Abstract
ω-3 fatty acid desaturase, which catalyzes the synthesis of trienoic fatty acids, is assumed to play an important role in plant adaptation to environmental stresses. In this study, two novel rice ω-3 desaturase genes (OsFAD7-1 and OsFAD7-2), with an extensive sequence similarity to the chloroplast-localized Arabidopsis ω-3 desaturase (AtFAD7), were characterized. The deduced amino acid sequences of OsFAD7-1 and OsFAD7-2 were 73% and 78% identical to that of AtFAD7, respectively. The N-termini of these genes contained a putative chloroplast transit peptide. RT-PCR analysis showed that their mRNAs highly accumulated in the leaf tissues. These observations suggest that these two genes encode the chloroplast-localized ω-3 desaturase. To clarify the physiological role of OsFAD7-1 and OsFAD7-2, transgenic rice plants, in which the corresponding intrinsic ω-3 desaturases are silenced by RNAi technique, were created. We have obtained several transgenic lines with reduced levels of TAs.
