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.

The mitogenomes characterization of two Peltigera species (Peltigera elisabethae and Peltigera polydactylon) and comparative mitogenomic analyses of six Peltigera.

In the present study, the mitochondrial genomes of Peltigera elisabethae and P. polydactylon were sequenced and assembled. The two mitogenomes were composed of circular DNA molecules, with sizes of 64,034 bp and 59,208 bp, respectively. Comparative analysis showed that the genome size, GC content, GC skew, and AT skew varied between the two mitochondrial genomes. In codon analysis, phenylalanine (Phe), isoleucine (Ile), and leucine (Leu) were most frequently used in six Peltigera genomes. Evolutionary analysis showed that all 14 protein-coding genes (PCGs) were subject to purifying selection in the six Peltigera species. Regarding gene rearrangement, the PCGs of Peltigera had the same gene sequence and gene content, and a few intron sequences and spacer sequences were rearranged in Peltigera. In the phylogenetic analysis, we used Bayesian and ML methods to construct a phylogenetic tree. Two phylogenetic trees with consistent topology with high support indicate that mitochondrial genes were reliable molecular markers for analyzing the phylogenetic relationships. The present study enriches the mitochondrial genome data of Peltigera and promotes further understanding of the genetics and evolution of the Peltigera genus.

Comparative analysis of metabolic mechanisms in the remediation of Cd-polluted alkaline soil in cotton field by biochar and biofertilizer.

To screen environmentally friendly and efficient Cd pollution remediation material, the effects of BC and BF on soil Cd bio-availability and cotton Cd absorption were analyzed under Cd exposure. Besides, the differences in metabolic mechanisms by which biochar (BC) and biofertilizer (BF) affect Cd-contaminated soil and cotton were also analyzed. The results showed that the application of BC and BF increased cotton dry matter accumulation, boll number, and single boll weight, and reduced the Cd content in cotton roots, stems, leaves, and bolls. At harvest, the Cd content in cotton roots in the BC and BF groups reduced by 15.23% and 16.33%, respectively, compared with that in the control. This was attributed to the conversion of carbonate-bound Cd (carbon-Cd) and exchangeable Cd (EX-Cd) by BC and BF into residual Cd (Res-Cd). It should be noted that the soil available Cd (Ava-Cd) content in the BF group was lower than that in the BC group. The metabolomic analysis results showed that for BC vs BF, the relative abundance of differential metabolites Caffeic acid, Xanthurenic acid, and Shikimic acid in soil and cotton roots were up-regulated. Mantel test found that cotton root exudate l-Histinine was correlated with the enrichment of Cd in various organs of cotton. Therefore, the application of BC and BF can alleviate Cd stress by reducing soil Ava-Cd content and cotton's Cd uptake, and BF is superior to BC in reducing Cd content in soil and cotton organs. This study will provide a reference for the development of efficient techniques for the remediation of Cd-polluted alkaline soil, and provide a basis for subsequent metagenomics analysis.

De novo mitochondrial genome sequencing of Cladonia subulata and phylogenetic analysis with other dissimilar species.

In this study, the complete mitochondrial genome of Cladonia subulata (L.) FH Wigg was sequenced and assembled and then compared with those of other Cladonia species. The mitogenome of Cladonia subulata, the type species of Cladonia, consisted of a circular DNA molecule of 58,895 bp 44 genes (15 protein-coding genes, 2 rRNA genes, and 27 tRNA genes). The base composition had shown an obvious AT preference, and all 27 tRNA genes formed a typical clover structure. Comparison with other 7 Cladonia species indicated that the duplication/loss of tRNAs had occurred during evolution, and introns appeared to explain the variation in cox1 genes in Cladonia, the mitochondrial genome tends to be generally conservative and local dynamic changes. Repeat sequences were mainly located in gene intervals, which were mainly distributed among intergenic spacers and may cause rearrangement of the mitogenome. The phylogenetic results showed that Cladonia subulata and C. polycarpoides were assigned to the Cladonia Subclade. The results add to the available mitochondrial genome sequence information of Cladonia subulata, provide basic data for the systematic development, resource protection, and genetic diversity research in Cladonia subulata, and also provide theoretical support for further genomic research of lichens.

The Chloroplast Genome of the Lichen Photobiont Trebouxiophyceae sp. DW1 and Its Phylogenetic Implications.

Lichens are symbiotic associations of algae and fungi. The genetic mechanism of the symbiosis of lichens and the influence of symbiosis on the size and composition of the genomes of symbiotic algae have always been intriguing scientific questions explored by lichenologists. However, there were limited data on lichen genomes. Therefore, we isolated and purified a lichen symbiotic alga to obtain a single strain (Trebouxiophyceae sp. DW1), and then obtained its chloroplast genome information by next-generation sequencing (NGS). The chloroplast genome is 129,447 bp in length, and the GC content is 35.2%. Repetitive sequences with the length of 30-35 bp account for 1.27% of the total chloroplast genome. The simple sequence repeats are all mononucleotide repeats. Codon usage analysis showed that the genome tended to use codon ending in A/U. By comparing the length of different regions of Trebouxiophyceae genomes, we found that the changes in the length of exons, introns, and intergenic sequences affect the size of genomes. Trebouxiophyceae had an unstable chloroplast genome structure, with IRs repeatedly losing during evolution. Phylogenetic analysis showed that Trebouxiophyceae is paraphyletic, and Trebouxiophyceae sp. DW1 is sister to the clade of Koliella longiseta and Pabia signiensis.

Mitochondrial genome from the lichenized fungus Peltigera rufescens (Weiss) Humb, 1793 (Ascomycota: Peltigeraceae).

Known colloquially as 'dog-lichens' or 'pelt-lichens', most species of Peltigera grow on soil and mosses. Some species contribute a significant amount of nitrogen to the environment and have been used as traditional medicines. We analyzed the complete mitochondrial genome of P. rufescens, which is a circular genome 65,199 bp in size and its CG content is 26.7%. It contains 15 protein-coding genes (PCGs), 27 transport RNAs (tRNAs), and 3 ribosomal RNAs (rRNAs). Also, the atp9 gene is present in the genome. We used the complete mitochondrial genome to construct a phylogenetic tree by the Bayesian method, which was consistent with the phylogenetic relationship published for P. membranacea which is closely related to P. rufescens.

The first complete chloroplast genome of Coptis chinensis var. brevisepala, with implication for the phylogeny of Ranunculaceae.

Coptis is one of the most important medicinal plant genera in eastern Asia. To better understand the evolution of this genus, the complete chloroplast genome of C. chinensis var. brevisepala was obtained by next-generation sequencing. The plastome of C. chinensis var. brevisepala is 155,426 bp in length, and consists of large (LSC, 84,488 bp) and small (SSC, 17,402bp) single-copy regions, separated by pair of inverted repeat regions (IRs, 26,768 bp). It harbours 111 unique genes, including 78 protein-coding genes, 29 transfer RNA genes, and four ribosomal RNA genes. Rps19 and ycf1 were pseudogenized due to incomplete duplication in IR regions. The nucleotide composition is asymmetric (30.5% A, 19.4% C, 18.7% G, and 31.3% T) with an overall G + C content of 38.2%. The phylogeny of Ranunculaceae based on 75 CDSs of 27 taxa showed that Ranunculoideae is paraphyletic and thus needs redefinition.

Characterization of the complete chloroplast genome of Lycium ruthenicum (Solanaceae).

Lycium ruthenicum is a precious desert plant with high medicinal and ecological values. It contains rich anthocyanins, which are safe natural pigments and could be used for natural food colorants. In this study, the complete chloroplast (cp) genome of L. ruthenicum was assembled on the basis of next generation sequencing. The whole genome is 154,996 bp in length, including two single copy regions (LSC: 85,993 bp and SSC: 18,213 bp) and two inverted repeat regions (IR: 25,395 bp). The overall G + C content of the genome is 37.9%. The cp genome consists of 111 unique genes, including 30 tRNA genes, 4 rRNA genes and 77 protein-coding genes. Phylogenetic analysis indicates that L. ruthenicum is closely clustered with Atropa belladonna, Przewalskia tangutica, and Scopolia parviflora.