Reciprocal regulation between AtNRT2.1 and AtAMT1.1 expression and the kinetics of NH4+ and NO3− influxes

Our results show that AtNRT2.1 expression has a positive effect on the NH4+ ion influx, mediated by the HATS, as also occurs with AtAMT1.1 expression on the NO3− ion influx. AtNRT2.1 expression plays a key role in the regulation of AtAMT1.1 expression and in the NH4+ ion influx, differentiating the nitrogen source, and particularly, the lack of it. Nitrogen starvation produces a compensatory effect by AtAMT1.1 when there is an absence of the AtNRT2.1 gene. Our results also show that, in the atnrt2 mutant lacking both AtNRT2.1 and AtNRT2.2, gene functions present different kinetic parameters on the NH4+ ion influx mediated by the HATS, according to the source and availability of nitrogen. Finally, the absence of AMT1.1 also produces changes in the kinetic parameters of the NO3− influx, showing different Vmax values depending on the source of nitrogen available.