BMC Biotechnology最新文献

Background: Nicotine exhibits positive heterosis, and through its utilization, new tobacco varieties with ideal nicotine content have been bred. However, the potential mechanism underlying the increased transport and nicotine accumulation capacity in hybrids remain poorly understood.

Results: The purpose of this study was to reveal the regulatory role of the key gene NtGSTU10, which was identified during the early stages of nicotine heterosis. NtGSTU10-over expression lines were created through genetic transformation, and the nicotinic content, transport coefficient, and heterosis of NtGSTU10-over expression lines and wild-type tobacco plants were compared. The results suggested that the nicotine content in the leaves of V×OB7 (The over expression hybrids were produced by crossing Va116 as the female parent with OB7 as the male parent.) and V×OB12 (The over expression hybrids were produced by crossing Va116 as the female parent with OB12 as the male parent.) was significantly higher than that of the wild-type hybrid (V×B). Compared to the V×B, the nicotine transport coefficients of V×OB7 and V×OB12 were significantly increased by 39.50% and 40.67%, respectively; and nicotine heterosis was significantly increased by 120.07% and 127.59%, respectively. Further analysis showed that overexpression of the NtGSTU10 gene could result in up-regulated expression of genes related to nicotine synthesis (AOC, QS, ODC, and PAO) and transport (ABCB1, ABCC1, and ABCC2), as well as down-regulation of negative regulatory factors (ERF1, ETR, and JAZ).

Conclusions: The results indicated that overexpression of the NtGSTU10 gene promotes the synthesis and transport metabolism of nicotine in tobacco, positively contributing to increased nicotine content in hybrids. The research findings provide a molecular basis for regulating the nicotine transport and accumulation in hybrids, and also provide genetic resources for the targeted cultivation of new tobacco varieties with suitable nicotine content.

Background: The numerous hydroxyl groups in tannic acid (TA) and its tendency to form hydrogen bonds with proteins and carbohydrates are key factors contributing to its utility. TA-based enzyme immobilization supports provide flexible platforms for enzyme immobilization. chia gum (CG) can also trap significant amounts of water between its chains, preventing water loss from the gum and inhibiting enzyme leaching.

Results: In this study, TA, a natural linker molecule, was used to immobilize horseradish peroxidase (HRP) on chia gum (CG), serving as the natural support. On the created TA-CG support, HRP was successfully immobilized, with the maximum immobilization recovery (80%) observed at pH 7.0, 9 mg TA, and 20 U of the enzyme. Using a scanning electron microscope (SEM) and Fourier transform infrared (FTIR) technology, the chemical functional groups and morphological characteristics of the synthesized CG-TA-HRP were illustrated. After ten reuses, CG-TA-HRP demonstrated good reusability, with 65% retention. By comparing CG-TA-HRP to soluble HRP, the former exhibited better thermal stability up to 40 °C, a higher temperature optimum at 50 °C, and a pH optimum at 6.0. According to the K_m data, CG-TA-HRP exhibited a lower affinity for hydrogen peroxide (H₂O₂) and guaiacol and a higher oxidizing affinity to certain phenolic substrates. The prepared CG-TA-HRP demonstrated greater resistance to heavy metals, isopropanol, urea, and Triton X-100. During the 6-hour incubation period, soluble HRP removed 44% of the methyl orange, while immobilized HRP decolorized 78% of the dye.

Conclusions: The TA-linker molecule and chia gum are considered environmentally safe components in the production of CG-TA-HRP, making this an easy and eco-friendly method for enzyme immobilization.