Plants can respond and adapt to changes in the internal content of carbon and nitrogen by using organic compounds that widely differ in their carbon/nitrogen ratio. Among them, the amides asparagine and glutamine are believed to be preferred by most plants, including Arabidopsis. However, increases in the ureides allantoin and/or allantoate concentrations have been observed in different plant species under several environmental conditions. In this work, changes in the ratio between carbon skeletons and reduced nitrogen were investigated by varying the concentrations of nitrogen and sucrose in the growth media. Allantoin accumulation was observed when plants were grown in media with high ammonia concentrations. This increase was reverted by adding sucrose as additional carbon source. Moreover, mutant plants with a decreased capability to degrade allantoin showed a compromised growth compared to WT in ammonia supplemented media. Together, our results indicate that allantoin accumulation is induced by low carbon/nitrogen ratio and suggest that its degradation is critical for proper plant growth and development.

植物可以通过使用碳/氮比差异很大的有机化合物来应对和适应碳和氮的内部含量的变化。其中，酰胺类天冬酰胺和谷氨酰胺被认为是包括拟南芥在内的大多数植物所优选的。然而，在几种环境条件下，已经在不同植物物种中观察到尿素尿囊素和/或尿囊酸酯浓度的增加。在这项工作中，通过改变生长培养基中氮和蔗糖的浓度，研究了碳骨架与还原氮之间比率的变化。当植物在高氨浓度的培养基中生长时，观察到尿囊素积累。通过添加蔗糖作为额外的碳源可以抵消这种增加。此外，在氨水补充培养基中，与野生型相比，降解尿囊素能力降低的突变植株显示出受损的生长。总之，我们的结果表明尿囊素的积累是由低碳/氮比引起的，并表明其降解对于植物的正常生长和发育至关重要。