Alanine aminotransferase (OsAlaAT1) modulates nitrogen utilization, grain yield, and quality in rice

Since the widespread use of inorganic nitrogen fertilizers has greatly contributed to rice yields, but it has also caused serious environmental problems. Therefore, the identification and study of genes involved in regulating nitrogen use efficiency (NUE) in rice is a practical way to improve grain yield and alleviate environmental problems caused by the flood of nitrogen fertilizer. Here, we identified a low nitrogen use efficiency rice mutant lnue1 which showed shorter plants, reduced yield traits, bad rice quality. And the NUE was significantly reduced; the nitrogen concentration in lnue1 tissues was higher than that of the wild-type. Map-based cloning showed that LNUE1 encode an alanine aminotransferase (OsAlaAT1). The enzymatic activity of AlaAT in lnue1 was sharply reduced. Overexpression of LNUE1 could improve rice yield potential. Altogether, our results demonstrated that LNUE1 is a key factor to regulate the NUE, then influences the grains yield and the quality in rice simultaneously, and denote new insights into how to increase the rice NUE, which would be useful for genetic improvement of high yield and grain quality.