Main conclusion

Overexpression of BnaC02.TPS8 increased low N and high sucrose-induced anthocyanin accumulation.

Abstract

Anthocyanin plays a crucial role in safeguarding photosynthetic tissues against high light, UV radiation, and oxidative stress. Their accumulation is triggered by low nitrogen (N) stress and elevated sucrose levels in Arabidopsis. Trehalose-6-phosphate (T6P) serves as a pivotal signaling molecule, sensing sucrose availability, and carbon (C) metabolism. However, the mechanisms governing the regulation of T6P synthase (TPS) genes responsible for anthocyanin accumulation under conditions of low N and high sucrose remain elusive. In a previous study, we demonstrated the positive impact of a cytoplasm-localized class II TPS protein ‘BnaC02.TPS8’ on photosynthesis and seed yield improvement in Brassica napus. The present research delves into the biological role of BnaC02.TPS8 in response to low N and high sucrose. Ectopic overexpression of BnaC02.TPS8 in Arabidopsis seedlings resulted in elevated shoot T6P levels under N-sufficient conditions, as well as an increased carbon-to-nitrogen (C/N) ratio, sucrose accumulation, and starch storage under low N conditions. Overexpression of BnaC02.TPS8 in Arabidopsis heightened sensitivity to low N stress and high sucrose levels, accompanied by increased anthocyanin accumulation and upregulation of genes involved in flavonoid biosynthesis and regulation. Metabolic profiling revealed increased levels of intermediate products of carbon metabolism, as well as anthocyanin and flavonoid derivatives in BnaC02.TPS8-overexpressing Arabidopsis plants under low N conditions. Furthermore, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) analyses demonstrated that BnaC02.TPS8 interacts with both BnaC08.TPS9 and BnaA01.TPS10. These findings contribute to our understanding of how TPS8-mediated anthocyanin accumulation is modulated under low N and high sucrose conditions.

中文翻译：

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油菜海藻糖-6-磷酸合成基因 BnaC02.TPS8 的过表达赋予拟南芥对低氮和高蔗糖诱导的花青素积累的敏感性

主要结论

BnaC02.TPS8的过表达增加了低氮和高蔗糖诱导的花青素积累。

抽象的

花青素在保护光合组织免受强光、紫外线辐射和氧化应激方面发挥着至关重要的作用。它们的积累是由拟南芥中的低氮 (N) 胁迫和蔗糖水平升高引发的。海藻糖 6-磷酸 (T6P) 是一种关键的信号分子，可感知蔗糖的可用性和碳 (C) 代谢。然而，在低氮和高蔗糖条件下负责花青素积累的T6P合酶（TPS）基因的调节机制仍然难以捉摸。在之前的一项研究中，我们证明了细胞质定位的 II 类 TPS 蛋白“BnaC02.TPS8”对甘蓝型油菜光合作用和种子产量提高的积极影响。本研究深入探讨了BnaCO2.TPS8响应低氮和高蔗糖的生物学作用。拟南芥幼苗中BnaC02.TPS8的异位过表达导致氮充足条件下地上部 T6P 水平升高，以及低氮条件下碳氮 (C/N) 比、蔗糖积累和淀粉储存增加。拟南芥中BnaC02.TPS8的过度表达增强了对低氮胁迫和高蔗糖水平的敏感性，同时伴随着花青素积累的增加以及参与类黄酮生物合成和调节的基因的上调。代谢分析揭示了在低氮条件下过表达BnaC02.TPS8的拟南芥植物中碳代谢中间产物以及花青素和类黄酮衍生物水平的增加。此外，酵母双杂交 (Y2H) 和双分子荧光互补 (BiFC) 分析表明 BnaC02.TPS8 与 BnaC08.TPS9 和 BnaA01.TPS10 相互作用。这些发现有助于我们了解在低氮和高蔗糖条件下如何调节 TPS8 介导的花青素积累。