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Identification of marneral synthase, which is critical for growth and development in Arabidopsis
Author(s) -
Go Young S.,
Lee Saet B.,
Kim Hae J.,
Kim Jungmook,
Park HyoYoung,
Kim JeongKook,
Shibata Kyomi,
Yokota Takao,
Ohyama Kiyoshi,
Muranaka Toshiya,
Arseniyadis Siméon,
Suh Mi C.
Publication year - 2012
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2012.05120.x
Subject(s) - arabidopsis , silique , meristem , endoplasmic reticulum , biology , ectopic expression , microbiology and biotechnology , atp synthase , mutant , gene , biochemistry
Summary 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 MRN 1, 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.