IC4R010-Metabolomics-2015-25578272

Project Title

Rice (Oryza sativa) is an excellent resource; it comprises 25% of the total caloric intake of the world’s population, and rice plants yield many types of bioactive compounds. To determine the number of metabolites in rice and their chemical diversity, the metabolite composition of cultivated rice has been investigated with analytical techniques such as mass spectrometry (MS) and/or nuclear magnetic resonance spectroscopy and rice metabolite databases have been constructed. This review summarizes current knowledge on metabolites in rice including sugars, amino and organic acids, aromatic compounds, and phytohormones detected by gas chromatography–MS, liquid chromatography–MS, and capillary electrophoresis–MS.

According to Seaver et al. (2012), a comparison of individual metabolic databases revealed clear differences in the stored compounds (Seaver et al., 2012). When the researchers compared metabolite IDs used in the RiceCyc (Jaiswal et al., 2006), OryzaCyc, and AraCyc in Plant Metabolic Network (Figure 1), they found more than 1000 metabolites (e.g., primary metabolites) in these three databases. On the other hand, there were 54 metabolites in the two metabolic databases of rice. Of these, oryzalexins (Akatsuka et al., 1985; Kato et al., 1993; Kato et al., 1994) and momilactones (Kato-Noguchi and Peters, 2013) are known to be specific metabolites produced in rice.

Figure 1. Metabolites Found in RiceCyc and OryzaCyc, but Not in AraCyc.

RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa 230-0045, Japan
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Chiba 260-8675, Japan

Miyako Kusano (miyako.kusano@riken.jp) & Kazuki Saito (kazuki.saito@riken.jp)