Nitrate is the major form of nitrogen used by plants in an aerobic crop cultivation scenario. Lamig et al. review recent additions to the already vast knowledge of nitrate signaling. A first line of regulation concerns nitrate uptake through post-transcriptional and post-translational regulation of nitrate transporters. Both low affinity (NRT1) and high affinity (NRT2) nitrate […]
Roots are dependent on shoot-produced sucrose for energy associated with growth and nutrient uptake. The CLAVATA3/ESR2-related peptides (CLEs) regulate several aspects of plant growth. Okamoto et al. present evidence on the involvement of CLEs in conveying the root sucrose demand to the shoot. Carbon starvation upregulates CLE2 and CLE3 and increases the translocation of CLE2 […]
Protein phosphorylation and dephosphorylation act as a switch regulating a multitude of protein properties, be it their activity, interaction with other proteins, stability, or even cellular localization. This review by Li et al. describs the many ways that protein phosphorylation contributes to iron uptake and homeostasis. The membrane localization of the iron transporter IRT1 is […]
In rice, the transcription factor N-mediated heading date-1 (Nhd1) activates the expression of Heading date 3a (Hd3a), a floral regulator gene and regulate flowering. Li et al. report the role of Nhd1 in nitrogen (N) use efficiency and N-dependent root growth in rice. nhd1 mutants were impaired in root growth when grown in low nitrate, […]
Ammonium is a nitrogen form preferred by many plant species. However, high ammonium concentrations lead to decreased primary root elongation due to membrane depolarization and lower apoplastic pH. Liu et al. report that ammonium toxicity results in iron-dependent reactive oxygen species (ROS) production and thereby decreases primary root elongation. Based on ammonium responsive transcriptome data, […]
Root growth is highly sensitive to nitrogen (N), and affected by both the form and distribution of N. The hormone auxin is a major player in root growth response to N heterogeneity. Devi et al. report on the intricate interplay of auxin and brassinosteroid (BR) signaling in determining the root growth response to low N, […]
In addition to its role as a nutrient and a developmental signal, nitrate regulates stress responses in plants. By homology to nitrate transporters previously identified in Arabidopsis as contributing to stress induced-nitrate allocation to roots (SINAR) and nitrogen use efficiency (NUE), Guan et al. identified OsNPF7.9 as having a similar role in rice. Osnpf7.9 mutants […]
When nitrogen or nitrate availability is high, symbiotic nodule generation is curtailed to conserve the associated energy cost. But how does the presence of nitrate interfere with nodulation and symbiosis? Previously, genetic studies identified nitrate unresponsive symbiosis (nrsym) mutants in Lotus japonicus in which nodule formation is insensitive to nitrate levels. Here, Misawa et al. […]
In addition to the vast array of metabolic and signaling roles, nitric oxide (NO) is prominently involved in low oxygen sensing in seeds and waterlogged plants. In Arabidopsis, the cytosolic nitrate reductase (NR) isoforms NIA1/NIA2 catalyze the reductive pathway of NO generation. NO sensing in plants constitute highly regulated proteasomal degradation of ethylene response transcription […]