Depletion of carbohydrate reserves limits nitrate uptake during early regrowth in Lolium perenne L.

0476507 - ÚEB 2018 RIV GB eng J - Journal Article
Guo, Q. - Turnbull, M. - Song, J. - Roche, J. - Novák, Ondřej - Späth, J. - Jameson, P. E. - Love, J.
Depletion of carbohydrate reserves limits nitrate uptake during early regrowth in Lolium perenne L.
Journal of Experimental Botany. Roč. 68, č. 7 (2017), s. 1569-1583. ISSN 0022-0957. E-ISSN 1460-2431
R&D Projects: GA ČR(CZ) GA17-06613S
Institutional support: RVO:61389030
Keywords : Carbohydrate * Carbon * Cytokinin * Fructan * Lolium perenne * Nitrate transporter (NRT) * Nitrate uptake * Nitrogen * Nitrogen use efficiency (NUE) * Perennial ryegrass
OECD category: Plant sciences, botany
Impact factor: 5.354, year: 2017

The mechanisms linking C/N balance to N uptake and assimilation are central to plant responses to changing soil nutrient levels. Defoliation and subsequent regrowth of grasses both impact C partitioning, thereby creating a significant point of interaction with soil N availability. Using defoliation as an experimental treatment, we investigated the dynamic relationships between plant carbohydrate status and NO 3 responsive uptake systems, transporter gene expression, and nitrate assimilation in Lolium perenne L. High-and low-affinity NO 3 uptake was reduced in an N-dependent manner in response to a rapid and large shift in carbohydrate remobilization triggered by defoliation. This reduction in NO 3 uptake was rescued by an exogenous glucose supplement, confirming the carbohydrate dependence of NO 3 uptake. The regulation of NO 3 uptake in response to the perturbation of the plant C/N ratio was associated with changes in expression of putative high- and low-affinity NO 3 transporters. Furthermore, NO 3 assimilation appears to be regulated by the C-N status of the plant, implying a mechanism that signals the availability of C metabolites for NO 3 uptake and assimilation at the whole-plant level. We also show that cytokinins may be involved in the regulation of N acquisition and assimilation in response to the changing plant C/N ratio.
Permanent Link: http://hdl.handle.net/11104/0272988