An efficient and comprehensive plant glycerolipids analysis approach based on high-performance liquid chromatography-quadrupole time-of-flight mass spectrometer.

Shaoping Lu,Qing Li,Hongbo Liu,Cheng Jin,Liang Guo

doi:10.1002/pld3.183

Abstract

In past two decades, numerous lipidomics approaches based on mass spectrometry with or without liquid chromatography separation have been established for identification and quantification of lipids in plants. In this study, we developed an efficient and comprehensive lipidomics approach based on UPLC with an Acquity UPLCTM BEH C18 column coupled to TripleTOF using ESI in positive ion mode and MS/MSALL scan for data collection. Lipid extract was prepared to 2 mg/ml solution according to dry tissue weight and mixed with 13 kinds of internal standards including PA, PC, PE, and PG. Each analysis required single injection of 5–10 μl lipid solvent and completed in 32 min. A target method dataset was generated using the LipidView software for prediction of the accurate mass of target lipid species. The dataset was uploaded into the PeakView to create processing datasets to search target lipid species, which achieved batch data processing of multiple samples for lipid species‐specific identification and quantification. As proof of concept, we profiled the lipids of different tissues of rapeseed. Thirteen lipid classes including 218 glycerolipids were identified including 46 TAGs, 15 DAGs, 20 PCs, 24 PEs, 13 PGs, 14 PIs, 26 PSs, 12 PAs, 16 MGDGs, 16 DGDGs, 6 LysoPCs, 5 LysoPEs, and 5 LysoPGs. Together, our approach permits the analysis of glycerolipids in plant tissues with simplicity in sample analysis and data processing using UPLC‐TripleTOF.

Highlights

Lipids are essential components of cell membranes
The analysis platform of the mass spectrometry represented by electrospray ioni‐ zation (ESI)‐ MS/MS is widely used in the composition analysis of various biologi‐ cal tissue extracts (Bilgin et al, 2016; Cheong et al, 2014; Dennis, 2009; Han & Gross, 2005; Han et al, 2006; Horn & Chapman, 2012; Merrill, Sullards, Allegood, Kelly, & Wang, 2005; Shiva et al, 2013; Welti et al, 2002)
Methods using neutral loss/precursor scan or multiple reaction monitoring (MRM) data collection are favored in the analysis of lipidome for their excellent performance in reliability and sensitivity (Gao et al, 2016; Simons et al, 2012)

Summary

| INTRODUCTION

Lipids are essential components of cell membranes. Changes in lipids lead to the alterations of the fluidity (Dawaliby et al, 2016; Nguyen, Rudge, Zhang, & Wakelam, 2017), permeability (Colombini, 2017; Van der Paal, Neyts, Verlackt, & Bogaerts, 2016), and polarity (Hammond & Hong, 2018; Tejos et al, 2014) of the cell membrane. A direct infu‐ sion approach ( called shotgun lipidomics) based on electrospray ionization mass spectrometry (ESI‐MS/MS) using precursor, and neutral loss scan mode was developed by Welti et al (2002) which has been widely used in plant lipids analysis (Devaiah et al, 2006; Han, Yang, Yang, Cheng, & Gross, 2006; Welti et al, 2002; Welti, Wang, & Williams, 2003). After data collection by high‐resolution mass spectrometers, lipid analysis is usually car‐ ried out by searching against database which typically generates false‐positive results which require expertise for manual correc‐ tion (Gao et al, 2016; Godzien et al, 2015) These ap‐ proaches usually failed to comprehensively identify lipid species in each lipid class (Zheng et al, 2017). We employed this approach to com‐ prehensively analyze the glycerolipids from crude lipid extracts of rapeseed tissues in order to facilitate the understanding and study of lipid metabolism in rapeseed

| MATERIALS AND METHODS

| DISCUSSION

CONFLICT OF INTEREST