Abstract
Background: Tobacco seed lipid is a promising non-edible feedstock for biodiesel production. In order to meet the increasing demand, achieving high seed lipid content is one of the major goals in tobacco seed production. The TT8 gene and its homologs negatively regulate seed lipid accumulation in Arabidopsis and Brassica species. We speculated that manipulating the homolog genes of TT8 in tobacco could enhance the accumulation of seed lipid.Results: In this present study, we found that the TT8 homolog genes in tobacco, NtAn1a and NtAn1b, were highly expressed in developing seed. Targeted mutagenesis of NtAn1 genes were created by the CRISPR-Cas9 based gene editing technology. Due to the defect of PAs biosynthesis, mutant seeds showed a phenotype of yellow seed coat. Seed lipid accumulation was enhanced by about 18% and 15% in two targeted mutant lines, respectively. Protein content was also significantly increased in mutant seeds. In addition, the seed yield related traits were not affected by the targeted mutagenesis of NtAn1 genes. Thus, the overall lipid productivity of the NtAn1 knockout mutants were dramatically enhanced. Conclusion: Tobacco NtAn1 genes regulate both PAs and lipid accumulation in the process of seed development. Targeted mutagenesis of NtAn1 genes could generate a yellow-seeded tobacco variety with high lipid and protein content. Furthermore, the present results revealed that CRISPR-Cas9 system could be employed in tobacco seed de novo domestication for biodiesel feedstock production.
Cholinephosphotransferase and Diacylglycerol Acyltransferase (Substrate Specificities at a Key Branch Point in Seed Lipid Metabolism)
