Next Article in Journal
AMPK Deficiency Increases DNA Methylation and Aggravates Colorectal Tumorigenesis in AOM/DSS Mice
Previous Article in Journal
Genome-Wide Identification of the Whirly Gene Family and Its Potential Function in Low Phosphate Stress in Soybean (Glycine max)
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

The Whole Mitochondrial Genome Sequence of Dendrobium loddigesii Rolfe, an Endangered Orchid Species in China, Reveals a Complex Multi-Chromosome Structure

Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, China
*
Author to whom correspondence should be addressed.
Genes 2024, 15(7), 834; https://doi.org/10.3390/genes15070834
Submission received: 28 May 2024 / Revised: 18 June 2024 / Accepted: 19 June 2024 / Published: 25 June 2024
(This article belongs to the Section Plant Genetics and Genomics)

Abstract

:
Dendrobium loddigesii is a precious traditional Chinese medicine with high medicinal and ornamental value. However, the characterization of its mitochondrial genome is still pending. Here, we assembled the complete mitochondrial genome of D. loddigesii and discovered that its genome possessed a complex multi-chromosome structure. The mitogenome of D. loddigesii consisted of 17 circular subgenomes, ranging in size from 16,323 bp to 56,781 bp. The total length of the mitogenome was 513,356 bp, with a GC content of 43.41%. The mitogenome contained 70 genes, comprising 36 protein-coding genes (PCGs), 31 tRNA genes, and 3 rRNA genes. Furthermore, we detected 403 repeat sequences as well as identified 482 RNA-editing sites and 8154 codons across all PCGs. Following the sequence similarity analysis, 27 fragments exhibiting homology to both the mitogenome and chloroplast genome were discovered, accounting for 9.86% mitogenome of D. loddigesii. Synteny analysis revealed numerous sequence rearrangements in D. loddigesii and the mitogenomes of related species. Phylogenetic analysis strongly supported that D. loddigesii and D. Amplum formed a single clade with 100% bootstrap support. The outcomes will significantly augment the orchid mitochondrial genome database, offering profound insights into Dendrobium’s intricate mitochondrial genome architecture.

1. Introduction

The genus Dendrobium, belonging to the Orchidaceae family, comprises approximately 1500 species worldwide, with about 80 species native to China [1]. The stems of several plants within this genus have been utilized for centuries in traditional Chinese medicine [2]. D. loddigesii is a perennial epiphytic herb in the Orchidaceae family. It is primarily distributed in provinces such as Guizhou, Guangxi, Yunnan, and Guangdong in China [3]. The stems of D. loddigesii are a commonly used and precious Chinese medicinal herb, which has anti-inflammatory, antimicrobial, antioxidant, antitumor, and immunomodulatory effects [3,4,5]. It mainly contains polysaccharides, alkaloids, and other chemical components [6]. Due to the low germination rate of D. loddigesii seeds in natural environments, as well as excessive harvesting and utilization, the germplasm resources and wild populations of D. loddigesii have rapidly decreased [7]. Therefore, it is necessary to analyze the genetic relationship through mitochondrial sequencing to provide a theoretical basis for the sustainable utilization and protection of D. loddigesii germplasm resources.
The plant mitochondrial genome exhibits semi-autonomous genetic characteristics and serves as a crucial cellular organelle for respiratory metabolism and the supply of energy for life activities [8,9]. Compared with other organelle genomes, the mitochondrial genome is relatively large and has frequent structural changes, such as genome rearrangement, repeat sequence recombination, transfer, deletion, and repetition of foreign DNA [10]. This complexity makes it more challenging to assemble the mitochondrial genome [11]. While most plant mitogenomes are typically circular, the actual physical architecture of these genomes shows a diverse array of structures, including circles, linear molecules, and intricate branching patterns [12,13]. Furthermore, investigations into the structure of plant mitogenomes are predominantly focused on model species, including Arabidopsis thaliana [14], tobacco (Y Sugiyama, 2005) [15], and maize [16], which limits the application of generalized inferences about the plant mitochondrial genome evolution and function. Currently, studies have found that Dendrobium mitochondria exhibit a multiple chromosome phenomenon. However, only four mitochondrial genomes of Dendrobium have been published, including D. wilsonii, D. Henanense, D. wilsonii, and D. Henanense [17]. Hence, more mitogenomes should be explored to enhance our understanding of mitochondrial structures of Dendrobium. In this study, we aimed to sequence, assemble, and annotate the complete mitogenome of D. loddigesii. A comprehensive analysis of repeat sequences, synonymous codon usage, and RNA editing was performed, and synteny and phylogenetic relationships were compared with several previously reported mitochondria genomes. Our findings aim to demonstrate that the plant mitochondrial genome comprises various sequence elements characterized by complex structures.

2. Materials and Methods

2.1. Plant Materials and DNA Sequencing

Fresh leaves of D. loddigesii were rapidly collected and preserved at −80 °C. Genomic DNA was extracted using the modified CTAB method [18]. The qualified DNA samples were then sequenced on the Illumina NovaSeq 6000 platform (Genepioneer Biotechnologies Co., Ltd.; Nanjing, China).

2.2. Assembly and Annotation

For acquiring a high-quality D. loddigesii mitochondrial genome, the second-generation data were used to extract high-quality reads, while the original third-generational data were employed for correction. Then, the genome assembly was conducted utilizing NextPolish v1.3.1 (https://github.com/Nextomics/NextPolish, accessed on 18 August 2023). The annotation process for the draft mitochondrial genome of D. loddigesii followed established procedures [19]. Encoded proteins and rRNAs were annotated through Blastn searches of published plant mitochondrial sequences at the National Center for Biotechnology Information (NCBI). Transfer RNA genes (tRNAs) were annotated using tRNA scan-SE [20]. An ORF finder was utilized to analyze open reading frames (ORFs), and an Organellar Genome DRAW was employed for the construction of the mitochondrial genome [21].

2.3. Repeat Sequences Analysis

The examination of repeat structures, including forward (F), reverse (R), complement (C), and palindromic (P) repeats, was carried out utilizing vmatch v2.3.0 software (http://www.vmatch.de/, accessed on 18 August 2023). The MicroSAtellite identification tool (Misa) was used to explore mitochondrial SSR [22]. The parameters employed for the analysis were as follows: mononucleotides repeated at least 8 times, dinucleotides repeated at least 5 times, trinucleotides repeated at least 4 times, and tetra-, penta-, and hexanucleotides repeated at least 3 times. Tandem repeats were found using Tandem Repeats Finder (http://tandem.bu.edu/trf/trf.submit.options.html, accessed on 18 August 2023) [23].

2.4. Synonymous Codon Usage Analysis

To assess the synonymous codon usage patterns within the mitochondrial genome, we employed the relative synonymous codon usage (RSCU) using the CodonW1.4.4 (http://codonw.sourceforge.net/, accessed on 16 August 2023) [24]. Subsequently, the R package (3.5.1) ggplot2 was utilized to generate visualizations of the RSCU data, providing a clear and informative representation of the codon usage patterns.

2.5. RNA Editing Analyses and Chloroplast to Mitochondrion DNA Transfer

To identify RNA-editing sites within the mitochondrial genes of D. loddigesii, the plant mitochondrial gene-encoding proteins were used as the reference proteins. The plant predictive RNA editor (PREP) suite (http://prep.unl.edu/, accessed on 16 August 2023) was employed to analyze the editing sites [25]. The chloroplast genome sequence of D. loddigesii (accession number: NC_036355.1) was retrieved from the NCBI Organelle Genome Resources Database. The homologous fragments were identified utilizing BLAST v2.10.1 software.

2.6. Synteny and Phylogenetic Analysis

A dot plot comparing pairwise sequences was generated to visualize conservative co-linear blocks. Furthermore, a multiple synteny plot was created to depict the mitogenome of D. loddigesii in comparison with related species. For phylogenetic tree analysis, we utilized the conserved PCGs extracted from the mitochondrial genome of D. loddigesii along with those from 15 other taxa. The 15 mitochondrial genomes were obtained from NCBI Organelle Genome Resources database, and the conserved PCGs were extracted using the Tbtools2.07 software. The gene sequences were then aligned using the Muscle v5 software, and a Neighbor-joining (NJ) tree was constructed using the Mega 11.0 software [26].

3. Results

3.1. Genomic Features of the D. loddigesii Mitogenome

We used Illumina and Nanopore sequencing platforms to acquire basic data to assemble the mitochondrial genome. Among them, raw Illumina data were 15.61 Gb and Nanopore raw data were 22.82 Gb, with an N50 of 21,378 bp and an average read length of 7140 bp (Supplementary Tables S1 and S2). By aligning the Illumina and Nanopore sequencing, the graphical assembly became 17 circular contigs (Figure 1, Table 1), which depicted the entire mitogenomes of D. loddigesii. These obtained contigs were referred to as chromosomes in this context. The total length of the D. loddigesii mitogenome was 513,356 bp, with a GC content of 43.41%. The two largest chromosomes, measuring 56,781 bp and 53,030 bp, respectively, comprised approximately 21.49% of the total size of the mitogenome. On the other hand, the smallest fragment was 16,323 bp and accounted for approximately 3.18% of the mitogenome. The mitochondrial genome had an average GC content of 43.46%, with the highest content reaching 45.93% and the lowest content being 38.27%.
The complete mitochondrial genome of D. loddigesii was annotated with 70 genes, including 36 PCGs, 31 tRNA genes, and 3 rRNA genes (Table S3). The PCGs can be classified as ATP synthases (atp1, atp4, atp6, atp8, and atp9), cytochrome c biogenesis (ccmB, ccmC, ccmFc, and ccmFn), ubiquinol cytochrome c reductases (1 gene, cob), maturases (matR), cytochrome C oxidases (cox1, cox2, and cox3), transport membrane proteins (mttB), NADH dehydrogenases (nad1, nad2, nad3, nad4, nad4L, nad5, nad6, nad7, and nad9), a large subunit of ribosome (rpl5), small subunits of ribosome (rps10, rps12, rps13, rps14, and rps7), and succinate dehydrogenase (sdh4) (Table 2). Among the 36 PCGs, 8 contained introns: ccmFc and rps10 had a single intron, cox2 contained two introns, nad4 contained three introns, and nad1, nad2, nad5, and nad7 had four introns. Among the 31 tRNA proteins, 7 tRNA genes (trnC-GCA, trnE-TTC, trnL-GAA, trnM-CAT, trnN-GTT, trnS-GCT, and trnY-GTA) showed the multi-copy phenomenon, of which 1 gene, trnM-CAT included up to 4 copies. The two genes, trnA-TGC and trnI-TAT, had an intron.

3.2. Repeat Sequence Analysis

A total of 403 repeats were found in the D. loddigesii mitochondrial genome, including 221 dispersed sequences, 146 SSRs, and 36 tandem sequences (Figure 2, Table S4). The dispersed sequences included 90 forward repeat sequences and 131 palindromic repeat sequences (Table S5). The largest forward repeat sequence was 631 bp in length, while the palindromic repeat sequence had a size of 467 bp. The total length of the dispersed repeat sequences was 24,272 bp, accounting for 4.73% of the total length of the mitochondrial genome. Moreover, among 146 SSRs, 48 mononucleotide, 34 dinucleotide, 18 trinucleotide, 35 tetranucleotide, 8 pentanucleotide, and 3 hexanucleotide repeat types were explored. Among the mononucleotide repeat types, the repeats of A/T were the most ordinary, and only one type was C/C repeats (Table S6). A total of 36 tandem repeats were detected, ranging from 6 to 34 bp in length, with a matching degree surpassing 78% (Table S7). Chromosomes 3, 5, and 7 exhibited the highest occurrence of tandem repeats, whereas chromosomes 9, 10, 11, 16, and 17 displayed an absence of such repeats. This observation indicated an uneven distribution of tandem repeats across the mitochondrial genome of D. loddigesii.

3.3. Codon Usage Analysis

The relative synonymous codon usage (RSCU) is generally thought to reflect the result of biological natural selection, with RSCU values exceeding 1 indicating a preference for specific amino acid codons [27]. Codon usage analysis was conducted on 36 PCGs within D. lodigesii mitochondria. The results revealed that all genes were encoded by 8154 codons, encoding 20 amino acids (Figure 3, Table S8). Notably, the RSCU values of 4338 codons were greater than 1, indicating that they were used more frequently. Furthermore, in addition to the high frequency of use of the three-stop codons, UAU, UGA, and UAG, a general preference for specific codons was observed in mitochondrial PCGs. For example, GCA, GCC, GCG, and GCU were the most commonly used codons in D. lodigesii.

3.4. RNA Editing Site Analysis

In higher plants, RNA editing is a post-transcriptional process necessary for mitochondrial gene expression [28]. In the D. loddigesii mitochondria, 538 RNA-editing sites were predicted in PCG genes (Figure 4). Among those PCG genes, the most RNA-editing sites were the nad4 gene (56 sites, 10.41%) followed by the ccmFn gene with 40 RNA editing sites. The minimum number of RNA-editing sites were the rps14 and rps7 genes, with only two and three editing sites, respectively. In addition, further analysis showed that 262 RNA-editing sites (48.70%) of the amino acids changed from hydrophilic to hydrophobic, 156 sites (29.00%) from hydrophobic to hydrophobic, 70 sites (13.01%) from hydrophilic to hydrophilic, 48 sites (8.92%) from hydrophobic to hydrophilic, and only 2 editing sites (0.37%) of amino acids became stop codons (X) (Table 3). The studies also found that 230 editing sides (42.74%) of the amino acids were changed to leucine (L), showing a leucine tendency.

3.5. Chloroplast to Mitochondrion DNA Transfer

Sequence similarity analysis showed that there were 27 homologous fragments shared between mitochondrial and chloroplast genomes, with a total length of 50,632 bp, accounting for 9.86% of the total length of the D. lodigesii mitogenome (Figure 5, Table 4). Among these, six fragments exceeded 1000 bp, with fragments 1 and 2 being the longest at 8595 bp, while the smallest fragment was 23 for 29 bp. Through annotation of these homologous sequences, 18 integrated chloroplast-derived genes were identified, specifically including trnL-CAA, trnR-ACG, trnN-GUU, trnV-GAC, trnA-UGC, trnL-UAG, trnS-GGA, trnT-UGU, trnG-GCC, trnM-CAU, trnT-GGU, trnE-UUC, trnY-GUA, trnW-CCA, trnP-UGG, trnF-GAA, trnQ-UUG, and trnS-GCU, and two incomplete rRNA genes (rrn18 and rrn26) were also discovered. Notably, all transferred genes were tRNA genes and partial rRNA genes, and no PCGs were found, which indicated that tRNA genes were more conserved in the D. lodigesii plastid genome.

3.6. Synteny and Phylogenetic Analysis

Sequence similarity was used to map the multiple synteny plot of D. lodigesii with six related species (Table S9). A large number of syntenic collinear blocks were found between D. lodigesii and D. amplum. The dot plot analysis suggested that only sporadic collinear regions existed between the mitogenomes of D. lodigesii and the other five mitochondrial genomes (Phoenix dactylifera, Allium cepa, Cocos nucifera, Asparagus officinalis, and A. officinalis), showing poor collinearity (Figure 6). Moreover, the analysis also found that the co-linear blocks were not aligned identically in the mitogenomes of D. lodigesii and D. Amplum (Figure 7), which may suggest that the mitogenome of D. lodigesii had undergone substantial genomic rearrangements, resulting in a highly variable and unconserved structure.
To determine the phylogenetic location of D. lodigesii, the mitochondrial genome sequences of 15 angiosperms were retrieved from GenBank (Table S10). The sequences were based on 25 conserved PCGs, which were to establish a phylogenetic tree, using Aegilops speltoides as the outgroup (Figure 8). The phylogenetic tree provided robust evidence, with 100% bootstrap support, for a close phylogenetic affinity between D. lodigesii and D. amplum. Both species are native to south-central and south-eastern China, and phylogenetic analysis further confirms this geographical proximity.

4. Discussion

4.1. Characterization of the D. lodigesii Mitogenome

Mitochondria play an important role as organelles within eukaryotic cells [29]. Unlike animal cells, plant mitochondrial DNA exhibits amazing structural diversity, with its structure being able to rapidly switch between linear, circular, and branched forms within the organism [30]. Generally, plant mitochondria are usually assembled into a large circle structure, but their true morphology may consist of smaller circles combined with branching DNA molecules [31]. In this study, we assembled the mitochondria of D. lodigesii, which contained 17 chromosomes and exhibited a multi-chromosome structure. The Dendrobium genus is generally polychromosome, with the mitochondrial genome sequences of D. wilsonii and D. henenense possessing 22 and 24 independent chromosome structures, respectively [32]. The rapid acquisition or loss of chromosomes has been postulated as a pivotal evolutionary process that explains these observed disparities [16]. The D. loddigesii mitogenome was annotated with 70 genes, which was similar to the number in D. wilsonii (77) and D. henanense (83) [32]. However, the most significant differences among the three mitogenomes were primarily observed in the tRNA genes. Specifically, the mitogenome of D. loddigesii contained 31 tRNA genes, while the mitogenomes of D. Wilsonii and D. henanense had 33 and 40 tRNA genes, respectively. These findings indicated that Dendrobium species exhibited the greatest variation in the number of tRNA genes within their mitochondrial genomes.

4.2. The Repeat Sequences in the D. lodigesii Mitogenome

The repeat sequences are potentially important markers for population and evolutionary studies [33]. In this study, a total of 403 repeat sequences were identified in the D. loddigesii mitochondrial genome, including 146 SSRs. SSRs have the advantages of codominance, high reproducibility, and the requirement of a small amount of DNA template [34,35]. These features enable their application in various scenarios, including DNA fingerprinting, gene mapping, and marker-assisted breeding [36,37,38].

4.3. RNA Editing in the D. lodigesii Mitogenome

In plants, RNA editing is a pivotal process that significantly contributes to mitochondrial gene expression and functionality [39]. Numerous RNA editing events have the potential to introduce changes in RNA sequences, ultimately resulting in variations in the amino acid sequences of the translated protein products [40,41]. A total of 538 RNA-editing sites were detected in D. loddigesii mitochondria. Consistent with observations in other plant species [42,43,44], a majority of RNA-editing sites in this mitochondrion occurred at the first or second positions within the RNA sequence. RNA editing events at two specific sites lead to the creation of stop codons in D. loddigesii mitochondria, which is frequently linked to the production of proteins that exhibit high conservation to those identified in other species [40]. This mechanism facilitates efficient gene expression within mitochondria.

4.4. MTPTs in the D. lodigesii Mitogenome

Horizontal gene transfer (HGT) occurs between the genomes of organelles (such as plastids and mitochondria) and the nuclear genomes of plant cells, and it is a general phenomenon that significantly impacts plant evolution [45]. One of the more intriguing phenomena in plant genetics is the transformation of DNA fragments from plastids into mitochondrial genomes, referred to as plastid-to-mitochondrial transfers (MTPTs) [46]. These transfers involve the movement of genetic material, typically short DNA sequences, from the plastid genome into the mitochondrial genome [47]. In this study, eighteen complete tRNA genes, including trnL-CAA, trnR-ACG, trnN-GUU, trnV-GAC, trnA-UGC, trnL-UAG, trnS-GGA, trnT-UGU, trnG-GCC, trnM-CAU, trnT-GGU, trnE-UUC, trnY-GUA, trnW-CCA, trnP-UGG, trnF-GAA, trnQ-UUG, and trnS-GCU, were found to migrate from the chloroplast to the mitogenome in D. lodigesii. Interestingly, the mitogenome of D. lodigesii harbored only 13 native tRNA genes, suggesting that over half of its tRNA genes had undergone HGT from the chloroplast. During the entire evolutionary process, the horizontal transfer of tRNA genes from the chloroplast to the mitochondrion in D. lodigesii had resulted in the acquisition of functionally conserved tRNAs, which were prevalent across the angiosperms [48]. Among the tRNA genes’ horizontally transferred events, trnW-CCA frequently appeared in the mitochondrial genomes of diverse angiosperms [49,50]. Prior research had demonstrated that trnM-CAU possessed a potential functional role in plant mitochondria genomes, suggesting that it underwent transfer during an initial phase of evolutionary development [51]. Both tRNA genes, trnW-CCA, and trnM-CAU, were also discovered as part of the level gene transfer involving the organelles of D. lodigesii.

4.5. Synteny and Phylogenetic Analyses in the D. lodigesii Mitogenome

We conducted homologous collinear alignments to delve into the rearrangement and conservative sequence patterns within the mitochondrial genome. The findings indicated that D. lodigesii and several other genera (Phoenix, Allium, Cocos, Asparagus, and Chlorophytum) displayed low collinearity, whereas D. amplum exhibited high collinearity (71.42%). This suggests that closely related species tended to have longer collinear regions, while distantly related genomes showed poorer collinearity [52]. Moreover, analysis of collinear alignments revealed inconsistent alignment of collinear blocks in the mitogenomes of D. lodigesii and D. Amplum, which may suggest that the mitogenome had undergone substantial genomic rearrangements, resulting in a highly variable and unconserved structure. This outcome aligned with earlier findings from mitochondrial collinearity analysis of D. Wilsonii and D. Henanense, demonstrating a substantial presence of mitochondrial rearrangements in both Dendrobium species [32].
Here, we built the phylogeny of Dendrobium using conserved mitochondrial PCG sequences from 15 angiosperm species retrieved from GenBank. Unlike chloroplast and nuclear genomes, mitogenomes are rarely used for phylogenetic analysis in higher plants, primarily due to their slow mutation frequency, high rate of genome recombination, and integration of exogenous DNA [53,54]. However, in this study, the D. lodigesii clade was sister to the D. Amplum clade with strong support (100%) in the present study, and the issue of weakly supported nodes in mitochondrial gene trees has been well addressed. These results suggest that PCG genes in plant mitochondrial genomes can be used for phylogenetic analysis.

5. Conclusions

In this study, we have successfully assembled and annotated the mitogenome of an orchid plant, D. loddigesii, revealing a complex multi-chromosome structure. The total length of D. loddigesii mitogenome was 513,356 bp, which consisted of 17 circular chromosomes. The genome was annotated with 70 genes, including 36 PCGs, 31 tRNA genes, and 3 rRNA genes. The repeat sequences, codon preference, and RNA-editing sites were also characterized. In addition, we also identified MTPTs and performed synteny and phylogenetic analyses to gain a deeper insight into the evolutionary trajectory of the mitogenome in Dendrobium. The results of this research further validate the intricate structure of mitogenomes in the orchid family.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/genes15070834/s1, Table S1: Statistics of Illumina sequencing data. Table S2: Statistics of Nanopore sequencing data. Table S3: The annotation of the D. loddigesii mitogenome. Table S4: The repeat sequences in the D. loddigesii mitogenome. Table S5: the dispersed sequences in the D. loddigesii mitogenome. Table S6: SSRs in the D. loddigesii mitogenome. Table S7: The tandem sequences in the D. loddigesii mitogenome. Table S8. Codon usage analysis in the D. loddigesii mitogenome. Table S9: Species list used for synteny analysis. Table S10: Species list used for phylogenetic analysis.

Author Contributions

S.W., methodology, resources, writing—review and editing; W.T., writing—original draft preparation, software, visualization, funding acquisition; D.Y., investigation; X.Z., project administration; Z.L., data curation; H.C., formal analysis; F.H., supervision. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by special funds for basic research expenses of central public welfare research institutes (Grant No. GYZX220201).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The sequencing data for Illumina and Nanopore platforms and the mitogenome sequences have been deposited in NCBI (https://www.ncbi.nlm.nih.gov/, accessed on 28 May 2024) with accession numbers PRJNA1113802, PRJNA1113802, and PP829175-PP829191.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Yang, D.; Cheng, Z.-Q.; Yang, L.; Hou, B.; Yang, J.; Li, X.-N.; Zi, C.-T.; Dong, F.-W.; Liu, Z.-H.; Zhou, J. Seco-dendrobine-type alkaloids and bioactive phenolics from Dendrobium findlayanum. J. Nat. Prod. 2018, 81, 227–235. [Google Scholar] [CrossRef] [PubMed]
  2. Zhou, X.-M.; Zheng, C.-J.; Gan, L.-S.; Chen, G.-Y.; Zhang, X.-P.; Song, X.-P.; Li, G.-N.; Sun, C.-G. Bioactive phenanthrene and bibenzyl derivatives from the stems of Dendrobium nobile. J. Nat. Prod. 2016, 79, 1791–1797. [Google Scholar] [CrossRef] [PubMed]
  3. Ma, R.-J.; Yang, L.; Bai, X.; Li, J.-Y.; Yuan, M.-Y.; Wang, Y.-Q.; Xie, Y.; Hu, J.-M.; Zhou, J. Phenolic constituents with antioxidative, tyrosinase inhibitory and anti-aging activities from Dendrobium loddigesii Rolfe. Nat. Prod. Bioprospecting 2019, 9, 329–336. [Google Scholar] [CrossRef] [PubMed]
  4. Pharmacopoeia, C. Pharmacopoeia of the People’s Republic of China; People’s Medical Publishing House: Beijing, China, 2015. [Google Scholar]
  5. Zhang, K.-H.; Wang, M.-Q.; Wei, L.-L.; Feng, C.-J.; Zhang, Y.-S.; Teng, J.-B. Investigation of the Effects and Mechanisms of Dendrobium loddigesii Rolfe Extract on the Treatment of Gout. Evid. Based Complement. Altern. Med. 2020, 2020, 4367347. [Google Scholar] [CrossRef] [PubMed]
  6. Li, M.; Hirata, Y.; Xu, G.; Niwa, M.; Wu, H. Studies on the chemical constituents of Dendrobium loddigesii rolfe. Yao Xue Xue Bao Acta Pharm. Sin. 1991, 26, 307–310. [Google Scholar]
  7. Shen, X.; Liu, C.; Pan, K. Reproductive Biological Characteristics of Dendrobium Species; CRC Press: Boca Raton, FL, USA, 2014. [Google Scholar]
  8. Singh, S.; Naik, J.; Pandey, A. Genetics of Plant Organelles: Plastid and Mitochondrial Genomes. In Plant Genomics for Sustainable Agriculture; Springer: Berlin/Heidelberg, Germany, 2022; pp. 313–330. [Google Scholar]
  9. Ye, N.; Wang, X.; Li, J.; Bi, C.; Xu, Y.; Wu, D.; Ye, Q. Assembly and comparative analysis of complete mitochondrial genome sequence of an economic plant Salix suchowensis. PeerJ 2017, 5, e3148. [Google Scholar] [CrossRef] [PubMed]
  10. Chevigny, N.; Schatz-Daas, D.; Lotfi, F.; Gualberto, J.M. DNA repair and the stability of the plant mitochondrial genome. Int. J. Mol. Sci. 2020, 21, 328. [Google Scholar] [CrossRef] [PubMed]
  11. Nosek, J.; Tomáška, Ľ. Mitochondrial genome diversity: Evolution of the molecular architecture and replication strategy. Curr. Genet. 2003, 44, 73–84. [Google Scholar] [CrossRef]
  12. Backert, S.; Börner, T. Phage T4-like intermediates of DNA replication and recombination in the mitochondria of the higher plant Chenopodium album (L.). Curr. Genet. 2000, 37, 304–314. [Google Scholar] [CrossRef] [PubMed]
  13. Zardoya, R. Recent advances in understanding mitochondrial genome diversity. F1000Research 2020, 9. [Google Scholar] [CrossRef]
  14. Unseld, M.; Marienfeld, J.R.; Brandt, P.; Brennicke, A. The mitochondrial genome of Arabidopsis thaliana contains 57 genes in 366,924 nucleotides. Nat. Genet. 1997, 15, 57–61. [Google Scholar] [CrossRef] [PubMed]
  15. Sugiyama, Y.; Watase, Y.; Nagase, M.; Makita, N.; Yagura, S.; Hirai, A.; Sugiura, M. The complete nucleotide sequence and multipartite organization of the tobacco mitochondrial genome: Comparative analysis of mitochondrial genomes in higher plants. Mol. Gene. Genom. 2005, 272, 603–615. [Google Scholar] [CrossRef] [PubMed]
  16. Clifton, S.W.; Minx, P.; Fauron, C.M.-R.; Gibson, M.; Allen, J.O.; Sun, H.; Thompson, M.; Barbazuk, W.B.; Kanuganti, S.; Tayloe, C. Sequence and comparative analysis of the maize NB mitochondrial genome. Plant Physiol. 2004, 136, 3486–3503. [Google Scholar] [CrossRef] [PubMed]
  17. Wang, M.T.; Hou, Z.Y.; Li, C.; Yang, J.P.; Niu, Z.T.; Xue, Q.Y.; Liu, W.; Ding, X.Y. Rapid structural evolution of Dendrobium mitogenomes and mito-nuclear phylogeny discordances in Dendrobium (Orchidaceae). J. Syst. Evol. 2023, 61, 790–805. [Google Scholar] [CrossRef]
  18. Doyle, J.J.; Doyle, J.L. A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochem. Bull. 1987, 19, 11–15. [Google Scholar]
  19. Qiao, Y.; Zhang, X.; Li, Z.; Song, Y.; Sun, Z. Assembly and comparative analysis of the complete mitochondrial genome of Bupleurum chinense DC. BMC Genom. 2022, 23, 664. [Google Scholar] [CrossRef] [PubMed]
  20. Chan, P.P.; Lowe, T.M. tRNAscan-SE: Searching for tRNA Genes in Genomic Sequences; Springer: Berlin/Heidelberg, Germany, 2019. [Google Scholar]
  21. Greiner, S.; Lehwark, P.; Bock, R. OrganellarGenomeDRAW (OGDRAW) version 1.3. 1: Expanded toolkit for the graphical visualization of organellar genomes. Nucleic Acids Res. 2019, 47, W59–W64. [Google Scholar] [CrossRef] [PubMed]
  22. Beier, S.; Thiel, T.; Münch, T.; Scholz, U.; Mascher, M. MISA-web: A web server for microsatellite prediction. Bioinformatics 2017, 33, 2583–2585. [Google Scholar] [CrossRef]
  23. Benson, G. Tandem repeats finder: A program to analyze DNA sequences. Nucleic Acids Res. 1999, 27, 573–580. [Google Scholar] [CrossRef]
  24. Peden, J.F. Analysis of Codon Usage. Ph.D. Thesis, University of Nottingham, Nottingham, UK, 2000; pp. 73–74. [Google Scholar]
  25. Chateigner-Boutin, A.-L.; Small, I. Plant RNA editing. RNA Biol. 2010, 7, 213–219. [Google Scholar] [CrossRef]
  26. Minh, B.Q.; Schmidt, H.A.; Chernomor, O.; Schrempf, D.; Woodhams, M.D.; Von Haeseler, A.; Lanfear, R. IQ-TREE 2: New models and efficient methods for phylogenetic inference in the genomic era. Mol. Biol. Evol. 2020, 37, 1530–1534. [Google Scholar] [CrossRef] [PubMed]
  27. Zhou, M.; Tong, C.; Shi, J. Analysis of codon usage between different poplar species. J. Genet. Genom. 2007, 34, 555–561. [Google Scholar] [CrossRef] [PubMed]
  28. Salojärvi, J.; Smolander, O.-P.; Nieminen, K.; Rajaraman, S.; Safronov, O.; Safdari, P.; Lamminmäki, A.; Immanen, J.; Lan, T.; Tanskanen, J. Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch. Nat. Genet. 2017, 49, 904–912. [Google Scholar] [CrossRef] [PubMed]
  29. Omelchenko, D.O.; Makarenko, M.S.; Kasianov, A.S.; Schelkunov, M.I.; Logacheva, M.D.; Penin, A.A. Assembly and analysis of the complete mitochondrial genome of Capsella bursa-pastoris. Plants 2020, 9, 469. [Google Scholar] [CrossRef] [PubMed]
  30. Zhou, P.; Zhang, Q.; Li, F.; Huang, J.; Zhang, M. Assembly and comparative analysis of the complete mitochondrial genome of Ilex metabaptista (Aquifoliaceae), a Chinese endemic species with a narrow distribution. BMC Plant Biol. 2023, 23, 393. [Google Scholar] [CrossRef] [PubMed]
  31. Chen, T.-C.; Su, Y.-Y.; Wu, C.-H.; Liu, Y.-C.; Huang, C.-H.; Chang, C.-C. Analysis of mitochondrial genomics and transcriptomics reveal abundant RNA edits and differential editing status in moth orchid, Phalaenopsis aphrodite subsp. formosana. Sci. Hortic. 2020, 267, 109304. [Google Scholar] [CrossRef]
  32. Wang, M.; Yu, W.; Yang, J.; Hou, Z.; Li, C.; Niu, Z.; Zhang, B.; Xue, Q.; Liu, W.; Ding, X. Mitochondrial genome comparison and phylogenetic analysis of Dendrobium (Orchidaceae) based on whole mitogenomes. BMC Plant Biol. 2023, 23, 586. [Google Scholar] [CrossRef] [PubMed]
  33. Wan, Q.H.; Wu, H.; Fujihara, T.; Fang, S.G. Which genetic marker for which conservation genetics issue? Electrophoresis 2004, 25, 2165–2176. [Google Scholar] [CrossRef] [PubMed]
  34. Guichoux, E.; Lagache, L.; Wagner, S.; Chaumeil, P.; Léger, P.; Lepais, O.; Lepoittevin, C.; Malausa, T.; Revardel, E.; Salin, F. Current trends in microsatellite genotyping. Mol. Ecol. Resour. 2011, 11, 591–611. [Google Scholar] [CrossRef]
  35. Li, L.; Fang, Z.; Zhou, J.; Chen, H.; Hu, Z.; Gao, L.; Chen, L.; Ren, S.; Ma, H.; Lu, L. An accurate and efficient method for large-scale SSR genotyping and applications. Nucleic Acids Res. 2017, 45, e88. [Google Scholar] [CrossRef]
  36. Børsting, C.; Morling, N. Next generation sequencing and its applications in forensic genetics. Forensic Sci. Int. Genet. 2015, 18, 78–89. [Google Scholar] [CrossRef] [PubMed]
  37. Kadirvel, P.; Senthilvel, S.; Geethanjali, S.; Sujatha, M.; Varaprasad, K. Genetic markers, trait mapping and marker-assisted selection in plant breeding. In Plant Biology and Biotechnology, Volume II: Plant Genomics and Biotechnology; Springer: New Delhi, India, 2015; pp. 65–88. [Google Scholar] [CrossRef]
  38. Hasan, N.; Choudhary, S.; Naaz, N.; Sharma, N.; Laskar, R.A. Recent advancements in molecular marker-assisted selection and applications in plant breeding programmes. J. Genet. Eng. Biotechnol. 2021, 19, 128. [Google Scholar] [CrossRef] [PubMed]
  39. Tang, W.; Luo, C. Molecular and functional diversity of RNA editing in plant mitochondria. Mol. Biotechnol. 2018, 60, 935–945. [Google Scholar] [CrossRef] [PubMed]
  40. Edera, A.A.; Gandini, C.L.; Sanchez-Puerta, M.V. Towards a comprehensive picture of C-to-U RNA editing sites in angiosperm mitochondria. Plant Mol. Biol. 2018, 97, 215–231. [Google Scholar] [CrossRef] [PubMed]
  41. Gott, J.M.; Emeson, R.B. Functions and mechanisms of RNA editing. Annu. Rev. Genet. 2000, 34, 499–531. [Google Scholar] [CrossRef] [PubMed]
  42. Qu, Y.; Zhou, P.; Tong, C.; Bi, C.; Xu, L.a. Assembly and analysis of the Populus deltoides mitochondrial genome: The first report of a multicircular mitochondrial conformation for the genus Populus. J. For. Res. 2023, 34, 717–733. [Google Scholar] [CrossRef]
  43. Bi, C.; Lu, N.; Xu, Y.; He, C.; Lu, Z. Characterization and analysis of the mitochondrial genome of common bean (Phaseolus vulgaris) by comparative genomic approaches. Int. J. Mol. Sci. 2020, 21, 3778. [Google Scholar] [CrossRef]
  44. Chen, Y.; Zhang, S.; Wang, W.; Chen, X.; Zhao, Y.; Mo, Z.; Zhu, C. Chloroplast genome sequencing of Carya Illinoinensis cv. Xinxuan-4, a new pecan pollinated cultivar. Fruit Res. 2024, 4, e012. [Google Scholar] [CrossRef]
  45. Tsunewaki, K. Interorganellar DNA transfer in wheat: Dynamics and phylogenetic origin. Proc. JPN. Acad. Ser. B 2011, 87, 529–549. [Google Scholar] [CrossRef]
  46. Wei, L.; Liu, T.-J.; Hao, G.; Ge, X.-J.; Yan, H.-F. Comparative analyses of three complete Primula mitogenomes with insights into mitogenome size variation in Ericales. BMC Genom. 2022, 23, 770. [Google Scholar] [CrossRef]
  47. Shan, Y.; Li, J.; Zhang, X.; Yu, J. The complete mitochondrial genome of Amorphophallus albus and development of molecular markers for five Amorphophallus species based on mitochondrial DNA. Front. Plant Sci. 2023, 14, 1180417. [Google Scholar] [CrossRef] [PubMed]
  48. Simmonds, S.E.; Smith, J.F.; Davidson, C.; Buerki, S. Phylogenetics and comparative plastome genomics of two of the largest genera of angiosperms, Piper and Peperomia (Piperaceae). Mol. Phylogenetics Evol. 2021, 163, 107229. [Google Scholar] [CrossRef] [PubMed]
  49. Wang, X.-C.; Chen, H.; Yang, D.; Liu, C. Diversity of mitochondrial plastid DNAs (MTPTs) in seed plants. Mitochondrial DNA Part A 2018, 29, 635–642. [Google Scholar] [CrossRef] [PubMed]
  50. Krzywinski, M.; Schein, J.; Birol, I.; Connors, J.; Gascoyne, R.; Horsman, D.; Jones, S.J.; Marra, M.A. Circos: An information aesthetic for comparative genomics. Genome Res. 2009, 19, 1639–1645. [Google Scholar] [CrossRef] [PubMed]
  51. Alverson, A.J.; Wei, X.; Rice, D.W.; Stern, D.B.; Barry, K.; Palmer, J.D. Insights into the evolution of mitochondrial genome size from complete sequences of Citrullus lanatus and Cucurbita pepo (Cucurbitaceae). Mol. Biol. Evol. 2010, 27, 1436–1448. [Google Scholar] [CrossRef] [PubMed]
  52. Han, Y.; Feng, Y.-L.; Wang, J.; Zhu, S.-S.; Jin, X.-J.; Wu, Z.-Q.; Zhang, Y.-H. Comprehensive Analysis of the Complete Mitochondrial Genome of Rehmannia chingii: An Autotrophic Species in the Orobanchaceae Family. Genes 2024, 15, 98. [Google Scholar] [CrossRef] [PubMed]
  53. Duminil, J.; Besnard, G. Utility of the mitochondrial genome in plant taxonomic studies. Mol. Plant Taxon. Methods Protoc. 2021, 2222, 107–118. [Google Scholar]
  54. Wang, J.; Kan, S.; Liao, X.; Zhou, J.; Tembrock, L.R.; Daniell, H.; Jin, S.; Wu, Z. Plant organellar genomes: Much done, much more to do. Trends Plant Sci. 2024. [Google Scholar] [CrossRef]
Figure 1. The D. loddigesii mitogenome map consists of 17 circular chromosomes.
Figure 1. The D. loddigesii mitogenome map consists of 17 circular chromosomes.
Genes 15 00834 g001
Figure 2. Repeated sequence distribution in the D. loddigesii mitogenome. The outermost circle was the SSRs, followed by tandem repeat sequences, and the innermost was the dispersed repeat sequences.
Figure 2. Repeated sequence distribution in the D. loddigesii mitogenome. The outermost circle was the SSRs, followed by tandem repeat sequences, and the innermost was the dispersed repeat sequences.
Genes 15 00834 g002
Figure 3. RSCU in the D. loddigesii mitogenome. The x-axis represents the different kinds of amino acids. The y-axis represents the value of RSCU.
Figure 3. RSCU in the D. loddigesii mitogenome. The x-axis represents the different kinds of amino acids. The y-axis represents the value of RSCU.
Genes 15 00834 g003
Figure 4. Distribution of RNA-editing sites in PCGs of the D. loddigesii mitogenome.
Figure 4. Distribution of RNA-editing sites in PCGs of the D. loddigesii mitogenome.
Genes 15 00834 g004
Figure 5. Homologous fragments were distributed between mitochondria and chloroplast in D. loddigesii.
Figure 5. Homologous fragments were distributed between mitochondria and chloroplast in D. loddigesii.
Genes 15 00834 g005
Figure 6. Dot plot graphs show similar sequences between mitogenomes primarily in D. loddigesii and related species. The red line in the box is a forward comparison, while the blue line is a reverse complementary comparison.
Figure 6. Dot plot graphs show similar sequences between mitogenomes primarily in D. loddigesii and related species. The red line in the box is a forward comparison, while the blue line is a reverse complementary comparison.
Genes 15 00834 g006
Figure 7. Collinearity plots of the mitogenomes of D. loddigesii and related species. The boxes in each row represent the mitogenomes, and the lines in the middle represent homologous regions.
Figure 7. Collinearity plots of the mitogenomes of D. loddigesii and related species. The boxes in each row represent the mitogenomes, and the lines in the middle represent homologous regions.
Genes 15 00834 g007
Figure 8. The phylogenetic relationships of D. loddigesii and other 15 species based on conserved mitochondrial genes.
Figure 8. The phylogenetic relationships of D. loddigesii and other 15 species based on conserved mitochondrial genes.
Genes 15 00834 g008
Table 1. The information of the D. loddigesii mitogenome.
Table 1. The information of the D. loddigesii mitogenome.
IDAccession NumberLength (bp)GC (%)
Circular 1PP82917556,78144.42
Circular 2PP82917653,03043.36
Circular 3PP82917743,57141.19
Circular 4PP82917840,35344.24
Circular 5PP82917937,99643.02
Circular 6PP82918034,37142.63
Circular 7PP82918129,73043.32
Circular 8PP82918228,09643.44
Circular 9PP82918325,27244.40
Circular 10PP82918424,17543.87
Circular 11PP82918523,57745.93
Circular 12PP82918622,88940.28
Circular 13PP82918721,40745.55
Circular 14PP82918819,47145.01
Circular 15PP82918919,12838.27
Circular 16PP82919017,18644.82
Circular 17PP82919116,32345.08
Total-513,35643.41
Table 2. Gene composition in the D. loddigesii mitogenome.
Table 2. Gene composition in the D. loddigesii mitogenome.
Group of GenesName of Genes
ATP synthaseatp1, atp4, atp6, atp8, atp9
Cytochrome c biogenesisccmB, ccmC, ccmFc *, ccmFn
Ubiquinol cytochrome c reductasecob
Cytochrome c oxidasecox1, cox2 **, cox3
MaturasesmatR
Transport membrane proteinmttB
NADH dehydrogenasenad1 ****, nad2 ****, nad3, nad4 ***, nad4L, nad5 ****, nad6, nad7 ****, nad9
Large subunit of ribosomerpl5
Small subunit of ribosome rps10 *, rps12, rps13, rps14, rps7
Succinate dehydrogenase sdh4
Ribosomal RNAsrrn18, rrn26, rrn5
Transfer RNAstrnA-TGC *, trnC-GCA(2), trnD-GTC, trnE-TTC(2), trnF-GAA(2), trnG-GCC, trnI-TAT *, trnK-TTT, trnL-CAA, trnL-TAG, trnM-CAT(4), trnN-GTT(2), trnP-TGG, trnQ-TTG, trnR-ACG, trnS-GCT(2), trnS-GGA, trnT-GGT, trnT-TGT, trnV-GAC, trnW-CCA, trnY-GTA(2)
Notes: * one intron, ** two intron, *** three intron, **** four intron; Gene (2): Number of copies of multi-copy genes.
Table 3. Prediction of RNA-editing sites in the D. loddigesii mitogenome.
Table 3. Prediction of RNA-editing sites in the D. loddigesii mitogenome.
TypeRNA EditingNumberPercentage
Hydrophilic–hydrophilicCAC (H) => TAC (Y)8
CAT (H) => TAT (Y)18
CGC (R) => TGC (C)12
CGT (R) => TGT (C)32
Total7013.01%
Hydrophilic–hydrophobicACA (T) => ATA (I)5
ACG (T) => ATG (M)8
ACT (T) => ATT (I)4
CGG (R) => TGG (W)34
TCA (S) => TTA (L)77
TCC (S) => TTC (F)35
TCG (S) => TTG (L)44
TCT (S) => TTT (F)55
Total26248.70%
Hydrophilic–stopCGA (R) => TGA (X)2
Total20.37%
Hydrophobic–hydrophilicCCA (P) => TCA (S)8
CCC (P) => TCC (S)14
CCG (P) => TCG (S)6
CCT (P) => TCT (S)20
Total488.92%
Hydrophobic–hydrophobicCCA (P) => CTA (L)46
CCC (P) => CTC (L)8
CCC (P) => TTC (F)6
CCG (P) => CTG (L)27
CCT (P) => CTT (L)28
CCT (P) => TTT (F)14
CTC (L) => TTC (F)6
CTT (L) => TTT (F)12
GCA (A) => GTA (V)1
GCC (A) => GTC (V)1
GCG (A) => GTG (V)4
GCT (A) => GTT (V)3
Total15629.00%
All538100%
Table 4. Fragments transferred from chloroplast to mitochondria in D. loddigesii.
Table 4. Fragments transferred from chloroplast to mitochondria in D. loddigesii.
FragmentsAlignment Length (bp)Identity (%)CP StartCP EndMt StartMt EndGenes
1859599.16289,28797,86951,67243,104trnL-CAA
2859599.162138,714147,29643,10451,672trnL-CAA
3608099.266125,537131,59025,99719,973trnR-ACG, trnN-GUU
4500999.406104,993109,98319,97324,944trnR-ACG, trnN-GUU
5385597.58898,032101,87043,11739,293trnV-GAC
6385597.588134,713138,55139,29343,117trnV-GAC
789297.534131,912132,79519,98319,101trnA-UGC
889297.534103,788104,67119,10119,983trnA-UGC
956491.844111,119111,68223,52522,986trnL-UAG
10412491.84442,52046,61914,03218,149trnS-GGA, trnT-UGU
11133298.83636,28937,62081099435trnG-GCC, trnM-CAU
1252695.62731,81132,33664185908trnT-GGU
1343897.2631,38131,81071436706trnE-UUC, trnY-GUA
1439379.89847,96648,3311368trnF-GAA (partical: 72.60%)
1572885.714149,723150,41329,18028,493trnM-CAU
1672885.71486,17086,86028,49329,180trnM-CAU
1746684.33565,20665,66649315365trnW-CCA, trnP-UGG
1888774.183101,742102,60519,63618,778rrn18 (partical: 43.25%)
1988774.183133,978134,84118,77819,636rrn18 (partical: 43.25%)
2041979.47548,00948,39654015794trnF-GAA
2132990.2746532684736503977trnQ-UUG
2264982.8977774838611,71011,096trnS-GCU
232988.23545,07145,09911,43811,466trnS-GCU (partical: 32.95%)
248396.386126,909126,99128732791trnN-GUU
258396.386109,592109,67427912873trnN-GUU
269785.567105,841105,93727,25627,160rrn26 (partical: 2.83%)
279785.567130,646130,74227,16027,256rrn26 (partical: 2.83%)
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Tong, W.; Yu, D.; Zhu, X.; Le, Z.; Chen, H.; Hu, F.; Wu, S. The Whole Mitochondrial Genome Sequence of Dendrobium loddigesii Rolfe, an Endangered Orchid Species in China, Reveals a Complex Multi-Chromosome Structure. Genes 2024, 15, 834. https://doi.org/10.3390/genes15070834

AMA Style

Tong W, Yu D, Zhu X, Le Z, Chen H, Hu F, Wu S. The Whole Mitochondrial Genome Sequence of Dendrobium loddigesii Rolfe, an Endangered Orchid Species in China, Reveals a Complex Multi-Chromosome Structure. Genes. 2024; 15(7):834. https://doi.org/10.3390/genes15070834

Chicago/Turabian Style

Tong, Wenjun, Dandan Yu, Xiaojing Zhu, Zhifang Le, Hui Chen, Feilong Hu, and Shengmin Wu. 2024. "The Whole Mitochondrial Genome Sequence of Dendrobium loddigesii Rolfe, an Endangered Orchid Species in China, Reveals a Complex Multi-Chromosome Structure" Genes 15, no. 7: 834. https://doi.org/10.3390/genes15070834

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop