Agricultural Sciences in China 2008, 7(5): 521-534 © 2008, CAAS. All rights reserved. Published by Elsevier Ltd. May 2008 Expression in Arabidopsis of a Strawberry Linalool Synthase Gene Under the Control of the Inducible Potato PI2 Promoter YANG Li-mei 1, 2, 3 , Per Mercke 3 , Joop J A van Loon 2 , FANG Zhi-yuan 1 , Marcel Dicke 2 and Maarten A Jongsma 3 1 Institute of Vegetables & Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China 2 Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands 3 Plant Research International, P.O. Box 16, 6700 AA Wageningen, The Netherlands Abstract To investigate the role of inducible linalool in Arabidopsis-insect interactions, the FaNES1 linalool synthase (LIS) cDNA from strawberry with plastid targeting and a synthetic intron (LIS’) was placed under the control of the wound inducible proteinase inhibitor 2 (PI2) promoter from potato. The construct pBin-P PI2 -LIS’ was transformed to Arabidopsis thaliana ecotype Columbia 0. Kanamycin resistant T 0 seedlings were confirmed for the presence and transcription of the LIS’ gene by PCR analysis on genomic DNA and by RT-PCR analysis on RNA. Genomic and RT-PCR products were sequenced to confirm correct splicing of the synthetic intron. The expression of active linalool synthase by the P PI2 -LIS’ gene construct in the transgenic lines was assessed by measuring linalool emission using solid phase micro-extraction (SPME) GC-MS measurements after induction with methyl jasmonate. Among 30 tested independent T 2 transgenic lines, 10 exhibited linalool production. Linalool expression could be induced by methyl jasmonate treatment, but not by diamondback moth larvae. Key words: Aradidopsis, linalool synthase, potato proteins inhibitor, inducible promoter, methyl jasmonate, Plutella xylostella, induction, expression INTRODUCTION Terpenoids comprise one of the largest families of compounds produced by plants. They have many functions, and for example act as hormones, mediators of polysaccharide synthesis, photosynthetic pigments (chlorophyll and carotenoids), and membrane components (Chappell 1995). They also mediate interactions between plants and their environment: They are involved in interactions between plants and microorganisms, between plants and herbivorous arthropods or between plants and carnivorous arthropods (Cseke et al. 1998; Aharoni et al . 2003; 2006; Kappers et al. 2005). Moreover, plants may emit terpenoids that attract insect pollinators (Dobson 1993; Knudsen et al. 1993). Linalool (3,7-dimethyl-1,6-octadien-3-ol), a C10 monoterpene volatile, is present in the floral fragrance of diverse plant families. Due to its sweet, pleasant fragrance it is used extensively by the flavour and fragrance industry. Linalool mediates interactions among plants and other organisms, e.g., it has been shown to act either as an attractant or a repellent/ deterrent to a broad spectrum of pollinators, herbivores and parasitoids (Dicke et al . 1990; Raguso and Pichersky 1999; Wei and Kang 2006). For the purpose of our research, the latter aspect is of special interest. Attraction was documented for insects such as the tarnished plant bug (Chinta et al. Received 20 January, 2007 Accepted 21 April, 2008 Correspondence Maarten A Jongsma, E-mail: maarten.jongsma@wur.nl, Fax: +31-317-477109, Tel: +31-317-480932, Mobile: +31-630451274