Skip to main content
padlock icon - secure page this page is secure

Free Content Urea retranslocation from senescing Arabidopsis leaves is promoted by DUR3‐mediated urea retrieval from leaf apoplast

Download Article:
In plants, urea derives either from root uptake or protein degradation. Although large quantities of urea are released during senescence, urea is mainly seen as a short‐lived nitrogen (N) catabolite serving urease‐mediated hydrolysis to ammonium. Here, we investigated the roles of DUR3 and of urea in N remobilization. During natural leaf senescence urea concentrations and DUR3 transcript levels showed a parallel increase with senescence markers like ORE1 in a plant age‐ and leaf age‐dependent manner. Deletion of DUR3 decreased urea accumulation in leaves, whereas the fraction of urea lost to the leaf apoplast was enhanced. Under natural and N deficiency‐induced senescence DUR3 promoter activity was highest in the vasculature, but was also found in surrounding bundle sheath and mesophyll cells. An analysis of petiole exudates from wild‐type leaves revealed that N from urea accounted for >13% of amino acid N. Urea export from senescent leaves further increased in ureG‐2 deletion mutants lacking urease activity. In the dur3 ureG double insertion line the absence of DUR3 reduced urea export from leaf petioles. These results indicate that urea can serve as an early metabolic marker for leaf senescence, and that DUR3‐mediated urea retrieval contributes to the retranslocation of N from urea during leaf senescence.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Keywords: leaf senescence; nitrogen efficiency; phloem transport; urea metabolism; urea uptake; urease

Document Type: Research Article

Publication date: February 1, 2015

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more