GC-MS based metabolomics study of the resurrection plant Ramonda serbica

Abstract

Ramonda serbica represents the remnant of the Tertiary tropical and subtropical flora in Europe and is the rare resurrection plants of Northern Hemisphere temperate zone. The plant remains well-hydrated during spring, late autumn and in winter. In summer and early autumn when plants are subjected to drought, their desiccation tolerance comes into operation and they spend it in anabiosis [1]. In this study, metabolic responses to dehydration and rehydration of R. serbica, were investigated. For this purpose, GC-MS/FID based metabolomics method was performed. Leaves from the control (well-watered), dehydrated and partially rehydrated plants were sampled. Each leaf was powdered using liquid nitrogen and then freeze-dried. The internal standard (10-undecenoic acid) was added to the dry plant material and then extracted in methanol/water using ultra-sonication. After centrifugation of the mixture, the supernatant was dried and derivatized using two-step procedure involving oximation and silylation. GC-MS/FID analysis of each sample was then performed. The metabolites were identified using El-MS spectra. The areas from FID chromatograms were used for multivariate data analysis. Two OPLS-DA models were applied to investigate dehydration and rehydration process. According to high VIP scores, sugars, such as fructose, glucose, galactinol, sucrose, together with glyceric acid, xylonic acid 8-lactone and aspartic acid were found to be the most influential in the OPLS-DA models.