Integrated molecular basis of nitrogen and phosphate signal networks in rice.

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N and P were two of the most important nutrient in rice. However, excess N and P fertilizer input caused deleterious effects on environment. Therefore, genetic breeding of high NUE and PUE cultivars is a desirable strategy in agricultural production. In this study, we show that NIN-like protein OsNLP3 which is the closet homolog of AtNLP7. In the sole nitrate condition, osnlp3 mutant lines exhibited significantly growth retardation compared to the WT which including the decreased shoot length and biomass, especially under high nitrate condition. Loss-of-OsNLP3 suppress a series of nitrate transporter and nitrate assimilatory genes. Moreover, N content of osnlp3 mutant were also reduced compared to the WT under both high nitrate and low nitrate condition, indicating that OsNLP3 is responsible for nitrate dependent growth in rice seedling stage. Like the case of AtNLP7 in Arabidopsis, OsNLP3 exhibited nitrate promoted nucleocytosolic shuttling phenomena. In addition, field trails demonstrate that osnlp3 exhibited decreased panicle number and grain number compared to the WT under both low N and high N fertilizer condition. More interestingly, osnlp3 mutants shows significantly shorter root length compared to the wild type under low phosphate condition. Our study demonstrate that OsNLP3 is a key regulator of N transport and utilization, and may also participate in the fine tuning of nitrate and phosphate availability. Therefore, OsNLP3 could be a potential target for genetic breeding of high NUE rice cultivars in the future.