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Structural features of two major nucleolar organizer regions (NORs), Nor-B1 and Nor-B2, and chromosome-specific rRNA gene expression in wheat
- Source :
- Plant Journal, Plant Journal, Wiley, 2018, 96 (6), pp.1148-1159. ⟨10.1111/tpj.14094⟩, SC30201812190009, NARO成果DBd, Plant Journal 6 (96), 1148-1159. (2018), Plant Journal, 2018, 96 (6), pp.1148-1159. ⟨10.1111/tpj.14094⟩
- Publication Year :
- 2018
- Publisher :
- HAL CCSD, 2018.
-
Abstract
- The reference genome sequence of wheat 'Chinese Spring' (CS) is now available (IWGSC RefSeq v1.0), but the core sequences defining the nucleolar organizer regions (NORs) have not been characterized. We estimated that the total copy number of the rDNA units in the wheat genome is 11 160, of which 30.5%, 60.9% and 8.6% are located on Nor-B1 (1B), Nor-B2 (6B) and other NORs, respectively. The total length of the NORs is estimated to be 100 Mb, corresponding to approximately 10% of the unassembled portion of the genome not represented in RefSeq v1.0. Four subtypes (S1-S4) of the rDNA units were identified based on differences within the 3' external transcribed spacer regions in Nor-B1 and Nor-B2, and quantitative PCR indicated locus-specific variation in rDNA subtype contents. Expression analyses of rDNA subtypes revealed that S1 was predominantly expressed and S2 weakly expressed, in contrast to the relative abundance of rDNA subtypes in the wheat genome. These results suggest a regulation mechanism of differential rDNA expression based on sequence differences. S3 expression increased in the ditelosomic lines Dt1BL and Dt6BL, suggesting that S3 is subjected to chromosome-mediated silencing. Structural differences were detected in the regions surrounding the NOR among homoeologous chromosomes of groups 1 and 6. The adjacent regions distal to the major NORs were expanded compared with their homoeologous counterparts, and the gene density of these expanded regions was relatively low. We provide evidence that these regions are likely to be important for autoregulation of the associated major NORs as well as silencing of minor NORs.
- Subjects :
- 0106 biological sciences
0301 basic medicine
Triticum aestivum L
rDNA unit subtypes
DNA Copy Number Variations
gene expression
nucleolar dominance
nucleolar organizer region
sequence structure
Plant Science
Biology
Genes, Plant
Polymerase Chain Reaction
01 natural sciences
Genome
Chromosomes, Plant
ribosomal dna
03 medical and health sciences
blé
Gene Expression Regulation, Plant
Gene density
wheat
Gene expression
Genetics
RefSeq
[SDV.BV]Life Sciences [q-bio]/Vegetal Biology
In Situ Hybridization, Fluorescence
Triticum
2. Zero hunger
Vegetal Biology
Chromosome
Cell Biology
Ribosomal RNA
adn ribosomique
External transcribed spacer
structure génétique
030104 developmental biology
Genetic Loci
RNA, Plant
RNA, Ribosomal
nucleolus organizer region
Nucleolus organizer region
Genome, Plant
Biologie végétale
010606 plant biology & botany
expression des gènes
organisateur nucléolaire
Subjects
Details
- Language :
- English
- ISSN :
- 09607412 and 1365313X
- Database :
- OpenAIRE
- Journal :
- Plant Journal, Plant Journal, Wiley, 2018, 96 (6), pp.1148-1159. ⟨10.1111/tpj.14094⟩, SC30201812190009, NARO成果DBd, Plant Journal 6 (96), 1148-1159. (2018), Plant Journal, 2018, 96 (6), pp.1148-1159. ⟨10.1111/tpj.14094⟩
- Accession number :
- edsair.doi.dedup.....852a3c31b49d00e6ff129b569ca6b306