Plant Molecular Biology

, Volume 78, Issue 1–2, pp 31–44 | Cite as

Nucleostemin-like 1 is required for embryogenesis and leaf development in Arabidopsis

  • Xiaomin Wang
  • Bo Xie
  • Maosheng Zhu
  • Zhongming Zhang
  • Zonglie Hong


Arabidopsis NSN1 encodes a nucleolar GTP-binding protein and is required for flower development. Defective flowers were formed in heterozygous nsn1/+ plants. Homozygous nsn1 plants were dwarf and exhibited severe defects in reproduction. Arrests in embryo development in nsn1 could occur at any stage of embryogenesis. Cotyledon initiation and development during embryogenesis were distorted in nsn1 plants. At the seedling stage, cotyledons and leaves of nsn1 formed upward curls. The curled leaves developed meristem-like outgrowths or hyperplasia tissues in the adaxial epidermis. Long and enlarged pavement cells, characteristic of the abaxial epidermis of wild type plants, were found in the adaxial epidermis in nsn1 leaves, suggesting a disoriented leaf polarity in the mutant. The important role of NSN1 in embryo development and leaf differentiation was consistent with the high level expression of the NSN1 gene in the developing embryos and the primordia of cotyledons and leaves. The CLAVATA 3 (CLV3) gene, a stem cell marker in the Arabidopsis shoot apical meristem (SAM), was expressed in expanded regions surrounding the SAM of nsn1 plants, and induced ectopically in the meristem-like outgrowths in cotyledons and leaves. The nsn1 mutation up-regulated the expression levels of several genes implicated in the meristem identity and the abaxial cell fate, and repressed the expression of other genes related to the specification of cotyledon boundary and abaxial identity. These results demonstrate that NSN1 represents a novel GTPase required for embryogenesis, leaf development and leaf polarity establishment in Arabidopsis.


Nucleostemin Embryogenesis Stem cell Leaf polarity Arabidopsis thaliana 



We thank ABRC (the Ohio State University) and Dr. Thomas Laux (University of Freiburg, Germany) for providing Arabidopsis seeds. This work was supported by NSF grants (MCB 0548525 and IOB 0543923) to Z.H. and a fellowship from the Chinese Scholarship Council (CSC) to M.Z.


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Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Xiaomin Wang
    • 1
  • Bo Xie
    • 1
  • Maosheng Zhu
    • 1
    • 2
  • Zhongming Zhang
    • 2
  • Zonglie Hong
    • 1
  1. 1.Department of Plant, Soil and Entomological Sciences and Program of Microbiology, Molecular Biology and BiochemistryUniversity of IdahoMoscowUSA
  2. 2.State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhanChina

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