LC-ESI-MS/MS Analysis of Sulfolipids and Galactolipids in Green and Red Lettuce (Lactuca sativa L.) as Influenced by Sulfur Nutrition

Abstract

Sulfur (S) deprivation leads to abiotic stress in plants. This can have a significant impact on membrane lipids, illustrated by a change in either the lipid class and/or the fatty acid distribution. Three different levels of S (deprivation, adequate, and excess) in the form of potassium sulfate were used to identify individual thylakoid membrane lipids, which might act as markers in S nutrition (especially under stress conditions). The thylakoid membrane consists of the three glycolipid classes: monogalactosyl- (MGDG), digalactosyl- (DGDG), and sulfoquinovosyl diacylglycerols (SQDG). All of them have two fatty acids linked, differing in chain length and degree of saturation. LC-ESI-MS/MS served as a powerful method to identify trends in the change in individual lipids and to understand strategies of the plant responding to stress. Being a good model plant, but also one of the most important fresh-cut vegetables in the world, lettuce (Lactuca sativa L.) has already been shown to respond significantly to different states of sulfur supply. The results showed a transformation of the glycolipids in lettuce plants and trends towards a higher degree of saturation of the lipids and an increased level of oxidized SQDG under S-limiting conditions. Changes in individual MGDG, DGDG, and oxidized SQDG were associated to S-related stress for the first time. Promisingly, oxidized SQDG might even serve as markers for further abiotic stress factors.

Unravelling the biostimulant activity of a protein hydrolysate in lettuce plants under optimal and low N availability: a multi‐omics approach

“…In the case of PH2 fraction, an enhanced lipid profile mediated by the accumulation of glycolipids and polyunsaturated fatty acids was reported. Recent reports highlight the implication of membrane‐associated lipids remodelling under nutrient stress in different lettuce cultivars to contribute to enhancing photosynthetic performance and plant growth (Körber et al 2023). Finally, in the case of PH3 fraction‐treated lettuce plants under stress, an accumulation of vitamin B2 and folate pathway intermediaries was observed.…”