Study On Lipidomics Of Different Germplasm Camellia Oleifera Seeds Based On LC-MS/MS Technology

Camellia oleifera is an important woody oil tree species in China,which is mainly distributed in the south of China.It is recognized as one of the four woody oil tree species in the world together with oil palm,olive and coconut.Camellia oleifera oil is recognized high-quality edible oil.It contains unsaturated fatty acids such as oleic acid and linoleic acid,with a content of more than 90%.Due to the great development potential of Camellia oleifera,the study of Camellia oleifera metabolomics and then clarify the lipids metabolism pathway of Camellia oleifera has also become the key research direction of scientists.However,there are few comparative studies on the lipidomics of different Camellia oleifera,and the analysis of different germplasm Camellia oleifera mainly focuses on the physiological and biochemical characteristics and transcriptome.In this study,the lipids of mature Camellia oleifera kernel of different germplasm were compared and a nalyzed by non-targeted LC-MS/MS technology,and three representatives Camellia oleifera varieties were selected for comparative analysis of lip idomics.The main results were as follows:Through the extraction of small molecular metabolites from the seed of Camellia oleifera collected from different germplasm,lip idomics was studied by LC-MS/MS technology,and the data were collected by positive and negative ion mode.A total of1329 lipid compounds were identified,which can be divided into six categories,104 FAs,547 GLs,345 GPs,286 SPs,27 STs and 20 PRs.Among these six categories,GLs accounts for the largest proportion,accounting for 41%,followed by GPs accounting for 26%,SPs accounting for 22%,FAs accounting for 8%,STs accounting for 2% and PRs accounting for 1%.A total of 99 lipid compounds with significant differences were screened from XL1 and XL210 samples according to the conditions of VIP > 1 and P value < 0.05.Among them,59 lipids were down-regulated in XL210 and 40 lipids were up-regulated in XL1,but the differential metabolites were not enriched in the pathway.It is speculated that there were fewer significantly different lipid compounds enriched due to close genetic relationship,so they were not enriched in the same metabolic pathway.A total of 140 significantly different lipid compo unds were screened from CL3 and CL53 samples according to the conditions of VIP > 1 and P value < 0.05.By comparing CL3 and CL53,it was found that 79 significantly different lipid compounds in CL3 were significantly up-regulated and 61 significantly different lipid compounds were significantly down regulated.A total of 7 metabolic pathways were enriched,including glycerophospholipid metabolism,glycerolipid metabolism,glycosylphosphatidylinositol(GPI)-anchor biosynthesis,Linoleic acid metabolism,arachidonic acid metabolism,phosphatidylinositol signaling system and alpha-linolenic acid metabolism,in which glycerophospholipid metaboli sm pathway was the most important pathway.A total of 121 lipid compounds with significant differences were screened f rom HX and HS samples according to the conditions of VIP > 1 and P value < 0.05.By comparing HX and HS,it was found that 86 SDLs in HX were significantly up-regulated and 35 SDLs were significantly down regulated.Among the seven metabolism pathways enriched,the most relevant pathways were glycerophospholipid metabolism,glycerolipid metabolism,glycosylphosphatidylinositol(GPI)-anchor biosynthesis,Linoleic acid metabolism,arachidonic acid metabolism,phosphatidylinositol signaling system and alpha-linolenic acid metabolism has little pathway effect.The above results provide a theoretical basis for further study on the molecular mechanism of oil metabolism and molecular breeding of Camellia oleifera with high oil contents.