Genome-wide analysis of the Glycerol-3-Phosphate Acyltransferase (GPAT) gene family reveals the evolution and diversification of plant GPATs

Abstract

sn-Glycerol-3-phosphate 1-O-acyltransferase (GPAT) is an important enzyme that catalyzes the transfer of an acyl group from acyl-CoA or acyl-ACP to the sn-1 or sn-2 position of sn-glycerol-3-phosphate (G3P) to generate lysophosphatidic acids (LPAs). The functional studies of GPAT in plants demonstrated its importance in controlling storage and membrane lipid. Identifying genes encoding GPAT in a variety of plant species is crucial to understand their involvement in different metabolic pathways and physiological functions. Here, we performed genome-wide and evolutionary analyses of GPATs in plants. GPAT genes were identified in all algae and plants studied. The phylogenetic analysis showed that these genes group into three main clades. While clades I (GPAT9) and II (soluble GPAT) include GPATs from algae and plants, clade III (GPAT1-8) includes GPATs specific from plants that are involved in the biosynthesis of cutin or suberin. Gene organization and the expression pattern of GPATs in plants corroborate with clade formation in the phylogeny, suggesting that the evolutionary patterns is reflected in their functionality. Overall, our results provide important insights into the evolution of the plant GPATs and allowed us to explore the evolutionary mechanism underlying the functional diversification among these genes.

Plant Unsaturated Fatty Acids: Biosynthesis and Regulation

“…The biosynthesis of C18 PUFAs being coupled to that of membrane lipids highlights the importance of GPAT. Composing a multigene family in planta, GPATs acylate the sn-1 or sn-2 position of G3P to form lysoPA, which is a common intermediate to membrane glycerolipids, storage TAGs, and extracellular polyesters (e.g., cutin) (Waschburger et al, 2018). In Arabidopsis, there are 10 GPAT genes designated ATS1 (or ACT1) and GPAT1-9.…”

“…Their products are distributed to three subcellular compartments (ATS1 to plastids, GPAT1-3 to mitochondria, and GPAT4-9 to the ER) to be involved in different metabolic pathways and biological functions (Chen et al, 2011;Sui et al, 2017;Jayawardhane et al, 2018). With respect to C18 PUFA generation, ATS1 and GPAT9, the two sn-1 regiospecific members, control the entries of the prokaryotic and eukaryotic pathways, respectively (Jayawardhane et al, 2018;Waschburger et al, 2018). Localized in the stroma, ATS1 is the only soluble GPAT member.…”

Characterization of glycerol-3-phosphate acyltransferase 9 (AhGPAT9) genes, their allelic polymorphism and association with oil content in peanut (Arachis hypogaea L.)

“…Studies have shown that GPAT9 exhibits no phosphatase activity and that the majority of the acylation reactions catalyzed by this enzyme take place at the sn-1 position rather than the sn-2 position (5.3:1 ratio) 21 . GPAT9 is a membrane binding protein located in the ER; that exhibits sn-1 acyltransferase activity with a preference for acyl-CoA as its substrate, shares high homology with mGPAT3 and mGPAT4, which are related to animal fat synthesis, and it plays an important role in the synthesis of plant membrane lipids and storage lipids 21,22 . GPAT1 to GPAT8 are involved in the biosynthesis of cutin or suberin in plants; and are membrane-bound proteins [23][24][25][26][27][28][29][30][31] .…”

“…In motif I, His, Asp, Gly, and Pro are located at the catalytic center of the enzymes, and Phe, Arg and Glu in motif II and motif III are the binding sites of G3P 11,21 . In addition, GPAT1 to GPAT9 contain transmembrane domains (TMDs), that help GPATs anchor to the plasma membrane [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] .…”

Considerations of AOX Functionality Revealed by Critical Motifs and Unique Domains

“…It would be worth knowing how these and other changes are definitive of a divergence between the parasitic lineage and other vascular and nonvascular plant forms. If some, or all of these changes are conserved in all plant forms, it is still plausible that AOX isoforms may function differently in the grasses when posttranslational modifications are considered [ 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Moreover, it has been theorized that mutations deleterious to an organism may be benign in others, and this may be the case with the monocots [ 25 , 37 ].…”