An advanced reference genome of Trifolium subterraneum L. reveals genes related to agronomic performance

Parwinder Kaur, Philipp E. Bayer, Zbyněk Milec, Jan Vrána, Yuxuan Yuan, Rudi Appels, David Edwards, Jacqueline Batley, Phillip Nichols, William Erskine, Jaroslav Doležel

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Summary: Subterranean clover is an important annual forage legume, whose diploidy and inbreeding nature make it an ideal model for genomic analysis in Trifolium. We reported a draft genome assembly of the subterranean clover TSUd_r1.1. Here we evaluate genome mapping on nanochannel arrays and generation of a transcriptome atlas across tissues to advance the assembly and gene annotation. Using a BioNano-based assembly spanning 512 Mb (93% genome coverage), we validated the draft assembly, anchored unplaced contigs and resolved misassemblies. Multiple contigs (264) from the draft assembly coalesced into 97 super-scaffolds (43% of genome). Sequences longer than >1 Mb increased from 40 to 189 Mb giving 1.4-fold increase in N50 with total genome in pseudomolecules improved from 73 to 80%. The advanced assembly was re-annotated using transcriptome atlas data to contain 31 272 protein-coding genes capturing >96% of the gene content. Functional characterization and GO enrichment confirmed gene expression for response to water deprivation, flavonoid biosynthesis and embryo development ending in seed dormancy, reflecting adaptation to the harsh Mediterranean environment. Comparative analyses across Papilionoideae identified 24 893 Trifolium-specific and 6325 subterranean-clover-specific genes that could be mined further for traits such as geocarpy and grazing tolerance. Eight key traits, including persistence, improved livestock health by isoflavonoid production in addition to important agro-morphological traits, were fine-mapped on the high-density SNP linkage map anchored to the assembly. This new genomic information is crucial to identify loci governing traits allowing marker-assisted breeding, comparative mapping and identification of tissue-specific gene promoters for biotechnological improvement of forage legumes.

Original languageEnglish
Pages (from-to)1034-1046
Number of pages13
JournalPlant Biotechnology Journal
Volume15
Issue number8
DOIs
Publication statusPublished - 12 Jul 2017

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Trifolium
Trifolium subterraneum
agronomic traits
Medicago
Genome
genome
Atlases
Transcriptome
Fabaceae
Genes
forage legumes
genes
transcriptome
Plant Dormancy
chromosome mapping
Water Deprivation
Molecular Sequence Annotation
Inbreeding
Chromosome Mapping
Livestock

Cite this

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title = "An advanced reference genome of Trifolium subterraneum L. reveals genes related to agronomic performance",
abstract = "Summary: Subterranean clover is an important annual forage legume, whose diploidy and inbreeding nature make it an ideal model for genomic analysis in Trifolium. We reported a draft genome assembly of the subterranean clover TSUd_r1.1. Here we evaluate genome mapping on nanochannel arrays and generation of a transcriptome atlas across tissues to advance the assembly and gene annotation. Using a BioNano-based assembly spanning 512 Mb (93{\%} genome coverage), we validated the draft assembly, anchored unplaced contigs and resolved misassemblies. Multiple contigs (264) from the draft assembly coalesced into 97 super-scaffolds (43{\%} of genome). Sequences longer than >1 Mb increased from 40 to 189 Mb giving 1.4-fold increase in N50 with total genome in pseudomolecules improved from 73 to 80{\%}. The advanced assembly was re-annotated using transcriptome atlas data to contain 31 272 protein-coding genes capturing >96{\%} of the gene content. Functional characterization and GO enrichment confirmed gene expression for response to water deprivation, flavonoid biosynthesis and embryo development ending in seed dormancy, reflecting adaptation to the harsh Mediterranean environment. Comparative analyses across Papilionoideae identified 24 893 Trifolium-specific and 6325 subterranean-clover-specific genes that could be mined further for traits such as geocarpy and grazing tolerance. Eight key traits, including persistence, improved livestock health by isoflavonoid production in addition to important agro-morphological traits, were fine-mapped on the high-density SNP linkage map anchored to the assembly. This new genomic information is crucial to identify loci governing traits allowing marker-assisted breeding, comparative mapping and identification of tissue-specific gene promoters for biotechnological improvement of forage legumes.",
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An advanced reference genome of Trifolium subterraneum L. reveals genes related to agronomic performance. / Kaur, Parwinder; Bayer, Philipp E.; Milec, Zbyněk; Vrána, Jan; Yuan, Yuxuan; Appels, Rudi; Edwards, David; Batley, Jacqueline; Nichols, Phillip; Erskine, William; Doležel, Jaroslav.

In: Plant Biotechnology Journal, Vol. 15, No. 8, 12.07.2017, p. 1034-1046.

Research output: Contribution to journalArticle

TY - JOUR

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AU - Kaur, Parwinder

AU - Bayer, Philipp E.

AU - Milec, Zbyněk

AU - Vrána, Jan

AU - Yuan, Yuxuan

AU - Appels, Rudi

AU - Edwards, David

AU - Batley, Jacqueline

AU - Nichols, Phillip

AU - Erskine, William

AU - Doležel, Jaroslav

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N2 - Summary: Subterranean clover is an important annual forage legume, whose diploidy and inbreeding nature make it an ideal model for genomic analysis in Trifolium. We reported a draft genome assembly of the subterranean clover TSUd_r1.1. Here we evaluate genome mapping on nanochannel arrays and generation of a transcriptome atlas across tissues to advance the assembly and gene annotation. Using a BioNano-based assembly spanning 512 Mb (93% genome coverage), we validated the draft assembly, anchored unplaced contigs and resolved misassemblies. Multiple contigs (264) from the draft assembly coalesced into 97 super-scaffolds (43% of genome). Sequences longer than >1 Mb increased from 40 to 189 Mb giving 1.4-fold increase in N50 with total genome in pseudomolecules improved from 73 to 80%. The advanced assembly was re-annotated using transcriptome atlas data to contain 31 272 protein-coding genes capturing >96% of the gene content. Functional characterization and GO enrichment confirmed gene expression for response to water deprivation, flavonoid biosynthesis and embryo development ending in seed dormancy, reflecting adaptation to the harsh Mediterranean environment. Comparative analyses across Papilionoideae identified 24 893 Trifolium-specific and 6325 subterranean-clover-specific genes that could be mined further for traits such as geocarpy and grazing tolerance. Eight key traits, including persistence, improved livestock health by isoflavonoid production in addition to important agro-morphological traits, were fine-mapped on the high-density SNP linkage map anchored to the assembly. This new genomic information is crucial to identify loci governing traits allowing marker-assisted breeding, comparative mapping and identification of tissue-specific gene promoters for biotechnological improvement of forage legumes.

AB - Summary: Subterranean clover is an important annual forage legume, whose diploidy and inbreeding nature make it an ideal model for genomic analysis in Trifolium. We reported a draft genome assembly of the subterranean clover TSUd_r1.1. Here we evaluate genome mapping on nanochannel arrays and generation of a transcriptome atlas across tissues to advance the assembly and gene annotation. Using a BioNano-based assembly spanning 512 Mb (93% genome coverage), we validated the draft assembly, anchored unplaced contigs and resolved misassemblies. Multiple contigs (264) from the draft assembly coalesced into 97 super-scaffolds (43% of genome). Sequences longer than >1 Mb increased from 40 to 189 Mb giving 1.4-fold increase in N50 with total genome in pseudomolecules improved from 73 to 80%. The advanced assembly was re-annotated using transcriptome atlas data to contain 31 272 protein-coding genes capturing >96% of the gene content. Functional characterization and GO enrichment confirmed gene expression for response to water deprivation, flavonoid biosynthesis and embryo development ending in seed dormancy, reflecting adaptation to the harsh Mediterranean environment. Comparative analyses across Papilionoideae identified 24 893 Trifolium-specific and 6325 subterranean-clover-specific genes that could be mined further for traits such as geocarpy and grazing tolerance. Eight key traits, including persistence, improved livestock health by isoflavonoid production in addition to important agro-morphological traits, were fine-mapped on the high-density SNP linkage map anchored to the assembly. This new genomic information is crucial to identify loci governing traits allowing marker-assisted breeding, comparative mapping and identification of tissue-specific gene promoters for biotechnological improvement of forage legumes.

KW - Advanced reference assembly

KW - BioNano

KW - Forage legumes

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KW - Legume comparative genomics

KW - Transcriptome

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