Transcriptomic Profiling of RNAi-mediated Knockdown Rice for ACT Domain Repeat Protein 9 (OsACR9) as a Candidate for Glutamine Sensor

Abstract

In rice plants, glutamine (Gln) regulates expression of several key genes in nitrogen metabolism including NADH-glutamate synthetase 1 (NADH-GOGAT1) gene. However, little is known about molecular mechanisms for Gln-sensing and signaling systems in plants. To understand the Gln-sensing and signaling mechanisms, we have focused on rice ACT domain repeat proteins (OsACRs; encoded by OsACR1 to OsACR9) as a candidate for the Gln-sensor. We reported that cellular distribution of OsACR9 protein overlapped with NADH-GOGAT1 in various organs of rice. In the unexpanded leaf blades of tillers of RNAi-mediated OsACR9-knockdown rice transformants at T0 generation, there was a decrease in NADH-GOGAT1 mRNA content compared with that in the control. Involvement of OsACR9 in gene regulation will be discussed based on transcriptomic profile from the T1 plants.