Nitrate reutilization mechanisms in the tonoplast of two Brassica napus genotypes with different nitrogen use efficiency

Nitrogen Use Efficiency Is Mediated by Vacuolar Nitrate Sequestration Capacity in Roots of Brassica napus

“…Several studies revealed the close relationship between NO 3 2 content and NUE in plant tissues (Shen et al, 2003;Zhang et al, 2012;Tang et al, 2013;Han et al, 2015a). When plants are sufficiently illuminated, NO 3 2 assimilation efficiency significantly increase in shoots compared with roots (Smirnoff and Stewart, 1985;Tang et al, 2013).…”

“…2 cannot be efficiently assimilated because the enzyme nitrate reductase (NR) is cytosolic (Shen et al, 2003;Han et al, 2015a). However, retranslocation of NO 3 2 from the vacuole to the cytosol will permit its immediate assimilation and utilization.…”

“…NO 3 2 assimilatory system in the cytoplasm is sufficient for its assimilation when it is transported out of the vacuoles. Therefore, NO 3 2 use efficiency could in part be dependent on vacuolar-cytosolic NO 3 2 shortdistance transport in plant tissues (Martinoia et al, 1981;Shen et al, 2003;Zhang et al, 2012;Han et al, 2015a).…”

“…Evidently, NO 3 2 use efficiency is regulated by both NO 3 2 long-distance transport from root to shoot and short-distance transport and distribution between vacuoles and cytoplasm within cells (Glass et al, 2002;Dechorgnat et al, 2011;Han et al, 2015a). Although vacuoles compartment excess NO 3 2 that accumulates in plant cells (Granstedt and Huffaker, 1982;Krebs et al, 2010), neither NO 3 2 inducible NR genes (NIA1 and NIA2; Fan et al, 2007;Han et al, 2015a) nor the NO 3 2 long-distance transport gene NRT1.5 (Lin et al, 2008) are regulated by vacuolar NO 3 2 , even though they are essential for NO 3 2 assimilation.…”

“…Although vacuoles compartment excess NO 3 2 that accumulates in plant cells (Granstedt and Huffaker, 1982;Krebs et al, 2010), neither NO 3 2 inducible NR genes (NIA1 and NIA2; Fan et al, 2007;Han et al, 2015a) nor the NO 3 2 long-distance transport gene NRT1.5 (Lin et al, 2008) are regulated by vacuolar NO 3 2 , even though they are essential for NO 3 2 assimilation. Only NO 3 2 transported from the vacuole to the cytosol can play a role in regulating NO 3 2 inducible genes.…”