Table 1.
Literature summary of the tissue expression and regulation of some NRT2s in higher plants
| Gene (Accession number) | Expression | Regulation | |
| Characterization | Technique | ||
| AtNRT2.1/2.2 (AF019748/AF01979) | Root cortical and epidermal cells | RT-PCR; GUS/GFP fusion | NO3−, sucrose and light induction; NH4+ and amino acids repression |
| AtNRT2.3 (AB015472) | Mainly in roots | RT-PCR | NO3− induction in shoots |
| AtNRT2.4 (AB015472) | Modest NO3− induction | ||
| AtNRT2.6 (AL353992) | - | ||
| AtNRT2.5 (AC012187) | NO3− repression; Glucose induction | ||
| AtNRT2.7 (AL163792) | Shoots; Embryo; seeds | RT-PCR; GUS/GFP fusion | NO3− insensity |
| ZmNRT2.1 (AY129953) | Root epidermis and cortex | RT-PCR; In situ hybridization | NO3− induction; Glucose down- and sucrose upregulation |
| ZmNRT2.2 (AY659965) | Root endodermis, centralcylinder and lateral primordia | ||
| NpNRT2 (Y08210) | Strong in epidermis and endodermis close to the root tip, week in the epidermis and lateral root primordia in the mature part of the root | RNA gel blot; In situ hybridization | NO3− induction |
| HvNRT2.1 | Root | RNA gel blot | NO3− and NO2− induction |
| OsNAR2.1 (AP008208) | Strongest in root epidermis and lower in cortex and stele | RT-PCR; GUS fusion | NO3−, light and sucrose upregulation; NH4+ repression |
| OsNRT2.1 (AP008519) | Whole roots; leaves; week in hulls and anthers | ||
| OsNRT2.2 (AP008519) | Whole roots; leaves; strong in hulls and anthers | ||
| OsNRT2.3a (AP003245) | Root stele; leaves; seed scutellum | ||
| OsNRT2.3b (AP003245) | light and sucrose upregulation | ||
| OsNRT2.4 (AP004614) | Adventitious root primordial; leaves; ends of the hull and in vascular tissue of the anther | NO3−, light and sucrose upregulation; NH4+ repression | |