In higher plants, NO3− can induce its own uptake and the magnitude of this induction is positively related to the external anion concentration. This phenomenon has been characterized in both herbaceous and woody plants. Here, different adaptation strategies of roots from two maize (Zea mays L., ZmAGOs) inbred lines differing in nitrogen use efficiency (NUE) and exhibiting different timing of induction were discussed by investigating NO3−-induced changes in their transcriptome. Lo5 line (high NUE) showing the maximum rate of NO3− uptake 4 h after the provision of 200 μmol/L NO3− treatment modulated a higher number of transcripts relative to T250 (low NUE) that peaked after 12 h. The two inbred lines share only 368 transcripts that are modulated by the treatment with NO3− and behaved differently when transcripts involved in anion uptake and assimilation were analyzed. T250 line responded to the NO3− induction modulating this group of genes as reported for several plant species. On the contrary, the Lo5 line did not exhibit during the induction changes in this set of genes. Obtained data suggest the importance of exploring the physiological and molecular variations among different maize genotypes in response to environmental clues like NO3− provision, in order to understand mechanisms underlying NUE.
Zamboni A, Astolfi S, Zuchi S, Pii Y, Guardini K, Tononi P, Varanini Z (2014) Nitrate induction triggers different transcriptional changes in a high and a low nitrogen use efficiency maize inbred line. J Integr Plant Biol 56: 1080-1094. doi: 10.1111/jipb.12214