Nitrogen is critical in plant growth and productivity, making PTR/NRT1
transporters vital for rice growth. A study conducted by the team of
Xiaorong Fan from Nanjing Agricultural University in China characterized the
rice peptide transporter, OsPTR6, and examined its response to high and low
nitrate and ammonium availability.

OsPTR6 was overexpressed in transgenic Nipponbare cultivar to increase its
nitrogen use efficiency (NUE). Three transgenic lines, OE1, OE5 and OE6,
were produced and subjected to hydroponic growth experiments with different
nitrogen treatments. The results showed that the plant height and biomass of
the transgenic lines increased, and nitrogen accumulation and glutamine
synthetase (GS) activities were enhanced. However, nitrogen utilization
efficiency (NUE) decreased at high ammonium levels.

These suggest that overexpressing OsPTR6 increases rice growth but decreases
nitrogen use efficiency under high ammonium conditions.

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