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Bacillus thuringiensis (Bt) is efficient, strongly specific, and avirulent to humans, making it one of the most popular biopesticides in the world. Bt LLP29 is a mosquitocidal strain that was first isolated from Magnolia denudata. To understand its molecular mechanism against mosquitoes, the genome of Bt LLP29 was sequenced and annotated in this study. The LLP29 genome was found to have a total length of 5.99 Mb, with an average G + C content of 35.21%. A total of 6107 coding sequences were also detected, together with 42 rRNAs and 124 tRNAs and 135 other RNAs. With the help of annotation databases, including GO, COG, KEGG, Nr and Swiss-Prot, most unigene functions were identified. At the same time, a collinear analysis was performed on the genome of LLP29. There were also some virulence genes detected, including cry, chitinase, zwittermicin and vip.
- Klíčová slova
- Bacillus thuringiensis, Genome sequencing, LLP29, Mosquito, Toxicity,
- MeSH
- anotace sekvence MeSH
- Bacillus thuringiensis genetika MeSH
- bakteriální proteiny genetika MeSH
- faktory virulence genetika MeSH
- genom bakteriální genetika MeSH
- sekvenční analýza MeSH
- sekvenování celého genomu * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- bakteriální proteiny MeSH
- faktory virulence MeSH
BACKGROUND AND AIMS: Cardamine occulta (Brassicaceae) is an octoploid weedy species (2n = 8x = 64) originated in Eastern Asia. It has been introduced to other continents including Europe and considered to be an invasive species. Despite its wide distribution, the polyploid origin of C. occulta remained unexplored. The feasibility of comparative chromosome painting (CCP) in crucifers allowed us to elucidate the origin and genome evolution in Cardamine species. We aimed to investigate the genome structure of C. occulta in comparison with its tetraploid (2n = 4x = 32, C. kokaiensis and C. scutata) and octoploid (2n = 8x = 64, C. dentipetala) relatives. METHODS: Genomic in situ hybridization (GISH) and large-scale CCP were applied to uncover the parental genomes and chromosome composition of the investigated Cardamine species. KEY RESULTS: All investigated species descended from a common ancestral Cardamine genome (n = 8), structurally resembling the Ancestral Crucifer Karyotype (n = 8), but differentiated by a translocation between chromosomes AK6 and AK8. Allotetraploid C. scutata originated by hybridization between two diploid species, C. parviflora and C. amara (2n = 2x = 16). By contrast, C. kokaiensis has an autotetraploid origin from a parental genome related to C. parviflora. Interestingly, octoploid C. occulta probably originated through hybridization between the tetraploids C. scutata and C. kokaiensis. The octoploid genome of C. dentipetala probably originated from C. scutata via autopolyploidization. Except for five species-specific centromere repositionings and one pericentric inversion post-dating the polyploidization events, the parental subgenomes remained stable in the tetra- and octoploids. CONCLUSIONS: Comparative genome structure, origin and evolutionary history was reconstructed in C. occulta and related species. For the first time, whole-genome cytogenomic maps were established for octoploid plants. Post-polyploid evolution in Asian Cardamine polyploids has not been associated with descending dysploidy and intergenomic rearrangements. The combination of different parental (sub)genomes adapted to distinct habitats provides an evolutionary advantage to newly formed polyploids by occupying new ecological niches.
- Klíčová slova
- Allopolyploidy, Asian Cardamine, Brassicaceae, GISH (genomic in situ hybridization), autopolyploidy, centromere repositioning, chromosome rearrangements, comparative chromosome painting, diploidization, genome collinearity, hybridization, invasive species,
- MeSH
- Brassicaceae * MeSH
- Cardamine * MeSH
- genom rostlinný MeSH
- lidé MeSH
- polyploidie MeSH
- zavlečené druhy MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Dálný východ MeSH
- Evropa MeSH
Hexaploid camelina (Camelina sativa; 2n = 6x = 40) is an important oilseed crop closely related to Arabidopsis. Compared to other polyploid crops, the origin of the three camelina subgenomes has begun to be unveiled only recently. While phylogenomic studies identified the diploid C. hispida (2n = 2x = 14) as the paternal genome of C. sativa, the maternal donor genome remained unknown. Because the chromosomes assigned to a putative maternal genome resembled those of diploid C. neglecta (2n = 12), a tetraploid C. neglecta-like genome (2n = 4x = 26) was hypothesized to be the likely maternal ancestor of the hexaploid crop. Here we report the chromosome-level structure of the predicted tetraploid Camelina genome identified among genotypes previously classified together as C. microcarpa and referred to here as C. intermedia. Detailed cytogenomic analysis of the tetraploid genome revealed high collinearity with two maternally inherited subgenomes of the hexaploid C. sativa. The identification of the missing donor tetraploid genome provides new insights into the reticulate evolutionary history of the Camelina polyploid complex and allows us to postulate a comprehensive evolutionary model for the genus. The herein elucidated origin of the C. sativa genome opens the door for subsequent genome modifications and resynthesis of the allohexaploid camelina genome.
- Klíčová slova
- Camelina, Brassicaceae, allopolyploidy, chromosome rearrangements, false flax, genome evolution, hybridization,
- MeSH
- Arabidopsis * genetika MeSH
- Brassicaceae * genetika MeSH
- diploidie MeSH
- genom rostlinný genetika MeSH
- polyploidie MeSH
- tetraploidie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Horseradish (Armoracia rusticana) and watercress (Nasturtium officinale) are economically important cruciferous vegetable species with limited genomic resources. We used comparative chromosome painting to identify the extent of chromosomal collinearity between horseradish and watercress, and to reconstruct the origin and evolution of the two tetraploid genomes (2n = 4x = 32). Our results show that horseradish and watercress genomes originated from a common ancestral (n = 8) genome, structurally resembling the Ancestral Crucifer Karyotype (n = 8), which, however, contained two unique translocation chromosomes (AK6/8 and AK8/6). Except for a 2.4-Mb unequal chromosome translocation in watercress, both genomes are structurally identical. The structural similarity of the two parental subgenomes might suggest an autotetraploid origin of horseradish and watercress genomes. The subgenome stasis, apart from the single-chromosome translocation, indicates that homeologous recombination played a limited role in postpolyploid evolution in both tetraploid genomes. The octoploid genome of one-rowed watercress (N. microphyllum, 2n = 8x = 64), structurally mirroring the tetraploid horseradish and watercress genomes, originated via autopolyploidization from the immediate tetraploid predecessor of watercress or hybridization between this and another now-extinct tetraploid Nasturtium species. These comparative cytogenomic maps in horseradish and watercress represent a first stepping stone for future whole-genome sequencing efforts and genetic improvement of both crop species.
Helicobacter pylori (H. pylori) is a Gram-negative pathogen as a carcinogen of the class Ι, with unique genetic diversity and wide geographic differences. The high incidence of gastric cancer in East Asia may be related to the bacterial genotype. It is of great significance that the genome of H. pylori in East Asia is widely collected. Therefore, we combined two sequencing technologies (PacBio and Illumina HiSeq 4000) and multiple databases to sequence and annotate the whole genome of H. pylori GZ7 isolated from a gastric cancer patient in Guizhou, China. Furthermore, this sequence was further compared with the genome sequence of 23 H. pylori strains isolated from different regions through collinearity comparison, specific gene analysis, phylogenetic tree construction, etc. The results showed that the genome of H. pylori GZ7 consists of 1,579,995 bp circle chromosomes with a GC content of 39.51%. This chromosome has 1,572 coding sequences, three antibiotic resistance genes, five prophages, and 198 virulence genes. The comparative genome analyses showed that H. pylori GZ7 has 53 specific genes compared to the other 23 strains. Most of these specific genes have not been annotated and characterized until now, whose research may provide insights into the biological activities of this strain. H. pylori GZ7 has the closest genetic relationship with H. pylori F30, and the farthest genetic relationship with H. pylori ELS37, which indicates that H. pylori genomes have geographical differences. This information may provide a molecular basis and guidance for constructing diagnostic methods for H. pylori and researching subsequent experiments.
- Klíčová slova
- Comparative genomics, Gene annotation, Helicobacter pylori, Whole-genome sequencing,
- MeSH
- fylogeneze MeSH
- genom bakteriální MeSH
- Helicobacter pylori * MeSH
- infekce vyvolané Helicobacter pylori * mikrobiologie MeSH
- lidé MeSH
- nádory žaludku * genetika mikrobiologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The origin of Cardamine flexuosa (Wavy Bittercress) has been a conundrum for more than six decades. Here we identify its parental species, analyse its genome structure in comparison to parental genomes and describe intergenomic structural variations in C. flexuosa. Genomic in situ hybridization (GISH) and comparative chromosome painting (CCP) uncovered the parental genomes and the chromosome composition of C. flexuosa and its presumed diploid progenitors. Cardamine flexuosa is an allotetraploid (2n = 4x = 32), originating from two diploid species, Cardamine amara and Cardamine hirsuta (2n = 2x = 16). The two parental species display almost perfectly conserved chromosomal collinearity for seven out of the eight chromosomes. A 13 Mb pericentric inversion distinguishes chromosome CA1 from CH1. A comparative cytomolecular map was established for C. flexuosa by CCP/GISH. Whereas conserved chromosome collinearity between the C. amara and C. hirsuta subgenomes might have promoted intergenomic rearrangements through homeologous recombination, only one reciprocal translocation between two homeologues has occurred since the origin of C. flexuosa. The genome of C. flexuosa demonstrates that allopolyploids can maintain remarkably stable subgenomes over 10(4) -10(5) yr throughout a wide distribution range. By contrast, the rRNA genes underwent genome-specific elimination towards a diploid-like number of loci.
- Klíčová slova
- Brassicaceae, Cardamine flexuosa (Wavy Bittercress), GISH (genomic in situ hybridization), chromosome painting, genome collinearity, intergenome translocation, polyploidy,
- MeSH
- Cardamine genetika MeSH
- chromozomy rostlin genetika MeSH
- délka genomu genetika MeSH
- diploidie MeSH
- druhová specificita MeSH
- genetické lokusy genetika MeSH
- genom rostlinný genetika MeSH
- hybridizace in situ MeSH
- karyotypizace MeSH
- konzervovaná sekvence * MeSH
- malování chromozomů MeSH
- polyploidie * MeSH
- ribozomální DNA genetika MeSH
- translokace genetická MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- ribozomální DNA MeSH
Centromere position may change despite conserved chromosomal collinearity. Centromere repositioning and evolutionary new centromeres (ENCs) were frequently encountered during vertebrate genome evolution but only rarely observed in plants. The largest crucifer tribe, Arabideae (∼550 species; Brassicaceae, the mustard family), diversified into several well-defined subclades in the virtual absence of chromosome number variation. Bacterial artificial chromosome-based comparative chromosome painting uncovered a constancy of genome structures among 10 analyzed genomes representing seven Arabideae subclades classified as four genera: Arabis, Aubrieta, Draba, and Pseudoturritis Interestingly, the intra-tribal diversification was marked by a high frequency of ENCs on five of the eight homoeologous chromosomes in the crown-group genera, but not in the most ancestral Pseudoturritis genome. From the 32 documented ENCs, at least 26 originated independently, including 4 ENCs recurrently formed at the same position in not closely related species. While chromosomal localization of ENCs does not reflect the phylogenetic position of the Arabideae subclades, centromere seeding was usually confined to long chromosome arms, transforming acrocentric chromosomes to (sub)metacentric chromosomes. Centromere repositioning is proposed as the key mechanism differentiating overall conserved homoeologous chromosomes across the crown-group Arabideae subclades. The evolutionary significance of centromere repositioning is discussed in the context of possible adaptive effects on recombination and epigenetic regulation of gene expression.
Barley (Hordeum vulgare L.) possesses a large and highly repetitive genome of 5.1 Gb that has hindered the development of a complete sequence. In 2012, the International Barley Sequencing Consortium released a resource integrating whole-genome shotgun sequences with a physical and genetic framework. However, because only 6278 bacterial artificial chromosome (BACs) in the physical map were sequenced, fine structure was limited. To gain access to the gene-containing portion of the barley genome at high resolution, we identified and sequenced 15 622 BACs representing the minimal tiling path of 72 052 physical-mapped gene-bearing BACs. This generated ~1.7 Gb of genomic sequence containing an estimated 2/3 of all Morex barley genes. Exploration of these sequenced BACs revealed that although distal ends of chromosomes contain most of the gene-enriched BACs and are characterized by high recombination rates, there are also gene-dense regions with suppressed recombination. We made use of published map-anchored sequence data from Aegilops tauschii to develop a synteny viewer between barley and the ancestor of the wheat D-genome. Except for some notable inversions, there is a high level of collinearity between the two species. The software HarvEST:Barley provides facile access to BAC sequences and their annotations, along with the barley-Ae. tauschii synteny viewer. These BAC sequences constitute a resource to improve the efficiency of marker development, map-based cloning, and comparative genomics in barley and related crops. Additional knowledge about regions of the barley genome that are gene-dense but low recombination is particularly relevant.
- Klíčová slova
- Aegilops tauschii, BAC sequencing, Barley, HarvEST:Barley, Hordeum vulgare L., centromere BACs, gene distribution, recombination frequency, synteny,
- MeSH
- genom rostlinný genetika MeSH
- ječmen (rod) genetika MeSH
- molekulární sekvence - údaje MeSH
- umělé bakteriální chromozomy genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Goatgrasses with U- and M-genomes are important sources of new alleles for wheat breeding to maintain yield and quality under extreme conditions. However, the introgression of beneficial traits from wild Aegilops species into wheat has been limited by poor knowledge of their genomes and scarcity of molecular tools. Here, we present the first linkage map of allotetraploid Aegilops biuncialis Vis., developed using 224 F2 individuals derived from a cross between MvGB382 and MvGB642 accessions. The map comprises 5663 DArTseq markers assigned to 15 linkage groups corresponding to 13 chromosomes. Chromosome 1Mb could not be constructed due to a lack of recombination caused by rearrangements in the MvGB382 accession. The genetic map spans 2518 cM with an average marker density of 2.79 cM. The skeleton map contains 920 segregating markers, divided between the Mb sub-genome (425 markers) and the Ub sub-genome (495 markers). Chromosomes of the Mb sub-genome, originating from Aegilops comosa Sm. in Sibth. et Sm., show well-preserved collinearity with Triticum aestivum L. chromosomes. In contrast, chromosomes of the Ub sub-genome, originating from Aegilops umbellulata Zhuk., exhibit a varying degree of collinearity, with 1Ub, 3Ub, and 5Ub retaining a substantial level of collinearity with Triticum aestivum, while 2Ub, 4Ub, 6Ub, and 7Ub show significant rearrangements. A quantitative trait locus affecting fertility was identified near the centromere on the long arm of chromosome 3Mb, explaining 23.5% of the variance. The genome structure of Aegilops biuncialis, highlighted by the genetic map, provides insights into the speciation within the species and will support alien gene transfer into wheat.
Eustigmatophyceae (Ochrophyta, Stramenopiles) is a small algal group with species of the genus Nannochloropsis being its best studied representatives. Nuclear and organellar genomes have been recently sequenced for several Nannochloropsis spp., but phylogenetically wider genomic studies are missing for eustigmatophytes. We sequenced mitochondrial genomes (mitogenomes) of three species representing most major eustigmatophyte lineages, Monodopsis sp. MarTras21, Vischeria sp. CAUP Q 202 and Trachydiscus minutus, and carried out their comparative analysis in the context of available data from Nannochloropsis and other stramenopiles, revealing a number of noticeable findings. First, mitogenomes of most eustigmatophytes are highly collinear and similar in the gene content, but extensive rearrangements and loss of three otherwise ubiquitous genes happened in the Vischeria lineage; this correlates with an accelerated evolution of mitochondrial gene sequences in this lineage. Second, eustigmatophytes appear to be the only ochrophyte group with the Atp1 protein encoded by the mitogenome. Third, eustigmatophyte mitogenomes uniquely share a truncated nad11 gene encoding only the C-terminal part of the Nad11 protein, while the N-terminal part is encoded by a separate gene in the nuclear genome. Fourth, UGA as a termination codon and the cognate release factor mRF2 were lost from mitochondria independently by the Nannochloropsis and T. minutus lineages. Finally, the rps3 gene in the mitogenome of Vischeria sp. is interrupted by the UAG codon, but the genome includes a gene for an unusual tRNA with an extended anticodon loop that we speculate may serve as a suppressor tRNA to properly decode the rps3 gene.
- Klíčová slova
- Eustigmatophyceae, Stramenopiles, evolution, phylogenomics, split genes, suppressor tRNA,
- MeSH
- fylogeneze * MeSH
- genom mitochondriální MeSH
- genomika MeSH
- Heterokontophyta genetika MeSH
- molekulární evoluce * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH