tRNA Genes Research Articles

The complete mitochondrial genome of the shield-faced leaf-nosed bat from Yunnan Province in China

In this study, we sequenced the complete mitochondrial genome of the shield-faced leaf-nosed bat (Hipposideros lylei Thomas, 1914) using the Illumina platform. The mitochondrial genome of H. lylei is 16,856 bp in length, encoding 37 genes, which include 13 protein-coding genes, 22 tRNA genes, two rRNA genes, one replication start, and one non-coding control region (D-loop) of 417 bp in length. It has a G + C content of 42.0%, lower than the A + T content, indicating an obvious AT base preference. Phylogenetic analyses revealed that H. lylei clusters with three species of the genus Hipposideros in one branch and is relatively closely related to H. armiger and H. larvatus.

The complete chloroplast genome of Blechnopsis orientalis (Linnaeus) C. Presl 1753 (Blechnaceae)

Blechnopsis orientalis (Linnaeus) C. Presl (1753) is a fern used both as food and medicine. It is found primarily in southern China and Southeast Asia, thriving in warm, humid shrublands or sparse forest. The total length of the chloroplast genome is 155,211 bp, including a large single-copy region (LSC, 81,877 bp), a small single-copy region (SSC, 21,500 bp), and two inverted repeat regions (IRs, 25,917 bp). The GC content is 41.3%. A total of 131 genes were annotated, including 88 protein-coding genes, eight rRNA genes, and 35 tRNA genes. The phylogenetic analysis using the maximum-likelihood method showed that B. orientalis and Oceaniopteris gibba were closely related. This study provides genomic resources for phylogenetic genetics and resource exploitation of B. orientalis.

The complete mitochondrial genome of Heptathela kimurai (Araneae: Heptathelidae)

Heptathela kimurai (Kishida, 1920) is a spider that belongs to the family Heptathelidae which is a basial lineage of spiders. The molecular information of ancestral species belonging to families like Heptathelidae is comparatively limited when compared to spider species from derived families. Here we present the complete mitochondrial genome sequence (mtDNA) of H. kimurai. The sequence was obtained using massively parallel sequencing technology. The circular genome was 14,224 bp in length, and the AT content was 69.53%. The H. kimurai mitochondrial genome contains 13 protein-coding genes (PCGs), 21 tRNA genes, and 2 rRNA genes. The majority of PCGs were found in the heavy strand.

The mitochondrial genome of Huananpotamon koatenense (Rathbun, 1904) (Brachyura, Potamidae) and phylogenetic analysis

Freshwater crabs play essential roles in the well-functioning of the inland aquatic ecosystems. However, due to the lack of sufficient molecular resources, the study of freshwater crabs has been greatly hindered. In this study, the mitochondrial genome of Huananpotamon koatenense, a freshwater crab endemic to China, was sequenced for the first time. This mitogenome sequence is 15,528 bp long, and contains 13 protein-coding genes, 2 rRNA genes and 22 tRNA genes. Phylogenetic analyses based on 25 mitogenomes showed that H. koatenense was clustered with the known congeneric species of H. lichuanense.

Complete plastome sequence of Narcissus pseudonarcissus L., one of the most iconic European plants

Narcissus pseudonarcissus L. is one of the most iconic plants of the European flora. It is a species of great horticultural interest, but also an endangered and protected plant in the wild as a consequence of loss of natural habitats. Complete plastid genome was assembled from next-generation sequencing data obtaining a circular genome of 160,008 bp long assembly. It comprises a pair of inverted repeat regions, a large single-copy region (108,400 bp), and a small single-copy region (16,434 bp). It encodes 131 genes, including 87 protein coding genes, 37 tRNA genes and seven rRNA genes. Phylogeny showed the strict relationship between N. pseudonarcissus and Narcissus poeticus L. The complete plastome will provide a useful genetic resource for future conservation programmes, phylogenetic studies and horticultural applications.

The complete plastome of Thalictrum elegans Wall. ex Royle and its phylogenetic analysis

Thalictrum elegans Wall. ex Royle, a species within the family Ranunculaceae, is mainly distributed along forest margins and grassy slopes at altitudes 2700-4000 m on the Qinghai-Tibetan Plateau. Despite its wide distribution in alpine ecosystems, its genetic diversity remains poorly understood. In this study, we assembled and characterized the complete chloroplast genome of T. elegans, addressing a significant gap in our understanding of its genetic composition. The chloroplast genome is 155,864 base pairs long and contains 131 genes, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Phylogenetic analysis of 15 representative Thalictrum species revealed that the genus can be classified into three clades. T. elegans along with another nine other species formed the largest monophyletic clade and is most closely related to T. petaloideum and T. foliosum. These findings enhance our understanding of the genetic diversity of T. elegans and contribute to its conservation and utilization.

The complete chloroplast genome of Typha angustifolia and its phylogenetic position in Typhaceae

Typha angustifolia, commonly known as narrowleaf cattail, is a marginal, semi-aquatic, herbaceous perennial species with both ecological and edible values. In this study, the complete chloroplast (cp) genome of T. angustifolia was assembled using the next-generation sequencing technology. The whole cp genome was 161,597 bp in length, consisting of a large single copy (LSC, 89,119 bp) and a small single copy (SSC, 18,550 bp) separated by two copies of inverted region (IR, 26,964 bp). The genome encoded 113 unique genes, including 79 protein-coding genes, 30 tRNA genes, four rRNA genes, with 19 duplicated genes in the IR regions. Phylogenetic analysis showed that T. angustifolia is sister to Typha orientalis in the family Typhaceae. The cp genome of T. angustifolia is reported for the first time, which will provide essential and important genetic resources for future phylogenetic investigation within the genus Typha.

The complete chloroplast genome of rhododendron williamsianum (ericaceae)

Rhododendron williamsianum Rehder & E. H. Wilson 1913, is a plant with important horticultural value. Here we report its chloroplast genome. The total length of the chloroplast genome was 205,424 bp, with a GC content of 35.8%. It consisted of a 107,968 bp large single copy, a 2606 bp small single copy, and a pair of 47,425 bp inverted repeats separating them. Within the chloroplast genome, there were a total of 110 unique genes, which included 76 protein-coding genes, 4 rRNA genes, and 30 tRNA genes. Our phylogenetic analyses indicated that R. williamsianum was closely genetically related to R. sutchuenense and R. jingangshanicum. The findings from this study not only contribute to the genetic database of Rhododendron plants but also have implications for evolutionary research within the family Ericaceae.

Use of tRNA gene barriers improves stability of transgene expression in CHO cells.

Instability of transgene expression is a major challenge for the biopharmaceutical industry, which can impact yields and regulatory approval. Some tRNA genes (tDNAs) can resist epigenetic silencing, the principal mechanism of expression instability, and protect adjacent genes against the spread of repressive heterochromatin. We have taken two naturally occurring clusters of human tDNAs and tested their ability to reduce epigenetic silencing of transgenes integrated into the genome of Chinese hamster ovary (CHO) cells. We find sustained improvements in productivity both in adherent CHO-K1 cells and in an industrially relevant CHO-DG44 expression system (Apollo X, FUJIFILM Diosynth Biotechnologies). We conclude that specific tDNA clusters offer potential to mitigate the widespread problem of production instability.

Gilvirhabdus luticola gen. nov., sp. nov., a mesophilic and halophilic bacterium isolated from tidal flat sediment.

Two novel bacteria, MJ-SS3T and MJ-SS4, were isolated from tidal flat sediment sampled in Gochang, Republic of Korea. The isolates were Gram-stain-negative, aerobic, non-motile, rod-shaped, yellow-coloured, oxidase-positive, and catalase-positive. Strains MJ-SS3T and MJ-SS4 grew at 20-37 °C (optimum, 30 °C), at pH 6-8 (optimum, pH 7.0) and in the presence of 0-7 % (w/v) NaCl (optimum, 2.0 % NaCl). Strains MJ-SS3T and MJ-SS4 showed 99.9 % 16S rRNA gene sequence similarity. Phylogenetic analysis based on genome and 16S rRNA gene sequences indicated that strains MJ-SS3T and MJ-SS4 were affiliated with the family Flavobacteriaceae and most closely related to Formosa maritima 1494T (95.3 %), Hanstruepera flava NBU2984T (95.2 %), Yeosuana marina JLT21T (95.2 %), Meridianimaribacter flavus NH57NT (95.1 %), and Geojedonia litorea YCS-16T (95.1 %). The major respiratory quinone was menaquinone-6. The major identified polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, and amino lipids. The major cellular fatty acids of strain MJ-SS3T were iso-C15 : 1 G (24.6 %), iso-C15 : 0 (21.6 %), and iso-C17 : 0 3-OH (15.8 %). The genome length of strain MJ-SS3T is 3.1 Mbp (DNA G+C content, 32.5 mol%) and it has 2822 coding and 59 tRNA genes. The average amino acid identity and average nucleotide identity values, as well as biochemical, phylogenetic, and physiological characteristics, strongly supported the genotypic and phenotypic differentiation of strains MJ-SS3T and MJ-SS4 from other members of the family Flavobacteriaceae. Hence, strains MJ-SS3T and MJ-SS4 are considered to represent a novel species of a new genus in the family Flavobacteriaceae, for which the Gilvirhabdus luticola gen. nov., sp. nov. is proposed. The type strain is MJ-SS3T (=KCTC 102114T=KEMB 20189T=JCM 36595T), with reference strain MJ-SS4 (=KCTC 102115=KEMB 20190).

Complete mitochondrial genome of Penicillidia dufourii (Diptera: Hippoboscoidea: Nycteribiidae) and phylogenetic relationship.

Penicillidia dufourii (Westwood 1834) is a specialized parasite categorized under family Nycteribiidae that prefers to parasitize the body surface of various bats under the genus Myotis. Many species of the family Nycteribiidae are carriers of various pathogens; however, research on P. dufourii remains scarce, and studies on its molecular identification and population genetic structure are still lacking. In this study, the complete mitochondrial genome of P. dufourii was elucidated for the first time using Illumina sequencing. The mitochondrial genome is 15,354bp in size and encodes approximately 37 genes, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. Analysis of 13 protein-coding genes revealed that UUA, UCA, CGA, and GGA were the most common codons, while nad4L had the fastest evolutionary rate and cox1 the slowest. Phylogenetic analysis based on the mitochondrial genome indicated that P. dufourii is clustered with other species of the family Nycteribiidae and is most closely related to Nycteribia parvula and Phthiridium szechuanum.

Comparative analysis of 12 water lily plastid genomes reveals genomic divergence and evolutionary relationships in early flowering plants

The aquatic plant Nymphaea, a model genus of the early flowering plant lineage Nymphaeales and family Nymphaeaceae, has been extensively studied. However, the availability of chloroplast genome data for this genus is incomplete, and phylogenetic relationships within the order Nymphaeales remain controversial. In this study, 12 chloroplast genomes of Nymphaea were assembled and analyzed for the first time. These genomes were 158,290–160,042 bp in size and contained 113 non-repeat genes, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. We also report on codon usage, RNA editing sites, microsatellite structures, and new repetitive sequences in this genus. Comparative genomics revealed that expansion and contraction of IR regions can lead to changes in the gene numbers. Additionally, it was observed that the highly variable regions of the chloroplast genome were mainly located in intergenic regions. Furthermore, the phylogenetic tree showed the order Nymphaeales was divided into three families, and the genus Nymphaea can be divided into five (or three) subgenera, with the subgenus Nymphaea being the oldest. The divergence times of nymphaealean taxa were analyzed, with origins of the order Nymphaeales and family Nymphaeaceae being about 194 and 131 million years, respectively. The results of the phylogenetic analysis and estimated divergence times will be useful for future evolutionary studies of basal angiosperm lineages.

The complete chloroplast genome sequence of Lemna turionifera (Araceae)

Lemna turionifera is native to North America and northern Asia, with significant potential for industrial wastewater remediation. The complete nucleotide sequence of the L. turionifera chloroplast genome (cpDNA) was determined. The cpDNA is a circular molecule of 166,606 bp and containing a pair of inverted repeats (IRs) measuting 31,663 bp each. These IRs are flanked by a small single-copy region of 13,542 bp and a large single-copy region of 89,738 bp. The chloroplast genome of L. turionifera consisted of 112 unique genes, including 78 protein-encoding genes, 30 tRNA genes, and four rRNA genes. The phylogenetic analysis utilizing cpDNA provided a well-supported resolution of the relationships among subfamilies within the Araceae family. Our findings indicated a close relationship between L. turionifera and a clade consisting of L. minor, L. japonica, and L. gibba. The availability of the complete chloroplast genome sequence of L. turionifera presents valuable data for future phylogenetic investigations within the Lemnaceae family.

Complete mitochondrial genome of the edible mushroom Singerocybe alboinfundibuliformis (Clitocybaceae, Agaricales)

Singerocybe alboinfundibuliformis (Seok et al.) Yang, Qin & Takah 2014 is an edible mushroom distributed in several East or Southeast Asian countries. Herein, we report the mitochondrial genome of S. alboinfundibuliformis based on Illumina sequencing data. The overall length of the mitochondrial genome is 64,279 bp, with a GC content of 29.0%. It contains 14 typical protein-coding genes, 27 tRNA genes, two rRNA genes, and 13 intergenic ORFs. Most of these genes (39 out of 56) are transcribed at the forward strand, and few (17 out of 56) are transcribed at the reverse strand. Among these genes, only the rnl gene is invaded by an intron, and all other genes are intron-free. Phylogenetic analysis based on mitochondrial amino acid sequences supports the phylogenetic position of S. alboinfundibuliformis in Clitocybaceae, being close to Lepista sordida (Schumach.) Singer 1951. This study serves as a springboard for future investigation on fungal evolution in Clitocybaceae.

Comparative analysis of the mitochondrial genomes of four Dendrobium species (Orchidaceae) reveals heterogeneity in structure, synteny, intercellular gene transfer, and RNA editing.

The genus Dendrobium, part of the Orchidaceae family, encompasses species of significant medicinal, nutritional, and economic value. However, many Dendrobium species are threatened by environmental stresses, low seed germination rates, and overharvesting. Mitochondria generate the energy necessary for various plant life activities. Despite their importance, research on the mitochondrial genomes of Dendrobium species is currently limited. To address this gap, we performed a comprehensive genetic analysis of four Dendrobium species-D. flexicaule, D. nobile, D. officinale, and D. huoshanense-focusing on their mitochondrial and chloroplast genomes to elucidate their genetic architecture and support conservation efforts. We utilized advanced sequencing technologies, including Illumina for high-throughput sequencing and Nanopore for long-read sequencing capabilities. Our findings revealed the multichromosomal mitochondrial genome structures, with total lengths ranging from 596,506 bp to 772,523 bp. The mitochondrial genomes contained 265 functional genes, including 64-69 protein-coding genes, 23-28 tRNA genes, and 3 rRNA genes. We identified 647 simple sequence repeats (SSRs) and 352 tandem repeats, along with 440 instances of plastid-to-mitochondrial gene transfer. Additionally, we predicted 2,023 RNA editing sites within the mitochondrial protein-coding genes, predominantly characterized by cytosine-to-thymine transitions. Comparative analysis of mitochondrial DNA across the species highlighted 25 conserved genes, with evidence of positive selection in five genes: ccmFC, matR, mttB, rps2, and rps10. Phylogenetic assessments suggested a close sister relationship between D. nobile and D. huoshanense, and a similar proximity between D. officinale and D. flexicaule. This comprehensive genomic study provides a critical foundation for further exploration into the genetic mechanisms and biodiversity of Dendrobium species, contributing valuable insights for their conservation and sustainable utilization.

Complete mitochondrial genome of the bird’s nest fungus Nidula shingbaensis (Nidulariaceae, Agaricales)

Bird’s nest fungi involve six different genera, but only one of these genera (i.e. Cyathus) have available mitochondrial genomes (mitogenomes) to date. In this study, we report the first mitogenome in the genus Nidula with Nidula shingbaensis K. Das & R.L. Zhao 2013 as a representative. The mitogenome is a circular molecule of 65,793 bp with a GC content of 26.2%. There are a total of 43 genes, including 14 typical protein-coding genes, 26 tRNA genes, two rRNA genes, and one free-standing intergenic open reading frame (ORF). Three introns (two in cox1 and one in cob) are present in the mitogenome, with each containing an ORF encoding for a LAGLIDADG endonuclease. Phylogenetic analysis based on mitochondrial amino acid sequences confirms the phylogenetic placement of N. shingbaensis in Nidulariaceae in Agaricales. This study serves as a springboard for future investigation on fungal evolution in Nidulariaceae.

The Mitogenome of the Subarctic Octocoral Alcyonium digitatum Reveals a Putative tRNAPro Gene Nested within MutS.

We sequenced and analyzed the complete mitogenome of a Norwegian isolate of the octocoral Alcyonium digitatum using the Ion Torrent sequencing technology. The 18,790 bp circular mitochondrial genome was found to harbor the same set of 17 genes, which encode 14 protein subunits, two structural ribosomal RNAs and one tRNA, as reported in other octocorals. In addition, we detected a new tRNAPro-like gene sequence nested within the MutS protein coding region. This putative tRNA gene feature appears to be conserved among the octocorals but has not been reported previously. The A. digitatum mitogenome was also shown to harbor an optional gene (ORFA) that encodes a putative protein of 191 amino acids with unknown function. A mitogenome-based phylogenetic analysis, presented as a maximum likelihood tree, showed that A. digitatum clustered with high statistical confidence with two other Alcyonium species endemic to the Mediterranean Sea and the Southeast Pacific Ocean.

Comparative mitochondrial genomics analysis of selected species of Schizothoracinae sub family to explore the differences at mitochondrial DNA level

A comprehensive analysis of the whole mitochondrial genomes of the Schizothoracinae subfamily of the family Cyprinidae has been revealed for the first time. The species analyzed include Schizothorax niger, Schizothorax esocinus, Schizothorax labiatus and Schizothorax plagoistomus. The total mitochondrial DNA (mtDNA) length was determined to be 16585 bp, 16583 bp, 16582 bp and 16576 bp, respectively with 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 2 non-coding area genes. The combined mean base compositions of the four species were as follows: A: 29.91 % T: 25.47 % G: 17.65 % C 27.01 %. The range of the GC content is 45–44 %, respectively. All protein coding genes (PCGs) commenced with the typical ATG codon, except for the cytochrome c oxidase subunit 1 (COX1) gene with GTG. The analysis of vital amino acid biosynthesis genes (COX1, ATPase 6, ATPase 8) in four different species revealed no significant differences. All 13 PCGs had Ka/Ks ratios that were all lesser than one, demonstrating purifying selection on those molecules. These tRNA genes were predicted to fold into the typical cloverleaf secondary structures with normal base pairing and ranged in size from 66 to 75 nucleotides. Additionally, the phylogenetic tree analysis revealed that S. esocinus species that was most alike to S. labiatus. This study provides critical data for phylogenetic analysis of the Schizothoracinae subfamily, which will help to resolve taxonomic difficulties and identify evolutionary links. Detailed mtDNA data are an invaluable resource for studying genetic diversity, population structure, and gene flow. Understanding genetic makeup can help inform conservation plans, identify unique populations, and track genetic variation to ensure effective preservation.

The Complete Mitogenome of Apostasia fujianica Y.Li & S.Lan and Comparative Analysis of Mitogenomes across Orchidaceae.

Apostasia fujianica belongs to the genus Apostasia and is part of the basal lineage in the phylogenetic tree of the Orchidaceae. Currently, there are only ten reported complete mitochondrial genomes in orchids, which greatly hinders the understanding of mitochondrial evolution in Orchidaceae. Therefore, we assembled and annotated the mitochondrial genome of A. fujianica, which has a length of 573,612 bp and a GC content of 44.5%. We annotated a total of 44 genes, including 30 protein-coding genes, 12 tRNA genes, and two rRNA genes. We also performed relative synonymous codon usage (RSCU) analysis, repeat sequence analysis, intergenomic transfer (IGT) analysis, and Ka/Ks analysis for A. fujianica and conducted RNA editing site analysis on the mitochondrial genomes of eight orchid species. We found that most protein-coding genes are under purifying selection, but nad6 is under positive selection, with a Ka/Ks value of 1.35. During the IGT event in A. fujianica's mitogenome, the trnN-GUU, trnD-GUC, trnW-CCA, trnP-UGG, and psaJ genes were identified as having transferred from the plastid to the mitochondrion. Compared to other monocots, the family Orchidaceae appears to have lost the rpl10, rpl14, sdh3, and sdh4 genes. Additionally, to further elucidate the evolutionary relationships among monocots, we constructed a phylogenetic tree based on the complete mitogenomes of monocots. Our study results provide valuable data on the mitogenome of A. fujianica and lay the groundwork for future research on genetic variation, evolutionary relationships, and breeding of Orchidaceae.

A de novo novel variant in the MT-TD gene is associated with prominent extra-neurologic manifestations.

Defects in the mitochondrial tRNA genes cause a group of highly clinically and genetically heterogeneous disorders, which poses a challenge for clinical identification and genetic diagnosis. Here, we present a pre-school boy with a novel MT-TD variant m.7560T>C at the heteroplasmy level of 76.53% in blood, 93.34% in urine sediments, and absent in the healthy mother's blood and urine. Besides convulsions, brain magnetic resonance imaging abnormalities and high plasma lactate, the boy presented with the prominent extra-neurologic phenotype including steroid-resistant nephrotic syndrome associated with focal segmental glomerulosclerosis characterized by abnormal mitochondria in podocytes, cortical blindness, and pancreatitis. To our knowledge, this is the unique case with MT-TD m.7560T>C-related multi-organ impairments, which expands the phenotypic and mutational spectrum of primary mitochondrial diseases.