The role of glycolipids at the interface of plant-microbe interactions during nodulation and myorrhiza formation in Lotus japonicus

糖脂是植物和微生物之间的膜的组成部分。我们正在研究的作用，半乳糖甘油酯，甾醇葡萄糖苷和葡萄糖神经酰胺的共生相互作用的莲花植物与中生根瘤菌在acerulation或真菌球囊霉在菌根形成。由于每种糖脂类别均由许多分子种类组成，因此开发了基于四极杆-飞行时间质谱（Q-TOF MS）的方法来测量糖甘油脂、固醇脂质和鞘脂。这包括首次开发用于测量植物中所有甾醇脂质类（游离甾醇、甾醇糖苷、甾醇酯、酰化甾醇糖苷）的方法。在前一个资助期内，产生了携带参与糖脂合成的基因（DGD 1，DGD 2，SGT 1，SGT 2，GCS）的RNAi构建体的转基因Lotus植物。通过Q-TOF MS进行的脂质测量显示，固醇葡糖苷和葡糖神经酰胺分别在SGT 2和GCS RNAi系中减少。我们获得了莲花基因DGD 1、DGD 2、SGT 2和GCS的TILLING突变体。转基因RNAi系和突变系的结瘤和菌根化实验正在进行中。此外，我们开发了一种非靶向的Q-TOF MS方法，我们将采用该方法来搜索莲花中响应于真菌化或真菌化的脂质。

Glycolipids are constituents of membranes at the boundary between plants and microorganisms. We are studying the role of galactoglycerolipids, sterol glucosides and glucosylceramides in the symbiotic interaction of Lotus japonicus plants with Mesorhizobium during nodulation or with the fungus Glomus during mycorrhiza formation. Because each glycolipid class consists of numerous molecular species, a quadrupole-time of flight mass spectrometry (Q-TOF MS) based method was developed for the measurement of glycoglycerolipids, sterol lipids and sphingolipids. This includes the first development of a method for the measurement of all sterol lipid classes in plants (free sterols, sterol glucosides, sterol esters, acylated sterol glucosides). Transgenic Lotus plants carrying RNAi constructs for the genes involved in the synthesis of glycolipids (DGD1, DGD2, SGT1, SGT2, GCS) were generated during the previous funding period. Lipid measurements by Q-TOF MS revealed that sterol glucosides and glucosylceramides are reduced in SGT2 and GCS RNAi lines, respectively. We obtained TILLING mutants for the Lotus genes DGD1, DGD2, SGT2 and GCS. Nodulation and mycorrhization experiments of the transgenic RNAi lines and of the mutant lines are underway. Furthermore, we developed a non-targeted Q-TOF MS approach that we will employ to search for lipids responding to nodulation or mycorrhization in Lotus.