Identification of marneral synthase, which is critical for growth and development in Arabidopsis
Article first published online: 1 OCT 2012
© 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd
The Plant Journal
Volume 72, Issue 5, pages 791–804, December 2012
How to Cite
Go, Y. S., Lee, S. B., Kim, H. J., Kim, J., Park, H.-Y., Kim, J.-K., Shibata, K., Yokota, T., Ohyama, K., Muranaka, T., Arseniyadis, S. and Suh, M. C. (2012), Identification of marneral synthase, which is critical for growth and development in Arabidopsis. The Plant Journal, 72: 791–804. doi: 10.1111/j.1365-313X.2012.05120.x
- Issue published online: 22 NOV 2012
- Article first published online: 1 OCT 2012
- Accepted manuscript online: 8 AUG 2012 11:25AM EST
- Received 20 March 2012; revised 28 July 2012; accepted 6 August 2012; published online 1 October 2012.
- growth and development;
- marneral synthase;
- oxidosqualene cyclase;
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.