Improving rice nitrogen-use efficiency by modulating a novel monouniquitination machinery for optimal root plasticity response to nitrogen.
Huang Y., Ji Z., Tao Y., Wei S., Jiao W., Fang Y., Jian P., Shen C., Qin Y., Zhang S., Li S., Liu X., Kang S., Tian Y., Song Q., Harberd NP., Wang S., Li S.
Plant nitrogen (N)-use efficiency (NUE) is largely determined by the ability of root to take up external N sources, whose availability and distribution in turn trigger the modification of root system architecture (RSA) for N foraging. Therefore, improving N-responsive reshaping of RSA for optimal N absorption is a major target for developing crops with high NUE. In this study, we identified RNR10 (REGULATOR OF N-RESPONSIVE RSA ON CHROMOSOME 10) as the causal gene that underlies the significantly different root developmental plasticity in response to changes in N level exhibited by the indica (Xian) and japonica (Geng) subspecies of rice. RNR10 encodes an F-box protein that interacts with a negative regulator of auxin biosynthesis, DNR1 (DULL NITROGEN RESPONSE1). Interestingly, RNR10 monoubiquitinates DNR1 and inhibits its degradation, thus antagonizing auxin accumulation, which results in reduced root responsivity to N and nitrate (NO3-) uptake. Therefore, modulating the RNR10-DNR1-auxin module provides a novel strategy for coordinating a desirable RSA and enhanced N acquisition for future sustainable agriculture.