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BrFLC5: a weak regulator of flowering time in Brassica rapa

  • Xi Xi
  • Keyun Wei
  • Baozhen Gao
  • Jiahe Liu
  • Jianli Liang
  • Feng Cheng
  • Xiaowu Wang
  • Jian Wu
Original Article
  • 7 Downloads

Abstract

Key message

A splicing site mutation in BrFLC5, a non-syntenic paralogue of FLOWERING LOCUS C, was demonstrated to be related to flowering time variation in Brassica rapa.

Abstract

Flowering time regulation in Brassica rapa is more complex than in Arabidopsis, as there are multiple paralogues of flowering time genes in B. rapa. Brassica rapa contains four FLOWERING LOCUS C (FLC) genes, three of which are syntenic orthologues of AtFLC, while BrFLC5 is not. BrFLC1, BrFLC2, and BrFLC3 have been reported to be involved in flowering time regulation. However, BrFLC5 has thus far been deemed a pseudogene. We detected two alternative splicing patterns of BrFLC5 resulting from a nucleotide mutation (G/A) at the first nucleotide of intron 3 (named as Pi3+1(G/A)). Genotyping of BrFLC5Pi3 + 1(G/A) for 301 B. rapa accessions showed that this single nucleotide polymorphism was significantly related to flowering time variation (p < 0.001). In the collection, the frequency of the functional G allele (35.2%) was much lower than that of the nonfunctional A allele (59.1%); however, the frequency of the G allele was very high among the turnips (83.6%). An F2 population segregating at this locus was developed to analyze the genetic effect of BrFLC5. The result showed that the G allele individuals began to bolt two days later than the A allele individuals, indicating that BrFLC5 is a weak regulator of flowering time. BrFLC5 was expressed at the lowest level among the three analyzed BrFLCs. The late allele (G allele) was dominant to the early allele (A allele) at the BrFLC5 locus, which was in contrast to that of BrFLC1 and BrFLC2. This characteristic suggests that BrFLC5 would be more efficient for breeding premature bolting resistance in B. rapa.

Notes

Acknowledgements

This research work was supported by The National Key Research and Development Program of China (Grant No. 2016YFD0101007), and the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences, and the Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, P.R. China.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Supplementary material

122_2018_3139_MOESM1_ESM.doc (3.9 mb)
The position of the primers used for qRT-PCR. The arrows indicate the starting and terminating sites of the amplification. (a) The position of the primers used for qRT-PCR of BrFLC1. The forward primer is on E5 and the reverse primer is on E7, and they can be used to identify the alternative splicing that may exist on E6, E7, or I6 (Yuan et al. 2009). (b) The position of the primers used for qRT-PCR of BrFLC2. The forward primer is on E4 and the reverse primer is on E6. These primer pairs could identify the alternative splicing of E4 (Wu et al. 2012). (c) The primer position of qRT-PCR of BrFLC5. The forward primer crosses over E3 and E4, and the reverse primer is on E4, and can be used to identify the three types of alternative splicing of BrFLC5. (DOC 3990 kb)
122_2018_3139_MOESM2_ESM.doc (26 kb)
BrFLC5 full-length and cDNA sequences including annotations. (DOC 26 kb)
122_2018_3139_MOESM3_ESM.docx (15 kb)
cDNA sequences of the eight B. rapa accessions that were used to sequence the BrFLC5 alternative splicing in this study. (DOCX 14 kb)
122_2018_3139_MOESM4_ESM.xls (22 kb)
Primers designed to amplify BrFLC5, BrFLC1, and BrFLC2 from B. rapa. (XLS 21 kb)
122_2018_3139_MOESM5_ESM.xls (48 kb)
DTB of the germplasm collection and the corresponding BrFCL5 and BrFLC1 allele genotypes. (XLS 47 kb)
122_2018_3139_MOESM6_ESM.xls (40 kb)
DTB of the F2 population and the corresponding BrFCL5 allele genotype. (XLS 39 kb)

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijingChina

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