Identification of marneral synthase,which is critical for growth and development in Arabidopsis |
| |
Authors: | Young S. Go Saet B. Lee Hae J. Kim Jungmook Kim Hyo‐Young Park Jeong‐Kook Kim Kyomi Shibata Takao Yokota Kiyoshi Ohyama Toshiya Muranaka Siméon Arseniyadis Mi C. Suh |
| |
Affiliation: | 1. Department of Plant Biotechnology, Chonnam National University, Gwangju 500‐757, Korea;2. Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 500‐757, Korea;3. School of Life Sciences and Biotechnology, Korea University, Seoul 136‐701, Korea;4. Department of Biosciences, Teikyo Univeristy, 1‐1 Toyosatodai, Utsunomiya 320‐8551, Japan;5. Department of Chemistry and Materials Science, Tokyo Institute of Technology, Tokyo 152‐8551, Japan;6. Department of Biotechnology, Osaka University, Osaka 565‐0871, Japan;7. Centre de Recherches de Gif, CNRS‐UPR 2301 Institut de Chimie des Substances Naturelles, ?91198 Gif‐sur‐Yvette Cedex, ?France |
| |
Abstract: | Plants produce structurally diverse triterpenoids, which are important for their life and survival. Most triterpenoids and sterols share a common biosynthetic intermediate, 2,3‐oxidosqualene (OS), which is cyclized by 2,3‐oxidosqualene cyclase (OSC). To investigate the role of an OSC, marneral synthase 1 (MRN1), in planta, we characterized a Arabidopsis mrn1 knock‐out mutant displaying round‐shaped leaves, late flowering, and delayed embryogenesis. Reduced growth of mrn1 was caused by inhibition of cell expansion and elongation. Marnerol, a reduced form of marneral, was detected in Arabidopsis overexpressing MRN1, but not in the wild type or mrn1. Alterations in the levels of sterols and triterpenols and defects in membrane integrity and permeability were observed in the mrn1. In addition, GUS expression, under the control of the MRN1 gene promoter, was specifically detected in shoot and root apical meristems, which are responsible for primary growth, and the mRNA expression of Arabidopsis clade II OSCs was preferentially observed in roots and siliques containing developing seeds. The eGFP:MRN1 was localized to the endoplasmic reticulum in tobacco protoplasts. Taken together, this report provides evidence that the unusual triterpenoid pathway via marneral synthase is important for the growth and development of Arabidopsis. |
| |
Keywords: | Arabidopsis growth and development marneral synthase marnerol oxidosqualene cyclase triterpenols |
|
|