ScienceDaily (Feb. 8, 2012) — A large-scale study analyzing metabolic compounds in rice grains conducted by researchers at the RIKEN Plant Science Center (PSC) and their collaborators has identified 131 rice metabolites and clarified the genetic and environmental factors that influence their production

At the heart of this challenge are so-called quantitative train loci (QTL), stretches of DNA which contain or link to the genes for a phenotypic trait, in this case metabolite levels. To breed lines of rice which produce more of a specific metabolite (for example one that boosts its nutritional value), you have to know which DNA regions are involved and in what role. This is hard because metabolite levels are controlled by many different QTLs and also strongly influenced by the environment.

To solve this problem, researchers at the PSC teamed up with their collaborators at the National Institute of Agrobiological Science (NIAS) to analyze rice grain metabolomic QTL (mQTL) using state-of-the-art mass spectroscopy pipelines developed at the PSC. Analysis of 85 experimental lines of rice specially bred for QTL analysis, prepared by the NIAS researchers and harvested in 2005 and 2007, yielded a total of 759 metabolite signals. From these, the team identified 131 metabolites, including amino acids, lipids, and flavonoids, and identified a total of 801 mQTLs around the rice genome.

Most important of all, the team showed that while the levels of most metabolites they identified are influenced mainly by environmental factors, genetics can sometimes play a stronger role: coordinated control of amino acids was linked to an mQTL “hotspot” on chromosome 3, while variation of flavenoid levels was linked to genetic factors. Published in The Plant Journal, the

Journal Reference:

1. Fumio Matsuda, Yozo Okazaki, Akira Oikawa, Miyako Kusano, Ryo Nakabayashi, Jun Kikuchi, Jun-Ichi Yonemaru, Kaworu Ebana, Masahiro Yano, Kazuki Saito. Dissection of genotype-phenotype associations in rice grains using metabolome quantitative trait loci analysis. The Plant Journal, 2012; DOI: 10.1111/j.1365-313X.2012.04903.x

Source : SCienceDaily