Cellular Localization of Isoprenoid Biosynthetic Enzymes inMarchantia polymorpha. Uncovering a New Role of Oil Bodies

Abstract

Like seed plants, liverworts synthesize and accumulate a myriad of isoprenoid compounds. Using antibodies raised against several isoprenoid biosynthetic enzymes, we investigated their intracellular compartmentation by in situ immunolocalization from Marchantia polymorpha. The enzymes examined were deoxy-xylulose phosphate synthase, geranyl diphosphate synthase, farnesyl diphosphate synthase, geranylgeranyl diphosphate synthase, monoterpene synthase, geranylgeranyl diphosphate reductase, phytoene synthase, and phytoene desaturase. Our results show that liverwort oil bodies, which are organelles bound by a single unit membrane, possess isoprenoid biosynthetic enzymes similar to those found in plastids and the cytosol. We postulate that oil bodies play a dynamic role in cell metabolism in addition to their role as sites of essential oil accumulation and sequestration. The occurrence of such enzymes in different cellular compartments might be due to multiple targeting of gene products to various organelles.

Synthetic Botany

“…In this light, the ultimate challenge for biological engineers will not be manipulating individual genes, but exercising control over the collective behavior of metabolic pathways and cohorts of cells and refactoring a multicellular organism's body plan to generate specialized structures and organs for manufacturing and storage of compounds of interest. For example, applications of spatially controlled gene expression in Marchantia may include targeted manipulation of carbon fixation in assimilatory filaments (Goffinet and Shaw 2009) or production of biofuel components in oil cells (Suire et al 2000). Control circuits and synthetic pathways proven in this context may serve as valuable tools for some of the largest contemporary challenges in plant metabolic engineering, such as the refactoring of nitrogen fixation pathways in plants (Rogers and Oldroyd 2014) or the introduction of C4 photosynthesis into C3 crops (Leegood 2013).…”

“…Marchantia forms simple, sheet-like tissues that can be characterized in terms of its distinct surfaces (Heberlein 1929): The lower surface shows root-like cells, called rhizoids, which are responsible primarily for the uptake of water and organic nutrients as well as the anchoring of the plant body to the substrate. The body of the thallus features scattered differentiated cells called oil bodies, which have been shown to play a role in isoprenoid metabolism (Suire et al 2000). Finally, the upper surface is composed of primitive modular complexes for photosynthesis, each of which contains a permanently open pore for gas exchange.…”

Molecular Diversity of Terpene Synthases in the Liverwort Marchantia polymorpha

“…Although many of the compounds present in these extracts have not been structurally identified, their MS patterns (parent ions and fragmentation patterns) are fully consistent with mono-and sesquiterpene classes of isoprenoids. Nonetheless, a few of the compounds have been characterized previously (Suire et al, 2000) or their retention time and MS patterns could be matched with available standards. For instance, limonene, a monoterpene, was evident during the early growth stage (i.e., gemma stage), yet decreased thereafter.…”

Oxidative Remodeling of Chromoplast Carotenoids

“…Proteins in the gel were transferred onto nitrocellulose membranes, which were probed with anti-CsCCD and antiCsZCD antibodies at a concentration of 1:2500 in Tris-buffered saline plus Tween 20 and processed as described previously (Suire et al, 2000).…”