Salinity induces membrane structure and lipid changes in maize mesophyll and bundle sheath chloroplasts

Abstract

The membranes of Zea mays (maize) mesophyll cell (MC) chloroplasts are more vulnerable to salinity stress than are those of bundle sheath cell (BSC) chloroplasts. To clarify the mechanism underlying this difference in salt sensitivity, we monitored changes in the glycerolipid and fatty acid compositions of both types of chloroplast upon exposure to salinity stress. The monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) contents were higher in MC chloroplasts than in BSC chloroplasts, in both the presence and absence of salt treatment. Under salt conditions, the MGDG level in MC chloroplasts was significantly lower than under normal conditions, while it was unchanged in BSC chloroplasts. In both types of chloroplast, the contents of DGDG, phosphatidylglycerol and phosphatidylinositol remained at the same levels in control and salt-treated plants, whereas sulfoquinovosyldiacylglycerol and phosphatidylcholine were significantly lower and higher, respectively, upon salt treatment. In addition, the fatty acid composition and double bond index of individual lipid classes were changed by salt treatment in both BSC and MC chloroplasts, although these factors had no effect on glycerolipid content. These findings suggest that the difference in salt sensitivity of MC and BSC chloroplast membranes is related to differences in MGDG responses to salinity. Thus, we propose that the low MGDG content and the low sensitivity of MGDG to salinity in BSC chloroplasts render them more tolerant than MC chloroplasts to salinity stress.

An Advanced Lipid Metabolism System Revealed by Transcriptomic and Lipidomic Analyses Plays a Central Role in Peanut Cold Tolerance

“…The reduction in MGDG is a common plant response to osmotic stress caused by freezing, drought, or salinity (Gigon et al, 2004;Chen and Thelen, 2013;Omoto et al, 2016), which could result in serious disorder and dysfunction of photosynthetic membranes (Garab et al, 2016). While the decreased MGDG was accompanied by the increased DGDG and SQDG in NH5 because of the upregulated expression of DGD1 and SQD2.…”

Up‐regulation of lipid metabolism and glycine betaine synthesis are associated with choline‐induced salt tolerance in halophytic seashore paspalum

“…DGDG and MGDG are the most abundant glycolipid species in the thylakoid membranes of chloroplasts and regulate the supramolecular structure of PS II complexes (Omoto et al, 2016). Decreased glycolipid content has been associated with a decline in chlorophyll content and photosynthetic activities (Dörmann & Benning, 2002).…”

“…Seed priming with choline has been reported to alter phospholipid content of wheat plants, which may affect tolerance (Salama & Mansour, 2015). Lipid reprogramming in terms of changes in lipid content, composition, and saturation levels could facilitate membrane stabilisation and salt tolerance (Omoto, Iwasaki, Miyake, & Taniguchi, 2016). Whether and how choline affects phospholipids and glycolipids involved in regulating salt tolerance have not been studied.…”

Melatonin-Stimulated Triacylglycerol Breakdown and Energy Turnover under Salinity Stress Contributes to the Maintenance of Plasma Membrane H+–ATPase Activity and K+/Na+ Homeostasis in Sweet Potato

“…The critical role of lipid remodeling in plant salt tolerance comes from the fact that lipids have a great impact not only on changing the membrane integrity, permeability and fluidity but also on modulating membrane proteins activity and cellular signaling pathway ( Mansour et al, 2015 ). Lipidomic analysis of maize ( Zea mays ) mesophyll cell (MC) and bundle sheath cell (BSC) chloroplasts revealed a less reduction of MGDG content in salt-stressed BSC chloroplasts; this property maintained the stabilization of thylakoid membranes and rendered BSC chloroplasts more tolerant to salinity stress than MC chloroplasts ( Omoto et al, 2016 ). PA production catalyzed by phospholipase D (PLD) under salinity condition is required to phosphorylate MPK6 and subsequent activation of PM Na + /H + antiporter (SOS1) and Na + extrusion in Arabidopsis ( Yu et al, 2010 ).…”