The columbamine O-methyltransferase gene (CoOMT) is capable of increasing alkaloid content in transgenic tobacco plants.

BACKGROUND: In the alkaloid biosynthetic pathways of Stephania and Rannunculaceae, columbamine O-methyltransferase (CoOMT) is an important enzyme that catalyses the formation of the tetrahydropalmatin (rotundin) biosynthesis pathway. In this study, the transgenic construct pBI121-35S-CoOMT-cmyc-Kdel was designed successfully. METHODS AND RESULTS: The real-time RT-PCR results proved that the CoOMT transgene was successfully introduced into Nicotiana tabacum L. plants and produced mRNA. Its transcription levels in three transgenic tobacco lines, T0-7, T0-9, and T0-20, in the T0 generation were higher than those in wild-type tobacco plants. By analysing Western blots and ELISAs, three T0 generation transgenic tobacco lines also expressed recombinant CoOMT (rCoOMT) protein with a molecular weight of approximately 40 kDa, and its contents ranged from 0.048 µg mg-1 to 0.177 µg mg-1. These data illustrated that the CoOMT transgene was expressed; thus, the rCoOMT protein synthesis efficiency increased significantly in comparison with that of the wild-type tobacco plants. The total alkaloid contents ranged from 2.12 g 100 g-1 (of dry weight) to 3.88 g 100 g-1 (of dry weight). The T0-20 plant had the highest total alkaloid content (3.88 g 100 g-1 of dry weight), followed by the T0-7 line (2.75 g 100 g-1 of dry weight). The total alkaloid contents of the CoOMT transgenic tobacco lines increased by approximately 1.09-1.83-fold compared to the wild-type tobacco plants. CONCLUSIONS: This is the first study on the transformation and expression of the CoOMT gene in N. tabacum plants. Initial results of the analysis of transgenic plants proved that the transgenic structure pBI121- CoOMT-Cmyc-Kdel can be used for transformation into Stephania plants.

GmDREB6, a soybean transcription factor, notably affects the transcription of the NtP5CS and NtCLC genes in transgenic tobacco under salt stress conditions.

Soil is contaminated with salinity, which inhibits plant growth and development and reduces crop yields. The DREB (dehydration responsive element binding protein) gene responds to salt stresses through enhanced transcriptional expression and activation of genes involved in plant salinity resistance. In this study, we present the results of the analysis of the expression of the GmDREB6 transgene, a gene that encodes the soybean DREB6 transcription factor, regulating the transcription of the NtP5CS and NtCLC genes in transgenic tobacco under salt stress conditions. The transcription of GmDREB6, NtP5CS, and NtCLC in transgenic tobacco lines was confirmed by qRT-PCR. Under salt stress conditions, the GmDREB6 gene transcription levels in the transgenic tobacco lines L1 and L9 had increased from 2.40- to 3.22- fold compared with the condition without salinity treatment. Two transgenic lines, L1 and L9, had transcription levels of the P5CS gene that had increased from 1.24- to 3.60- fold compared with WT plants. For the NtCLC gene, under salt stress conditions, the transgenic lines had transcription levels that had increased by 3.65-4.54 (fold) compared with WT plants (P < 0.05). The L1-transgenic tobacco line showed simultaneous expression of both the GmDREB6 transgene and two intrinsic genes, the NtP5CS and NtCLC genes. This study demonstrated that expression of the GmDREB6 gene from soybean increases the transcription levels of the NtP5CS and NtCLC genes in transgenic tobacco plants under salt stress conditions. The analysis results have suggested that the GmDREB6 gene is a potential candidate for improving the salt tolerance of plants, opening up research and development opportunities for salt stress-tolerant crops to respond to climate change and the rise in sea levels.