Bovet Lucien, Cheval Cecilia, Hilfiker Aurore, Battey James, Langlet Delphine, Broye Herve, Schwaar Joanne, Ozelley Pierrick, Lang Gerhard, Bakaher Nicolas, Laparra Helene, Goepfert Simon
Philip Morris International R&D, Philip Morris Products SA, CH-2000 Neuchâtel, Switzerland.
Plants (Basel). 2019 Nov 11;8(11):492. doi: 10.3390/plants8110492.
Senescence is a genetically controlled mechanism that modifies leaf chemistry. This involves significant changes in the accumulation of carbon- and nitrogen-containing compounds, including asparagine through the activity of asparagine synthetases. These enzymes are required for nitrogen re-assimilation and remobilization in plants; however, their mechanisms are not fully understood. Here, we report how leaf curing-a senescence-induced process that allows tobacco leaves to dry out-modifies the asparagine metabolism. We show that leaf curing strongly alters the concentration of the four main amino acids, asparagine, glutamine, aspartate, and glutamate. We demonstrate that detached tobacco leaf or stalk curing has a different impact on the expression of asparagine synthetase genes and accumulation of asparagine. Additionally, we characterize the main asparagine synthetases involved in the production of asparagine during curing. The expression of and genes is upregulated during curing. The and tobacco plant lines display significant alterations in the accumulation of asparagine, glutamine, and aspartate relative to wild-type plants. These results support the idea that ASN1 and ASN5 are key regulators of asparagine metabolism during leaf curing.
衰老 是一种改变叶片化学成分的基因控制机制。这涉及到含碳和含氮化合物积累的显著变化，包括通过天冬酰胺合成酶的活性产生天冬酰胺。这些酶是植物中氮再同化和再转运所必需的；然而，它们的机制尚未完全了解。在这里，我们报告了叶片调制——一个由衰老诱导的使烟草叶片干燥的过程——如何改变天冬酰胺代谢。我们表明，叶片调制强烈改变了四种主要氨基酸，即天冬酰胺、谷氨酰胺、天冬氨酸和谷氨酸的浓度。我们证明，离体烟草叶片或叶柄调制对天冬酰胺合成酶基因的表达和天冬酰胺的积累有不同的影响。此外，我们鉴定了调制过程中参与天冬酰胺产生的主要天冬酰胺合成酶。在调制过程中， 和 基因的表达上调。与野生型植物相比， 和 烟草品系在天冬酰胺、谷氨酰胺和天冬氨酸的积累上表现出显著变化。这些结果支持了ASN1和ASN5是叶片调制过程中天冬酰胺代谢关键调节因子的观点。
