Abstract: In this study, the coding region ofFritillaria unibracteatamevalonate kinase （FuMK） gene was inserted into pCambia2301-KY vector under the control of 35S promoter using homologous recombination. The recombinant vector was then introduced intoAgrobacterium tumefaciensGV3101. The floral dip method was used to transform the wild-typeArabidopsis thaliana. The transgenic plants were identified by kanamycin resistance followed by RCR verification. Phenotypes, terpenoid contents and defense enzyme activities of wild-type and transgenic plants were evaluated under normal and drought conditions, respectively. As a result, theFuMKgene showed higher expression level in aerial tissues than underground tissue. In comparison with wild-type plants, the transgenic plants displayed higher weight （P<0.01）, leaf length （P<0.05）, and leaf number （P<0.05）, suggesting the higher drought tolerance in transgenic plants. Moreover, the transgenic plants exhibited higher carotenoid and chlorophyll contents, phenylalanine ammonia-lyase （PAL）, superoxide dismutase （SOD） and peroxidase （POD） activities, but lower hydrogen peroxide （H2O2） and malondialdehyde （MDA） contents, compared to those of wild-type plants. Overall, this study confirmed that heterologous expression ofFuMKgene not only enhanced thein vivobiosynthesis of downstream terpenoid products, but also conferred tolerance to drought, thereby providing a basis and candidate genes for future metabolic engineering.

Key words: Fritillaria unibracteata, MVA pathway, mevalonate kinase, subcellular localization, drought tolerance