Target genes, interacting proteins, ubiquitination sites, and primers for OsWRI1a functional analysis

Nitrogen (N) deficiency-induced increases in the root-to-shoot biomass
ratio in plants are adaptive in nature but suboptimal for agriculture.
Understanding the regulatory mechanisms governing this developmental
plasticity could help improve crop performance while reducing fertilizer
application. We identified OsWRI1a (WRINKLED1a) as a regulatory hub
coordinating rice root and shoot growth in response to external N supply,
thereby stabilizing the root-to-shoot ratio. In roots, OsWRI1a enhances
N-responsive development by promoting auxin accumulation. Meanwhile, shoot
OsWRI1a stimulates tiller development and therefore shoot growth. We
identified an elite OsWRI1a haplotype that minimizes root-to-shoot ratio
fluctuation under N deficiency, improving N-use efficiency (NUE) and grain
yield. Our findings reveal a central mechanism coordinating N-responsive
growth allocation for sustainable agriculture.