Occurrence of myo-inositol and alkyl-substituted polysaccharide in the prey-trapping mucilage of Drosera capensis

Abstract

The chemical composition of the exudate mucilage droplets of the carnivorous plant Drosera capensis was investigated using nuclear magnetic resonance spectroscopy. The mucilage was found to contain beside a very large molecular weight polysaccharide a significant amount of myo-inositol. It appears that myo-inositol escaped detection due to the commonly applied methodology on the chemical analysis of plant mucilage, such as dialysis, precipitation of polysaccharide component with alcohol, acid hydrolysis and detection of the resultant monosaccharide (aldose) units. The possible functions of myo-inositol in the mucilage droplets and the fate after being washed off from the leaf tentacles are proposed. On the polysaccharide component, the presence of methyl ester and alkyl chain-like moieties could be confirmed. These lipophilic moieties may provide the prey-trapping mucilage with the unique adhesive property onto the hydrophobic insect body parts, as well as onto the nature’s well-known superhydrophobic surfaces such as the leaves of the sacred lotus plants. A re-evaluation of the mineral components of the mucilage, reported 40 years ago, is presented from the viewpoints of the current result and plants’ natural habitat. A case for re-examination of the well-studied plant mucilaginous materials is made in light of the new findings.Electronic supplementary materialThe online version of this article (10.1007/s00114-017-1502-4) contains supplementary material, which is available to authorized users.

Sticky mucilages and exudates of plants: putative microenvironmental design elements with biotechnological value

“…So far, only the mucilage of Drosera has been subjected to an analysis of its polysaccharide composition and was shown to contain predominantly highmolecular-weight substances that resemble pectins (Tables 1, 2) (Huang et al, 2015). Myo-inositol (MI) was identified in the lower molecular weight fraction as the predominant nonpolysaccharide organic component (Kokubun, 2017). A hypothetical polygonal polysaccharide-based nanonetwork was proposed based on atomic force microscopy images.…”

“…The architecture of the mucilage appears to have a higher order nanostructure that changes depending on the presence or absence of tensile forces (Huang et al, 2015). MI seems to be unique for sundew and could not be detected in other plant mucilages that served as control (Kokubun, 2017). These nanostructures can be transformed into a parallelogram shape upon application of a tensile force, which would explain the high tensile strength reached by the sundew mucilage (Huang et al, 2015).…”

“…These nanostructures can be transformed into a parallelogram shape upon application of a tensile force, which would explain the high tensile strength reached by the sundew mucilage (Huang et al ., ). Myo ‐inositol (MI) was identified in the lower molecular weight fraction as the predominant nonpolysaccharide organic component (Kokubun, ). MI seems to be unique for sundew and could not be detected in other plant mucilages that served as control (Kokubun, ).…”

“…Myo ‐inositol (MI) was identified in the lower molecular weight fraction as the predominant nonpolysaccharide organic component (Kokubun, ). MI seems to be unique for sundew and could not be detected in other plant mucilages that served as control (Kokubun, ).…”

The Droserasin 1 PSI: A Membrane-Interacting Antimicrobial Peptide from the Carnivorous Plant Drosera capensis

“…In species with flypaper traps, such as the Drosera, digestion generally occurs in an exposed environment over a prolonged period of time, without the benefit of a pitcher or closed trap. These plants catch prey in the sticky polysaccharide mucilage of their leaf tentacles, which then wrap around the meal to increase contact with the digestive mucilage [2]. The digestion is thus exposed to variable physical conditions from changes in weather and has increased risk of opportunistic microbial growth from bacteria and fungi that compete for nutrients from the captured prey and potentially infect the plant tissue, causing disease [3].…”