In Planta Variation of Volatile Biosynthesis: An Alternative Biosynthetic Route to the Formation of the Pathogen-induced Volatile Homoterpene DMNT Via Triterpene Degradation in Arabidopsis Roots

Author

Reza Sohrabi
Jung Hyun Huh
Somayesadat Badieyan
Liva Harinantenaina Rakotondraibe
Daniel J. Kliebenstein
Pablo Sobrado, Missouri University of Science and TechnologyFollow
Dorothea Tholl

Abstract

Plant-derived volatile compounds such as terpenes exhibit substantial structural variation and serve multiple ecological functions. Despite their structural diversity, volatile terpenes are generally produced from a small number of core 5- to 20-carbon intermediates. Here, we present unexpected plasticity in volatile terpene biosynthesis by showing that irregular homo/norterpenes can arise from different biosynthetic routes in a tissue specific manner. While Arabidopsis thaliana and other angiosperms are known to produce the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) or its C16-analog (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene by the breakdown of sesquiterpene and diterpene tertiary alcohols in aboveground tissues, we demonstrate that Arabidopsis roots biosynthesize DMNT by the degradation of the C30 triterpene diol, arabidiol. The reaction is catalyzed by the Brassicaceae-specific cytochrome P450 monooxygenase CYP705A1 and is transiently induced in a jasmonate-dependent manner by infection with the root-rot pathogen Pythium irregulare. CYP705A1 clusters with the arabidiol synthase gene ABDS, and both genes are coexpressed constitutively in the root stele and meristematic tissue. We further provide in vitro and in vivo evidence for the role of the DMNT biosynthetic pathway in resistance against P. irregulare. Our results show biosynthetic plasticity in DMNT biosynthesis in land plants via the assembly of triterpene gene clusters and present biochemical and genetic evidence for volatile compound formation via triterpene degradation in plants.

Recommended Citation

R. Sohrabi et al., "In Planta Variation of Volatile Biosynthesis: An Alternative Biosynthetic Route to the Formation of the Pathogen-induced Volatile Homoterpene DMNT Via Triterpene Degradation in Arabidopsis Roots," Plant Cell, vol. 27, no. 3, pp. 874 - 890, Oxford University Press; American Society of Plant Biologists, Jan 2015.

The definitive version is available at https://doi.org/10.1105/tpc.114.132209

Department(s)

Chemistry

Publication Status

Free Access

Comments

National Science Foundation, Grant 1021384

International Standard Serial Number (ISSN)

1532-298X; 1040-4651

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Oxford University Press; American Society of Plant Biologists, All rights reserved.

Publication Date

01 Jan 2015

PubMed ID

25724638