Dataset Information

The role of small RNAs in wide hybridisation and allopolyploidisation between Brassica rapa and Brassica nigra

ABSTRACT: An allopolyploid formation consists of the two processes of hybridisation and chromosome doubling. Hybridisation makes a different genome combined in the same cell, and genome “shock” and instability occur during this process, whereas chromosome doubling results in doubling and reconstructing the genome dosage. Recent studies have demonstrated that small RNAs, mainly siRNAs and miRNAs, play an important role in maintaining the genome reconstruction and stability. However, to date, little is known regarding the role of small RNAs during the process of wide hybridisation and chromosome doubling, which is essential to elucidate the mechanism of polyploidisation. Therefore, the genetic and DNA methylation alterations and changes in the siRNA and miRNA were assessed during the formation of an allodiploid (genome: AB) and its allotetraploid (genome: AABB) between Brassica rapa (♀) and Brassica nigra (♂) in the present study.The phenotypic analysis exhibited that the allotetraploid had high heterosis compared with their parents and the allodiploid. The methylation-sensitive amplification polymorphism (MSAP) analysis indicated that the proportion of changes in the methylation pattern of the allodiploid was significantly higher than that found in the allotetraploid, while the DNA methylation ratio was higher in the parents than the allodiploid and allotetraploid. The high-throughput sequencing results obtained for the small RNAs showed that the expression levels of miRNAs increased in the allodiploid and allotetraploid compared with the parents, and the expression levels of siRNAs increased and decreased compared with the parents B. rapa and B. nigra, respectively. Moreover, the percentages of miRNAs increased with an increase in the polyploidy levels, but the percentages of siRNAs and DNA methylation alterations decreased with an increase in the polyploidy levels. Furthermore, 320 known and 52 novel miRNAs were obtained from the parents in both the allodiploid and allotetraploid. However, quantitative real-time polymerase chain reaction (qRT PCR) analysis showed that the expression levels of the targets genes were negatively corrected with the expressed miRNAs.The study showed that siRNAs and DNA methylation play an important role in maintaining the genome stability in the formation of an allotetraploid. The miRNAs regulate gene expression and induce the phenotype variation, which may play an important role in the occurrence of heterosis in the allotetraploid. The findings of this study may provide new information for elucidating that the allotetraploids have a growth advantage over the parents and the allodiploids.

ORGANISM(S): Brassica rapa Brassica nigra Brassica rapa x Brassica nigra

PROVIDER: GSE61872 | GEO | 2014/09/30

SECONDARY ACCESSION(S): PRJNA262578

REPOSITORIES: GEO

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Project description:An allopolyploid formation consists of the two processes of hybridisation and chromosome doubling. Hybridisation makes a different genome combined in the same cell, and genome M-bM-^@M-^\shockM-bM-^@M-^] and instability occur during this process, whereas chromosome doubling results in doubling and reconstructing the genome dosage. Recent studies have demonstrated that small RNAs, mainly siRNAs and miRNAs, play an important role in maintaining the genome reconstruction and stability. However, to date, little is known regarding the role of small RNAs during the process of wide hybridisation and chromosome doubling, which is essential to elucidate the mechanism of polyploidisation. Therefore, the genetic and DNA methylation alterations and changes in the siRNA and miRNA were assessed during the formation of an allodiploid (genome: AB) and its allotetraploid (genome: AABB) between Brassica rapa (M-bM-^YM-^@) and Brassica nigra (M-bM-^YM-^B) in the present study.The phenotypic analysis exhibited that the allotetraploid had high heterosis compared with their parents and the allodiploid. The methylation-sensitive amplification polymorphism (MSAP) analysis indicated that the proportion of changes in the methylation pattern of the allodiploid was significantly higher than that found in the allotetraploid, while the DNA methylation ratio was higher in the parents than the allodiploid and allotetraploid. The high-throughput sequencing results obtained for the small RNAs showed that the expression levels of miRNAs increased in the allodiploid and allotetraploid compared with the parents, and the expression levels of siRNAs increased and decreased compared with the parents B. rapa and B. nigra, respectively. Moreover, the percentages of miRNAs increased with an increase in the polyploidy levels, but the percentages of siRNAs and DNA methylation alterations decreased with an increase in the polyploidy levels. Furthermore, 320 known and 52 novel miRNAs were obtained from the parents in both the allodiploid and allotetraploid. However, quantitative real-time polymerase chain reaction (qRT PCR) analysis showed that the expression levels of the targets genes were negatively corrected with the expressed miRNAs.The study showed that siRNAs and DNA methylation play an important role in maintaining the genome stability in the formation of an allotetraploid. The miRNAs regulate gene expression and induce the phenotype variation, which may play an important role in the occurrence of heterosis in the allotetraploid. The findings of this study may provide new information for elucidating that the allotetraploids have a growth advantage over the parents and the allodiploids. High throughput sequence of the parents (Brassica rapa and Brassica nigra) and their hybrids (allodiploid and allotetraploid)

Project description:MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are produced in diverse species and control gene expression and epigenetic regulation. Although physiological and developmental roles of miRNAs and siRNAs have been extensively studied in plants and animals, expression diversity and evolution of miRNAs and siRNAs in closely related species are poorly understood. Here we report comprehensive analyses of miRNA expression and siRNA distribution in two closely related species (Arabidopsis thaliana and A. arenosa), a natural allotetraploid (A. suecica), and two resynthesized allotetraploid lines (F1 and F7) derived from A. thaliana and A. arenosa. The siRNA populations present in A. thaliana were maintained in resynthesized allotetraploids and A. suecica. Although miRNA sequences were highly conserved, their expression patterns were highly variable between the allotetraploids and their progenitors. Significantly, many miRNAs were nonadditively expressed in the allotetraploids relative to the parents and preferentially degraded A. thaliana or A. arenosa targets. Stable inheritance of parental siRNAs in allopolyploids helps maintain genome stability in response to M-bM-^@M-^\genomic shockM-bM-^@M-^], whereas expression diversity of miRNAs and their target preference lead to interspecies variation in gene expression, growth, and development. NOTE: sff files unavailable for Samples AaL and F1L. 10 samples examined: Arabidopsis thaliana leaf, flower, Arabidopsis arenosa leaf and flower, F1 synthetic allopolyploid leaf and flower, F7 synthetic allopolyploid leaf and flower, Arabidopsis suecica leaf and flower. To determine small RNA profiles in Arabidopsis allotetraploids and their progenitors, we made 10 small RNA libraries from rosette leaves (L) and flower buds (F) in five lines, A. thaliana, A. arenosa, Allo(F1), Allo733(F7), and A. suecica. To examine expression of small RNAs among related species and their hybrids, we employed miRNA microarrays and compared small RNA levels.

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The role of small RNAs in wide hybridisation and allopolyploidisation between Brassica rapa and Brassica nigra

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