| Autor: |
Cheng Qin, Weiqiang Qian, Wenfeng Wang, Yue Wu, Chunmei Yu, Xinhang Jiang, Daowen Wang, Ping Wu |
| Předmět: |
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| Zdroj: |
Proceedings of the National Academy of Sciences of the United States of America; 11/25/2008, Vol. 105 Issue 47, p18308-18313, 6p, 4 Graphs |
| Abstrakt: |
Higher plant species differ widely in their growth responses to ammonium (NH+4). However, the molecular genetic mechanisms underlying NH+4 sensitivity in plants remain unknown. Here, we report that mutations in the Arabidopsis gene encoding GDP- mannose pyrophosphorylase (GMPase) essential for synthesizing GDP-mannose confer hypersensitivity to NH+4. The in planta activities of WT and mutant GMPases all were inhibited by NH+4, but the magnitude of the inhibition was significantly larger in the mutant. Despite the involvement of GDP-mannose in both L-ascorbic acid (AsA) and N-glycoprotein biosynthesis, defective protein glycosylation in the roots, rather than decreased AsA content, was linked to the hypersensitivity of GMPase mutants to NH+4. We conclude that NH+4 inhibits GMPase activity and that the level of GMPase activity regulates Arabidopsis sensitivity to NH+4. Further analysis showed that defective N-glycosylation of proteins, unfolded protein response, and cell death in the roots are likely important downstream molecular events involved in the growth inhibition of Arabidopsis by NH+4. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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