Ochieng Wyckliffe Ayoma, Wei Li, Wagutu Godfrey Kinyori, Xian Ling, Muthui Samuel Wamburu, Ogada Stephen, Otieno Duncan Ochieng, Linda Elive Limunga, Liu Fan
Core Botanical Gardens/Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
Sino-Africa Joint Research Centre, Chinese Academy of Sciences, Wuhan 430074, China.
Plants (Basel). 2023 Nov 16;12(22):3875. doi: 10.3390/plants12223875.
Ammonium toxicity in macrophytes reduces growth and development due to a disrupted metabolism and high carbon requirements for internal ammonium detoxification. To provide more molecular support for ammonium detoxification in the above-ground and below-ground parts of , we separated (using hermetic bags) the aqueous medium surrounding the below-ground from that surrounding the above-ground and explored the genes in these two regions. The results showed an upregulation of asparagine synthetase genes under high ammonium concentrations. Furthermore, the transcriptional down and/or upregulation of other genes involved in nitrogen metabolism, including glutamate dehydrogenase, ammonium transporter, and aspartate aminotransferase in above-ground and below-ground parts were crucial for ammonium homeostasis under high ammonium concentrations. The results suggest that, apart from the primary pathway and alternative pathway, the asparagine metabolic pathway plays a crucial role in ammonium detoxification in macrophytes. Therefore, the complex genetic regulatory network in contributes to its ammonium tolerance, and the above-ground part is the most important in ammonium detoxification. Nevertheless, there is a need to incorporate an open-field experimental setup for a conclusive picture of nitrogen dynamics, toxicity, and the molecular response of in the natural environment.
大型植物中的铵毒性会因新陈代谢紊乱以及内部铵解毒所需的高碳需求而降低生长和发育。为了为大型植物地上和地下部分的铵解毒提供更多分子支持，我们（使用密封袋）将地下周围的水介质与地上周围的水介质分开，并探索了这两个区域中的基因。结果表明，在高铵浓度下天冬酰胺合成酶基因上调。此外，在高铵浓度下，地上和地下部分中参与氮代谢的其他基因（包括谷氨酸脱氢酶、铵转运蛋白和天冬氨酸转氨酶）的转录下调和/或上调对于铵稳态至关重要。结果表明，除了主要途径和替代途径外，天冬酰胺代谢途径在大型植物的铵解毒中起关键作用。因此，大型植物中复杂的遗传调控网络有助于其耐铵性，并且地上部分在铵解毒中最为重要。然而，需要纳入一个野外实验装置，以获得大型植物在自然环境中的氮动态、毒性和分子反应的确切情况。
