Differential regulation of two types of monogalactosyldiacylglycerol synthase in membrane lipid remodeling under phosphate-limited conditions in sesame plants.
Differential regulation of two types of monogalactosyldiacylglycerol synthase in membrane lipid remodeling under phosphate-limited conditions in sesame plants.
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DOI：
10.3389/fpls.2013.00469
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发表时间：
2013
影响因子：
5.6
通讯作者：
Ohta H
中科院分区：
文献类型：
--
作者：
Shimojima M;Watanabe T;Madoka Y;Koizumi R;Yamamoto MP;Masuda K;Yamada K;Masuda S;Ohta H
磷酸盐(PI)的限制会导致植物膜脂的剧烈重塑。糖脂代替降解的磷脂，从而提供必要的生物过程所需的等电点。高等植物中存在两种主要的膜脂重塑方式：一种是质体中磺基喹诺酮二酰甘油浓度的增加，以补偿磷脂酰甘油浓度的降低；另一种是质体中双半乳糖基甘油(DGDG)的合成，以及DGDG向质外膜的输出，以补偿磷脂丰度的减少。脂质重塑依赖于单半乳糖二酰甘油(MGDG)的充足供应，MGDG是一种底物，支持低PI利用率导致的DGDG合成速度加快。尽管编码MGDG合成酶的同源基因存在于从细菌到高等植物的光合作用有机体中，但MGDG合成的调控已经在模式植物拟南芥中得到了最广泛的分析。我们最近假设，在种子植物出现后，两种类型的MGDG合成酶发生了分歧。这种差异可能既使植物能够适应土壤中广泛的磷有效性，又有助于种子植物的多样性。在这里介绍的工作中，我们发现芝麻也发生了膜脂重塑，芝麻是亚洲最常见的传统作物之一。我们从芝麻中鉴定了两种类型的MGDG合成酶(由SeMGD1和SeMGD2编码)，并分析了它们的酶学性质。我们的结果表明，这两个基因都对应于拟南芥MGDG合成酶的A型和B型亚型。值得注意的是，虽然PI限制只上调了编码拟南芥B型异构体的基因，但低PI的可用性上调了SeMGD1和SeMGD2的表达。我们讨论了芝麻和拟南芥对低磷有效性的不同反应的意义。
Phosphate (Pi) limitation causes drastic lipid remodeling in plant membranes. Glycolipids substitute for the phospholipids that are degraded, thereby supplying Pi needed for essential biological processes. Two major types of remodeling of membrane lipids occur in higher plants: whereas one involves an increase in the concentration of sulfoquinovosyldiacylglycerol in plastids to compensate for a decreased concentration of phosphatidylglycerol, the other involves digalactosyldiacylglycerol (DGDG) synthesis in plastids and the export of DGDG to extraplastidial membranes to compensate for reduced abundances of phospholipids. Lipid remodeling depends on an adequate supply of monogalactosyldiacylglycerol (MGDG), which is a substrate that supports the elevated rate of DGDG synthesis that is induced by low Pi availability. Regulation of MGDG synthesis has been analyzed most extensively using the model plant Arabidopsis thaliana, although orthologous genes that encode putative MGDG synthases exist in photosynthetic organisms from bacteria to higher plants. We recently hypothesized that two types of MGDG synthase diverged after the appearance of seed plants. This divergence might have both enabled plants to adapt to a wide range of Pi availability in soils and contributed to the diversity of seed plants. In the work presented here, we found that membrane lipid remodeling also takes place in sesame, which is one of the most common traditional crops grown in Asia. We identified two types of MGDG synthase from sesame (encoded by SeMGD1 and SeMGD2) and analyzed their enzymatic properties. Our results show that both genes correspond to the Arabidopsis type-A and -B isoforms of MGDG synthase. Notably, whereas Pi limitation up-regulates only the gene encoding the type-B isoform of Arabidopsis, low Pi availability up-regulates the expression of both SeMGD1 and SeMGD2. We discuss the significance of the different responses to low Pi availability in sesame and Arabidopsis.
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DOI：
10.1073/pnas.100132197
发表时间：
2000-07-05
影响因子：
11.1
作者：
Jarvis, P;Dörmann, P;Chory, J
通讯作者：
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DOI：
10.1073/pnas.95.4.1950
发表时间：
1998-02-17
影响因子：
11.1
作者：
Essigmann, B;Güler, S;Benning, C
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影响因子：
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通讯作者：
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DOI：
10.1073/pnas.180320497
发表时间：
2000-09-12
影响因子：
11.1
作者：
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通讯作者：
Benning, C
影响因子：
2.9
作者：
Acevedo-Hernandez, Gustavo;Oropeza-Aburto, Araceli;Herrera-Estrella, Luis
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