Abstract
Between the two major rice subspecies, indica varieties generally exhibit higher nitrate (NO3‒) uptake and nitrogen (N)-use efficiency (NUE) than japonica varieties. Introducing efficient NO3‒ utilization alleles from indica into japonica could improve NUE, and at the same time uncover unknown regulators of NO3‒ metabolism. Here, we identify OsWRKY23 as a key regulator of NO3‒ uptake and NUE differences between indica and japonica rice. The OsWRKY23indica allele exhibits reduced transcriptional activation of a negative regulator of auxin accumulation, DULL NITROGEN RESPONSE1 (DNR1). The resultant increase in auxin level improves NO3‒ uptake and assimilation, which ultimately enhances grain yield. Geographical and evolutionary analyses reveal overlapping distribution of OsWRKY23indica and DNR1indica, particularly in low-fertility soils, suggesting their involvement in the adaptation to low N conditions to improve NUE and grain yield. Incorporating the OsWRKY23-DNR1 module from indica rice represents a promising strategy to enhance japonica NUE, which is crucial for sustainable agriculture.