Natural variation of OsWRKY23 drives difference in nitrate use efficiency between indica and japonica rice.

Between the two major rice subspecies, indica varieties generally exhibit higher nitrate (NO) uptake and nitrogen (N)-use efficiency (NUE) than japonica varieties. Introducing efficient NO utilization alleles from indica into japonica could improve NUE, and at the same time uncover unknown regulators of NO metabolism. Here, we identify OsWRKY23 as a key regulator of NO uptake and NUE differences between indica and japonica rice. The OsWRKY23 allele exhibits reduced transcriptional activation of a negative regulator of auxin accumulation, DULL NITROGEN RESPONSE1 (DNR1). The resultant increase in auxin level improves NO uptake and assimilation, which ultimately enhances grain yield. Geographical and evolutionary analyses reveal overlapping distribution of OsWRKY23 and DNR1, 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.