Auxin-mediated nitrate signalling by NRT1.1 participates in the adaptive response of Arabidopsis root architecture to the spatial heterogeneity of nitrate availability. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Plant, Cell and Environment Année : 2014

Auxin-mediated nitrate signalling by NRT1.1 participates in the adaptive response of Arabidopsis root architecture to the spatial heterogeneity of nitrate availability.

Résumé

To optimize their nitrogen nutrition, plants are able to direct root growth in nitrate-rich patches. This depends in Arabidopsis on the NRT1.1 nitrate transporter/sensor. NRT1.1 was shown to display on homogenous medium, an auxin transport activity that lowers auxin accumulation in lateral roots and inhibits their growth at low nitrate. Using a split-root system, we explored the hypothesis that preferential lateral root growth in the nitrate-rich side involves the NRT1.1-dependent repression of lateral root growth in the low nitrate side. Data show that NRT1.1 acts locally to modulate both auxin levels and meristematic activity in response to the low nitrate concentration directly experienced by lateral roots leading to a repression of their growth. A stimulatory role of NRT1.1 in the high nitrate side, which does not rely on changes in auxin levels, is also observed. Altogether, our data suggest that NRT1.1 allows preferential root colonization of nitrate-rich patches by both preventing root growth in response to low nitrate, through modulation of auxin traffic, and stimulating root growth in response to high nitrate, through a yet uncharacterized mechanism. In addition, transcriptional regulation of NRT1.1 affects both mechanisms allowing plants to modulate the effect of nitrate on root branching.

Dates et versions

hal-00921002 , version 1 (19-12-2013)

Identifiants

Citer

Emmanuelle Mounier, Marjorie Pervent, Karin Ljung, Alain Gojon, Philippe Nacry. Auxin-mediated nitrate signalling by NRT1.1 participates in the adaptive response of Arabidopsis root architecture to the spatial heterogeneity of nitrate availability.. Plant, Cell and Environment, 2014, 37 (1), pp.162-74. ⟨10.1111/pce.12143⟩. ⟨hal-00921002⟩
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