Insight into the Organization of the B10v3 Cucumber Genome by Integration of Biological and Bioinformatic Data

The availability of a well-organized and annotated reference genome is essential for genome research and the analysis of re-sequencing approaches. The B10v3 cucumber (Cucumis sativus L.) reference genome has been sequenced and assembled into 8035 contigs, a small fraction of which have been mapped to individual chromosomes. Currently, bioinformatics methods based on comparative homology have made it possible to re-order the sequenced contigs by mapping them to the reference genomes. The B10v3 genome (North-European, Borszczagowski line) was rearranged against the genomes of cucumber 9930 (‘Chinese Long’ line) and Gy14 (North American line). Furthermore, a better insight into the organization of the B10v3 genome was obtained by integrating the data available in the literature on the assignment of contigs to chromosomes in the B10v3 genome with the results of the bioinformatic analysis. The combination of information on the markers used in the assembly of the B10v3 genome and the results of FISH and DArT-seq experiments confirmed the reliability of the in silico assignment. Approximately 98% of the protein-coding genes within the chromosomes were assigned and a significant proportion of the repetitive fragments in the sequenced B10v3 genome were identified using the RagTag programme. In addition, BLAST analyses provided comparative information between the B10v3 genome and the 9930 and Gy14 data sets. This revealed both similarities and differences in the functional proteins found between the coding sequences region in the genomes. This study contributes to better knowledge and understanding of cucumber genome line B10v3

Molecular insight into somaclonal variation phenomena from transcriptome profiling of cucumber (Cucumis sativus L.) lines

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Effect of Transgenesis on mRNA and miRNA Profiles in Cucumber Fruits Expressing Thaumatin II

Transgenic plants are commonly used in breeding programs because of the various features that can be introduced. However, unintended effects caused by genetic transformation are still a topic of concern. This makes research on the nutritional safety of transgenic crop plants extremely interesting. Cucumber (Cucumis sativus L.) is a crop that is grown worldwide. The aim of this study was to identify and characterize differentially expressed genes and regulatory miRNAs in transgenic cucumber fruits that contain the thaumatin II gene, which encodes the sweet-tasting protein thaumatin II, by NGS sequencing. We compared the fruit transcriptomes and miRNomes of three transgenic cucumber lines with wild-type cucumber. In total, we found 47 differentially expressed genes between control and all three transgenic lines. We performed the bioinformatic functional analysis and gene ontology classification. We also identified 12 differentially regulated miRNAs, from which three can influence the two targets (assigned as DEGs) in one of the studied transgenic lines (line 224). We found that the transformation of cucumber with thaumatin II and expression of the transgene had minimal impact on gene expression and epigenetic regulation by miRNA, in the cucumber fruits

Characterization of Lebanese Germplasm of Snake Melon (Cucumis melo subsp. melo var. flexuosus) Using Morphological Traits and SSR Markers

Snake melon (Cucumis melo subsp. melo L. var. flexuosus (L.) Naudin) is an ancient and traditional crop in the Mediterranean region. Nevertheless, there has been poor interest in assessing snake melon germplasm where its genetic resources have not been surveyed before despite their potential in adaptation to environmental changes. In this study, we assess the genetic diversity of snake melon landraces collected from different Lebanese regions at both morphological and molecular levels. Morphological characterization using a set of 18 descriptors revealed an important phenotypic variability among the landraces studied. Principle component analysis indicated that fruit hair and its consistency, fruit size, and skin color pattern were good criteria for discriminating among landraces. Based on the scatter plot diagram, landraces of snake melon formed five different groups with one being defined as typical var. flexuosus. Ten simple sequence repeat (SSR) markers were used for the molecular characterization. Fifty-six different alleles were detected, with an average of 5.6 alleles per locus. Polymorphism information content of SSR markers ranged from 0.06 to 0.84 (average 0.38). Cluster analysis based on molecular markers showed high genetic diversity and divided the landraces into five distinct genetic groups, confirming thereby the morphological variability. Findings of this study indicate a significant diversity for the Lebanese snake melon germplasm that must be further conserved and considered in improvement programs of this ancient crop

Erratum to: Abundance and diversity of the faecal resistome in slaughter pigs and broilers in nine European countries (Nature Microbiology, (2018), 3, 8, (898-908), 10.1038/s41564-018-0192-9)

In the version of this Article originally published, the surname of author Oksana Lukjancenko was spelt incorrectly as ‘Lukjacenko’. This has now been corrected

Abundance and diversity of the faecal resistome in slaughter pigs and broilers in nine European countries

Antimicrobial resistance (AMR) in bacteria and associated human morbidity and mortality is increasing. The use of antimicrobials in livestock selects for AMR that can subsequently be transferred to humans. This flow of AMR between reservoirs demands surveillance in livestock and in humans. We quantified and characterized the acquired resistance gene pools (resistomes) of 181 pig and 178 poultry farms from nine European countries, sequencing more than 5,000 Gb of DNA using shotgun metagenomics. We quantified acquired AMR using the ResFinder database and a second database constructed for this study, consisting of AMR genes identified through screening environmental DNA. The pig and poultry resistomes were very different in abundance and composition. There was a significant country effect on the resistomes, more so in pigs than in poultry. We found higher AMR loads in pigs, whereas poultry resistomes were more diverse. We detected several recently described, critical AMR genes, including mcr-1 and optrA, the abundance of which differed both between host species and between countries. We found that the total acquired AMR level was associated with the overall country-specific antimicrobial usage in livestock and that countries with comparable usage patterns had similar resistomes. However, functionally determined AMR genes were not associated with total drug use

Author Correction: Abundance and diversity of the faecal resistome in slaughter pigs and broilers in nine European countries

In the version of this Article originally published, the surname of author Oksana Lukjancenko was spelt incorrectly as ‘Lukjacenko’. This has now been corrected.</p

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