Dynamic changes in membrane lipid composition of leaves of winter wheat seedlings in response to PEG-induced water stress

Abstract

Background: Membrane lipid composition associates closely with membrane stability and fluidity under water stress. In this study, lipidomic analyses based on electrospray ionization mass spectrometry (ESI-MS/MS) were carried out to explore dynamic changes of membrane lipids in term of molecular species caused by PEG (Polyethylene glycol-6000)-induced water stress in wheat seedlings. Results: Among the main phospholipids, phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG) are primary degradation targets, and PC was degraded in the largest degree. Membrane ion leakage dramatically increased later than the significant reduction of these phospholipids, indicating that the loss of membrane integrity lagged behind severe phospholipid degradation. Monogalactosyldiacylglycerol (MGDG) increased firstly and decreased later, while digalactosyldiacylglycerol (DGDG) ratcheted up with stress. DGDG/MGDG increased after stress for 3 days, and unsaturation of DGDG was promoted with stress. Variation trends of galactolipids differed among molecular species. The time when MGDG (34:3), DGDG (34:3) began to decline approached to the time when non-stomatal limitation impaired photosynthesis. While the two predominant molecular species MGDG (36:6) and DGDG (36:6) began to decline later. So we speculated that MGDG (34:3), DGDG (34:3) might be key components in photosynthesis apparatus and participate in photosynthesis directly. While the two predominant molecular species, MGDG (36:6) and DGDG (36:6) might locate in thylakoid lipid bilayer matrix and play roles in stabilizing the membrane. The research provides new insights into the dynamic response of lipid metabolism to PEG-induced water stress. Conclusion: In wheat plants under water stress, the major molecular species of PC, PE and PG were degraded, MGDG and DGDG molecular species had differing degradation time courses.

Lipid Compositions and Geographical Discrimination of 94 Geographically Authentic Wheat Samples Based on UPLC-MS with Non-Targeted Lipidomic Approach

“…In addition, greater MGDG (18:2/16:0) abundance was found in Fujian wheat samples while compared with that from Gansu, which might due to the rainfall differences between two provinces according to the previous study that changes of wheat lipid constitutions happened under water shortage treatment [56]. Further, the observed increasing ratio of DGDG and MGDG might be due to the cylindrical shape of DGDG with two galactosyls, which contributed to the formation of a stable bilayer phase while MGDG tended to form an unstable hexagonal phase [10].…”

“…Further, the observed increasing ratio of DGDG and MGDG might be due to the cylindrical shape of DGDG with two galactosyls, which contributed to the formation of a stable bilayer phase while MGDG tended to form an unstable hexagonal phase [10]. These phenomenon might explain the fact that wheat samples from northern provinces in China, which might suffer the water absence induced lower MGDG amount to maintain the stable bilayer membrane structure when compared with wheat samples from southern provinces of China [56].…”

Fatty acid composition of corn and wheat plant shoots under the action of sali­­cy­late in drought conditions

“…In fact, cellular mem branes are the main targets of degradation processes caused by the lack of moisture. It has been shown that drought reduces the level of membrane lipids [7,31,34] by inhibiting their biosynthesis [7,8], and, on the other hand, by activating lipolytic and peroxida tive activity [10,26].…”

Doubled haploids of interspecific hybrids between Brassica napus and Brassica rapa for canola production with valuable breeding traits

“…Using of PEG is one of the appropriate procedures to create drought conditions for screening some parameters of drought tolerance, such as germination, plant height, root length, relative water content (RWC) (Basha et al, 2015). Some authors confirm that simulating drought using PEG in plants consists in influencing the lipid composition of membranes, which is a key component in photosynthesis (Wang et al, 2020), and also leads to some changes in the structure of chloroplasts ( Khan et al, 2019). Using PEG-6000 to simulate drought is a very simple and fast method for early detection of drought tolerance (Xie et al, 2013).…”