Silencing of DGAT1 in tobacco causes a reduction in seed oil content

The 679-bp fragment corresponding to nt 615-1293 of tobacco DGAT1 (GenBank, AF129003) was used to create intron-containing construct expressing hpRNA for silencing endogenous DGAT1 gene of Nicotiana tabacum. The oil content in mature seeds of transgenic lines was reduced by 9 to 49%. The transgenic tobacco, designated Sil7, is correlated with reduced triacylglycerol (TAG) contents in different tissues, including leaves, stems, roots, petals and mature seeds. We show that the reduction of DGAT1 transcript level in transgenic tobacco mediated by hpRNA is correlated with the decrease of oil content in different tissues. In company with the decrease of average seed weight, seed oil content reduced, whereas protein and sugar content increased in the seeds of transgenic lines. There is a reversed relation between the deposition of oil and the synthesis of protein and sugar in the seeds of transgenic lines.