Abstract
To investigate whether the plastid ω-3 fatty acid desaturase gene NtFAD7 was silenced by RNAi, we produced transgenic tobacco plants that oerexpress NtFAD7 dsRNA. In the transgenic tobacco, the α-linolenic acid content of plastid lipids, MGDG, DGDG and PG, decreased remarkably, and endogenous NtFAD7 mRNA was not detected. (2002 annual meeting of the JSPP). Low molecul RNAs were purifyed from the transgenic tobacco plants, and then siRNA was detected by using of the NtFAD7 probe. The α-linolenic acid of extraplastid lipids, PC, PE and PI, can be thought to be synthesized by the ER ω-3 fatty acid desaturase NtFAD3 mainly. The α-linolenic acid content of these lipid classes in the transgenic plants also decreased and the amout of NtFAD3 mRNA decresed by about 30 - 75 % of the control. These resurts indicated that the NtFAD7 dsRNA and/or siRNA supressed heterologous target NtFAD3 gene weakly.
