Research on the dynamics of photosynthate distribution between chloroplast and cytosol

在比较水稻和大豆初级光合作用的行为时，初级光合作用产物大量分配到淀粉组分中，特别是在大豆中。由于水稻和大豆在光合作用、糖酵解、TCA循环等方面的代谢途径是相同的，因此观察到的差异可能来自于同化化合物池的不同大小。为了证实这一观点，我们研究了几个影响代谢产物分配的基因在不同生长阶段的表达情况。所得结果支持光合作用产物的分布规律。初级磷合成物在淀粉组分中的大量分布表明了胞浆、叶绿体和液泡之间输送系统的重要性，因此开发了一种新的方法来分离这些细胞器，而不需要在提取过程中进行进一步的酶反应。开发了非水相分离方法，并将其应用于大豆叶的分离。用气相色谱-质谱仪(GC-MS)对各组分进行代谢组学分析。代谢组学方法使我们能够识别和量化组织中的大约130种化合物。

When comparing the behavior of primary photosynthate between rice and soybean, a large amount of primary photosynthate is distributed to starch fraction especially in soybean. As the metabolic pathway regarding photosynthesis, glycolysis, TCA cycle, etc. are same between rice and soybean, the observed difference is assumed to be derived from the different size of the pool of assimilated compounds. To confirm the idea, several genes' expression which are working on metabolites partitioning are investigated at different growth stage. The obtained results support the photosynthate distribution pattern. A large distribution of primary phosynhtate into starch fraction indicate the importance of delivery system among cytosol, chloroplast, and vacuole, thus a new method is developed to separate these organelle without further enzyme reaction during extraction process. Non aqueous fractionation method was developed and applied to soybean leaf. Each fraction was further analyzed by metabolomics approach using gas chromatography mass spectrometry (GC-MS). The metabolomics approach allows us to identify and quantify about 130 compounds in the tissue.