Abstract
The tobacco endoplasmic reticulum ω-3 fatty acid desaturase (NtFAD3) catalyzes the synthesis of α-linolenate in glycrolipids. A cosuppressed tobacco line was produced by introduction of the sense NtFAD3 transgene under the control of El2 promoter. In this line, the NtFAD3 siRNAs were generated. We introduced an RNAi vector containing an inverted repeat against the part of El2 promoter sequence into this cosuppressed line, and the resultant double transformant showed a recovered phenotype, namely increased α-linolenate content in associated with disappearance of NtFAD3 siRNA. The RNAi construct against the promoter sequence has been considered to cause RNA-directed DNA methylation, which would be followed by the conformational change of chromatin via histone modification. Here, histone modification arround the transgene sequence is investigated by immunoprecipitation of chromatin prepared from the cosuppressed plants and plants recovered from cosuppression.
