Identification and characterization of a new dwarf locus DS-4 encoding an Aux/IAA7 protein in Brassica napus

  • Bo Zhao
  • Bo Wang
  • Zhaohong Li
  • Tao Guo
  • Junwei Zhao
  • Zhilin Guan
  • Kede LiuEmail author
Original Article


Key message

A dominant dwarfing gene, ds - 4 , encodes an Aux/IAA protein that negatively regulates plant stature through an auxin signaling pathway.


Dwarfism is an important agronomic trait affecting yield in many crop species. The molecular mechanisms underlying dwarfism in oilseed rape (Brassica napus) are poorly understood, restricting the progress of breeding dwarf varieties in this species. Here, we identified and characterized a new dwarf locus, DS-4, in B. napus. Next-generation sequencing-assisted genetic mapping and candidate gene analysis found that DS-4 encodes a nucleus-targeted auxin/indole-3-acetic acid (Aux/IAA) protein. A substitution (P87L) was found in the highly conserved degron motif of the Aux/IAA7 protein in the ds-4 mutant. This mutation co-segregated with the phenotype of individuals in the BC1F2 population. The P87L substitution was confirmed as the cause of the extreme dwarf phenotype by ectopic expression of the mutant allele BnaC05.iaa7 (equivalent to ds-4) in Arabidopsis. The P87L substitution blocked the interaction of BnaC05.iaa7 with TRANSPORT INHIBITOR RESPONSE 1 in the presence of auxin. The BnaC05.IAA7 gene is highly expressed in the cotyledons, hypocotyls, stems and leaves, but weakly in the roots and seeds of B. napus. Our findings provide new insights into the molecular mechanisms underlying dominant (gain-of-function) dwarfism in B. napus. Our identification of a distinct gene locus controlling plant height may help to improve lodging resistance in oilseed rape.



The research was supported by the National Key Research and Development Program of China (2016YFD0101007AA102602).

Compliance with ethical standards

Conflict of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.

Ethical standards

The authors declare that the experiments comply with the current laws of the country in which they were performed.

Supplementary material

122_2019_3290_MOESM1_ESM.pptx (552 kb)
a, Polymorphisms of the six INDELs and b, four SNP2CAPS markers were visualized on a 6% denaturing polyacrylamide gel and 3% agarose gel, respectively (PPTX 552 kb)
122_2019_3290_MOESM2_ESM.pptx (90 kb)
Alignment of amino acid sequences of BnaC05.IAA7 from the mutant ds-4, wild-type ZY821 and its homologs Bo5g093110 in Brassica oleracea TO1000. The conserved regions are indicated below the sequences with a black line. The red arrow indicates the Pro to Leu (P87L) mutation at position 87. Nuclear localization signals (NLS) are indicated by unfilled boxes (PPTX 90 kb)
122_2019_3290_MOESM3_ESM.xlsx (13 kb)
Sequence information of oligonucleotide primers used for mapping and cloning of DS-4 and for functional analysis of BnaC05.IAA7 in this study (XLSX 13 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina

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