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

Acyl‐lipids such as intracellular phospholipids, galactolipids, sphingolipids, and surface lipids play a crucial role in plant cells by serving as major components of cellular membranes, seed storage oils, and extracellular lipids such as cutin and suberin. Plant lipids are also widely used to make food, renewable biomaterials, and fuels. As such, enormous efforts have been made to uncover the specific roles of different genes and enzymes involved in lipid biosynthetic pathways over the last few decades. sn‐Glycerol‐3‐phosphate acyltransferases (GPAT) are a group of important enzymes catalyzing the acylation of sn‐glycerol‐3‐phosphate at the sn‐1 or sn‐2 position to produce lysophosphatidic acids. This reaction constitutes the first step of storage‐lipid assembly and is also important in polar‐ and extracellular‐lipid biosynthesis. Ten GPAT have been identified in Arabidopsis, and many homologs have also been reported in other plant species. These enzymes differentially localize to plastids, mitochondria, and the endoplasmic reticulum, where they have different biological functions, resulting in distinct metabolic fate(s) for lysophosphatidic acid. Although studies in recent years have led to new discoveries about plant GPAT, many gaps still exist in our understanding of this group of enzymes. In this article, we highlight current biochemical and molecular knowledge regarding plant GPAT, and also discuss deficiencies in our understanding of their functions in the context of plant acyl‐lipid biosynthesis.     

Differences in suberin content and composition between two varieties of potatoes (Solanum tuberosum) and effect of post-harvest storage to the composition

The waterproof defence barrier of the potato (Solanum tuberosum) tuber periderm consists of the suberized cells of phellem. The distinct polyaliphatic and polyaromatic domains of suberin have separate roles in the development of resistance to infections. The aliphatic suberin composition and changes in the amounts of peel and extractive free suberized membrane i.e. raw suberin were studied in two potato varieties, Nikola and Asterix, during post-harvest storage for one year. The amount of peel increased from 2.33 to 4.80 g/kg in yellow-skinned Nikola and from 3.50 to 5.54 g/kg in red-skinned Asterix. The raw suberin fraction accounted for 258.1 ± 16.6 mg/g in the peel of Nikola and 250.7 ± 36.3 mg/g in the peel of Asterix on average during the storage period. In addition to increase in suberin up to 6 months, the microscopic images of the peel and raw suberin indicated that the other components contributed to the peel mass increase. The CHCl₃-soluble suberin monomer fraction after methanolysis accounted for about 20% of the raw suberin in both varieties, indicating a constant ratio of suberin polyaliphatic and polyaromatic domain over the storage period. α,ω-Diacids, fatty acids and aromatic compounds were more abundant in Asterix, while ω-hydroxyacids and fatty alcohols were more abundant in Nikola (all p = 0.000). Small changes in the aliphatic monomer composition within each variety were seen during storage.     

Agriculture group symposium: Advances in the mineral nutrition of farm livestock

Quantitative determination of suberin deposition during wound healing of potatoes (Solanum tuberosum L ) has shown that at RH> 90 % a maximum amount of suberin was deposited at 25°C. A significantly greater amount of suberin was deposited at the basal region of the tuber as compared with the apical and middle regions.