Metabolite Profiling of Germinating Rice Seeds

Abstract

A metabolite profiling approach based on gas chromatography-mass spectrometry (GC-MS) was used to investigate time-dependent metabolic changes in the course of the germination of rice. Brown rice kernels were soaked and incubated for a total of 96 h under ambient conditions. Samples taken during the germination process were subjected to an extraction and fractionation procedure covering a broad spectrum of lipophilic (e.g., fatty acid methyl esters, hydrocarbons, fatty alcohols, sterols) and hydrophilic (e.g., sugars, acids, amino acids, amines) low molecular weight rice constituents. Investigation of the obtained fractions by GC resulted in the detection of 615 distinct peaks, of which 174 were identified by means of MS. Statistical assessment of the data via principal component analysis demonstrated that the metabolic changes during the germination process are reflected by time-dependent shifts of the scores, which were similar for the three rice materials investigated. Analysis of the corresponding loadings showed that polar metabolites were major contributors to the separation along the first principal component. Relative quantifications based on standardized peak heights revealed dynamic changes of the metabolites in the course of the germination.

Differentiation of Four Varieties of Germinating Thai Colored Indica Rice (<i>Oryza sativa</i> L.) by Metabolite Profiling

“…The growth of seeds is accompanied by monocotyledonous morphological developments involving the initial enlargement of the rice embryos and the subsequent formations of shoots and roots. This phenomenon is in agreement with the germination progress previously described for brown rice (Shu et al 2008). The developmental changes upon sprouting process of non-colored, red, purple, and black Thai indica rice samples were comparable.…”

“…GC-based metabolite profiling techniques were also applied to follow the natural development of plant-derived food, for example, the metabolic changes in the course of germination of rice (Shu et al 2008), potato , barley and mung beans (Na Jom et al 2011), among which germinated rice has commonly received great attention (Wu et al 2013).…”

Spatial Mapping and Profiling of Metabolite Distributions during Germination

“…Because of the agricultural importance of cereal grains, previous metabolomics-based work has focused on these processes during the germination of rice (Oryza sativa; Shu et al, 2008) and the malting process for barley (Hordeum vulgare;Frank et al, 2011). However, traditional metabolomics analyses often prove laborious and challenging, with limited spatial information.…”

“…Many of the metabolic pathways that are induced during the seed germination processes that involve starch, oil, and protein turnover have been studied via molecular, genetic, and biochemical studies (Ingle et al, 1964;Limami et al, 2002;Shu et al, 2008;Zhang et al, 2009). Therefore, techniques that allow for the determination of the spatial localization of metabolites in fine detail, specifically mass spectrometry imaging (MSI), should allow for further insight into the mechanisms and actions of the pathways that are integral to seed germination.…”

Profiling and Association Mapping of Grain Metabolites in a Subset of the Core Collection of Chinese Rice Germplasm (Oryza sativaL.)

“…7À9 As a useful metabolic tool, GC-MS coupled with multivariate analysis was widely used in nontargeted tests of metabolites in different rice germplasms. 10,11 However, no study has reported an investigation of the metabolic diversity in a large germplasm set and linked metabolite contents with DNA markers by association mapping.…”