Evidence for a nitrate-independent function of the nitrate sensor NRT1.1 in Arabidopsis thaliana.
NRT1.1 is a putative nitrate sensor and is involved in many nitrate-dependent responses. On the other hand, a nitrate-independent function of NRT1.1 has been implied, but the clear-cut evidence is unknown. We found that NRT1.1 mutants showed enhanced tolerance to concentrated ammonium as sole N source in Arabidopsis thaliana. This unique phenotype was not observed in mutants of NLP7, which has been suggested to play a role in the nitrate-dependent signaling pathway. Our real-time PCR analysis, and evidence from a literature survey revealed that several genes relevant to the aliphatic glucosinolate-biosynthetic pathway were regulated via a nitrate-independent signal from NRT1.1. When taken together, the present study strongly suggests the existence of a nitrate-independent function of NRT1.1.
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. takushi@biol.s.u-tokyo.ac.jp
Takushi
T
Hachiya
Yusuke
Y
Mizokami
Kazunori
K
Miyata
Danny
D
Tholen
Chihiro K
CK
Watanabe
Ko
K
Noguchi
D027321:Anion Transport Proteins / Q000378:metabolism*; D017360:Arabidopsis / Q000254:growth & development* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005961:Glucosinolates / Q000235:genetics*; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D009566:Nitrates / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development; D018520:Plant Shoots / Q000254:growth & development; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
D027321:Anion Transport Proteins; D005961:Glucosinolates; C101492:NRT1.1 protein, Arabidopsis; D009566:Nitrates; D010940:Plant Proteins; D000644:Quaternary Ammonium Compounds