Quantitative Profiling of Arabidopsis Polar Glycerolipids under Two Types of Heat Stress

Abstract

At the cellular level, the remodelling of membrane lipids and production of heat shock proteins are the two main strategies whereby plants survive heat stress. Although many studies related to glycerolipids and HSPs under heat stress have been reported separately, detailed alterations of glycerolipids and the role of HSPs in the alterations of glycerolipids still need to be revealed. In this study, we profiled the glycerolipids of wild-type Arabidopsis and its HSP101-deficient mutant hot-1 under two types of heat stress. Our results demonstrated that the alterations of glycerolipids were very similar in wild-type Arabidopsis and hot-1 during heat stress. Although heat acclimation led to a slight decrease of glycerolipids, the decrease of glycerolipids in plants without heat acclimation is more severe under heat shock. The contents of 36:x monogalactosyl diacylglycerol (MGDG) were slightly increased, whereas that of 34:6 MGDG and 34:4 phosphatidylglycerol (PG) were severely decreased during moderate heat stress. Our findings suggested that heat acclimation could reduce the degradation of glycerolipids under heat shock. Synthesis of glycerolipids through the prokaryotic pathway was severely suppressed, whereas that through the eukaryotic pathway was slightly enhanced during moderate heat stress. In addition, HSP101 has a minor effect on the alterations of glycerolipids under heat stress.

Leaf Lipid Alterations in Response to Heat Stress of Arabidopsis thaliana

“…Neither of the two heating treatments caused leaf death, and the plants exhibited no detectable wilting 24 h after the heat treatment ( Figure S1 ). A recent paper also found that wild-type Arabidopsis survived treatments of 45 °C and 38 °C, followed by 45 °C, albeit for shorter time periods [ 14 ]. Measurements of ion leakage on six plants at each time point (others not measured) did not indicate an increase in ion leakage due to the heat treatment, as would have been expected if the heat treatment caused cell lysis ( Table S1 ).…”

LPEATs Tailor Plant Phospholipid Composition through Adjusting Substrate Preferences to Temperature

“…Studies conducted on A. thaliana showed that leaf membrane lipid composition was characterized by a decrease in levels of 18:3 and 16:3, and elevated levels of 16:0 and 18:1. Leaf tissue exposed to heat stress also possessed higher amounts of 18:2, in contrast to the seeds [ 34 , 35 , 36 , 37 ]. In our study, similar preference towards 18:2-CoA was observed in case of LPEAT enzymes present in vegetative organs.…”

“…On the contrary, heat-stressed plants exhibited significantly reduced levels of PE and reduced amounts of 18:3. Furthermore, amounts of oleic acid increased in all molecular species [ 37 ]. The possible changes of PE composition are consistent with LPEATs preferences, which may play a dominant role in their regulation, especially its affinity towards 18:1-CoA and 18:3-CoA at various temperatures.…”

Mechanisms and functions of membrane lipid remodeling in plants

“…In general, organisms increase acyl desaturation at lower temperatures while decreasing it at higher temperatures to counteract the effects of temperature variations on membrane fluidity (Ernst et al ., 2016). This phenomenon has been demonstrated in many studies (Chen et al ., 2006; Falcone et al ., 2004; Hugly et al ., 1989; Hugly and Somerville, 1992; Kunst et al ., 1989a; Qin et al ., 2020; Wada et al ., 1990; Welti et al ., 2002). A similar link between the degree of acyl desaturation and plant stress tolerance has been reported for plants under drought and salt conditions (Gigon et al ., 2004; Li et al ., 2014; Liu et al ., 2013; Sui and Han, 2014; Sui et al ., 2018; Zhang et al ., 2005).…”

“…They found that low temperature enhanced the plastid pathway of galactolipid biosynthesis and conversely, high temperature enhanced the ER pathway. Consistent with these observations, a recent study found that the synthesis of glycerolipids via the plastid pathway was severely compromised, whereas lipid assembly via the ER pathway was slightly enhanced, during moderate heat stress (Qin et al ., 2020). Moreover, higher temperature caused an increase in the transport of DAG moieties with C16/C18 from the ER to the chloroplast for MGDG and DGDG biosynthesis at the expense of DAG moieties with C18/C18, while lower temperature resulted in the opposite (Li et al ., 2015).…”