Overexpression of Glycerol-3-Phosphate Acyltransferase from Suaeda salsa Improves Salt Tolerance in Arabidopsis

Abstract

Glycerol-3-phosphate acyltransferase is the first acyl esterifying enzyme in phosphatidylglycerol (PG) synthesis process. In this study, we isolated and characterized the glycerol-3-phosphate acyltransferase (GPAT) gene from Suaeda salsa (S. salsa) and obtained the full length of the GPAT gene from S. salsa (SsGPAT) by 5′ and 3′ RACE. The clone contained an open reading frame (ORF) of 1167 bp nucleotides that comprised of 388 amino acid residues. Real-time PCR revealed that the mRNA accumulation of GPAT in S. salsa was induced by salt stress. The highest expression levels were observed when S. salsa leaves were exposed to 300 mM NaCl treatment. At the germination stage, the germination rate and root length of overexpressed Arabidopsis strains were significantly higher than WT under different concentrations of NaCl treatments, while the inhibitory effect was significantly severe in T-DNA insertion mutant strains. In the seedling stage, chlorophyll content, the photochemical efficiency of PSII, PSI oxidoreductive activity (ΔI/Io), and the unsaturated fatty acid content of PG decreased less in overexpressed strains and more in mutant strains than that in WT under salt stress. These results suggest that the overexpression of SsGPAT in Arabidopsis enhances salt tolerance and alleviates the photoinhibition of PSII and PSI under salt stress by improving the unsaturated fatty acid content of PG.

Plant sn‐Glycerol‐3‐Phosphate Acyltransferases: Biocatalysts Involved in the Biosynthesis of Intracellular and Extracellular Lipids

“…Unfortunately, sequence information regarding the SsGPAT gene is not currently available, and therefore, it is unknown where this gene falls phylogenetically. The reduced level of salt tolerance was also reported for Atgpat2 and Atgpat6 mutants in the same study but the mechanism of these two GPATs’ contribution to salt tolerance has yet to be fully characterized (Sui et al, ). Moreover, though a role in stress response (chilling tolerance) has been well documented for plastidial GPAT, as previously discussed, very little is currently known regarding the function of other GPAT in this context.…”

“…However, unlike AtGPAT1 , both AtGPAT2 and AtGPAT3 have been found to be expressed at low levels in a rather broad range of plant tissues (including roots, seedlings, leave stem, flower, and siliques) (Beisson et al, ; Suh, Samuels, & Jetter, ; Yang et al, ; Zheng et al, ). Moreover, GPAT2 activity may be induced in some plant tissues through external stimuli such as salt stress (Sui, Tian, Wang, Wang, & Fan, ; Zheng et al, ). Intriguingly, a recent study of the rice OsGPAT3 , which is a closely related homolog of AtGPAT3 , demonstrated that in a similar manner to AtGPAT1 , this gene plays a crucial role in male fertility through its function in anther development and pollen formation (Men et al, ).…”

“…Although plant GPAT tend to be classified based on their subcellular locations and functions, several plant and algal GPAT are not so easily categorized. For instance, overexpression of a GPAT from the halophyte Suaeda salsa ( SsGPAT ) in Arabidopsis resulted in an enhancement of salt tolerance, possibly through the alleviation of the photoinhibition of PSII and PSI under salt stress by elevating the unsaturated fatty‐acid content (Sui et al, ). Unfortunately, sequence information regarding the SsGPAT gene is not currently available, and therefore, it is unknown where this gene falls phylogenetically.…”

Molecular mechanisms underlying stress response and adaptation

“…Similar to the effects of NO in cotton, exogenous hydrogen sulfide production enhances salt tolerance by decreasing Na + content in wheat seedlings . During salt acclimation in Arabidopsis thaliana , cell wall remodeling, ethylene biosynthesis, and signaling pathways play crucial roles . K + and Ca 2+ homeostasis are also important .…”

Environmental pollutants damage airway epithelial cell cilia: Implications for the prevention of obstructive lung diseases

“…Cilia can be typically divided into primary nonmotile cilia and motile cilia, depending on the axoneme structure. The axoneme of primary cilia is arranged in a ring of nine peripheral doublet microtubules (termed a 9 + 0 axoneme), and the axoneme of a motile cilium has two single microtubules at the center of the nine peripheral doublet ring (termed a 9 + 2 axoneme) . In addition, the peripheral doublets of motile cilia are attached by inner and outer dynein arms, which allow ciliary movement by ATP‐dependent conformational alterations.…”