of Sterigmatomyces hyphaenes (Agaricostilbales: Agaricostilbaceae) and implications for its phylogeny

In this study, the complete mitochondrial genome of Sterigmatomyces hyphaenes was sequenced by the next-generation sequencing. The complete mitochondrial genome of S. hyphaenes contained 17 protein-coding genes (PCG), 2 ribosomal RNA (rRNA) genes, and 23 transfer RNA (tRNA) genes. The total size of the S. hyphaenes mitochondrial genome is 26,198 bp, and the GC content of the mitochondrial genome is 42.08%. Phylogenetic analysis based on the combined mitochondrial gene dataset indicated that the mitochondrial genome of S. hyphaenes exhibited a close relationship with that of Rhodotorula mucilaginosa.

The First Mitochondrial Genome for Geastrales (Sphaerobolus stellatus) Reveals Intron Dynamics and Large-Scale Gene Rearrangements of Basidiomycota

In this study, the mitogenome of artillery fungus, Sphaerobolus stellatus, was assembled and compared with other Basidiomycota mitogenomes. The Sphaerobolus stellatus mitogenome was composed of circular DNA molecules, with a total size of 152,722 bp. Accumulation of intergenic and intronic sequences contributed to the Sphaerobolus stellatus mitogenome becoming the fourth largest mitogenome among Basidiomycota. We detected large-scale gene rearrangements in Basidiomycota mitogenomes, and the Sphaerobolus stellatus mitogenome contains a unique gene order. The quantity and position classes of intron varied between 75 Basidiomycota species we tested, indicating frequent intron loss/gain events occurred in the evolution of Basidiomycota. A novel intron position classes (P1281) was detected in the Sphaerobolus stellatus mitogenome, without any homologous introns from other Basidiomycota species. A pair of fragments with a total length of 9.12 kb in both the nuclear and mitochondrial genomes of Sphaerobolus stellatus was detected, indicating possible gene transferring events. Phylogenetic analysis based on the combined mitochondrial gene set obtained well-supported tree topologies (Bayesian posterior probabilities ≥ 0.99; bootstrap values ≥98). This study served as the first report on the mitogenome from the order Geastrales, which will promote the understanding of the phylogeny, population genetics, and evolution of the artillery fungus, Sphaerobolus stellatus.

Characterization of the complete mitochondrial genome of biocontrol yeast Sporobolomyces sp. (Sporidiobolales: Sporidiobolaceae) with phylogenetic analysis

In this study, we obtained the complete mitochondrial genome of Sporobolomyces sp. using next-generation sequencing. The complete mitochondrial genome of Sporobolomyces sp. contained 15 protein-coding genes (PCG), two ribosomal RNA (rRNA) genes, and 25 transfer RNA (tRNA) genes. The total length of the Sporobolomyces sp. mitochondrial genome is 26,430 bp, and the GC content of the mitochondrial genome is 39.32%. Phylogenetic analysis based on combined mitochondrial gene dataset indicated that the mitochondrial genome of Sporobolomyces sp. exhibited a close relationship with that of Rhodotorula mucilaginosa.