Overcoming deterrent metabolites by gaining essential nutrients: A lichen/snail case study

Abstract

Highlights  The lichen Usnea taylorii contains mainly usnic acid and arabitol.  In situ mass spectrometry imaging reveals the spatial mapping of the metabolites.  The land snail Notodiscus hookeri consumes lichen parts containing both metabolites.  The nutritional activity of snails is governed by the chemical quality of the lichen.  Primary metabolites overcome the deterrent effect of specialised metabolites.

Mass Spectrometry Imaging of Specialized Metabolites for Predicting Lichen Fitness and Snail Foraging

“…This appears to be compatible with the fact that this compound could come initially from a Miriquida species known to be parasitized by this over-growing species [20]. Similarly, in situ imaging by mass spectrometry of primary and specialized metabolites from the lichen Usnea taylorii demonstrated that primary metabolites such as arabitol stimulates the snail in its food choices [21].…”

“…The main advantages of MSI are in situ analyses, bypassing solubility issue encountered in mass spectroscopy in solution and avoiding the sample degradation. Laser Desorption ionization-Mass Spectrometry Imaging (LDI-MSI) has previously been applied on lichen cross-sections, which allowed discussing the roles of some metabolites in chemical ecology [20,21]. As reported previously [20], the depside miriquidic acid was isolated for the first time in the strongly competitive lichen Ophioparma ventosa.…”

“…flavonoids and terpenoids at 525 nm approximately), so it appears to be a nonselective targeting [13][14][15]. More recently, Mass Spectrometry Imaging (MSI) has become a powerful tool to assess the spatial distribution of metabolites in organisms [16][17][18][19][20][21]. The main advantages of MSI are in situ analyses, bypassing solubility issue encountered in mass spectroscopy in solution and avoiding the sample degradation.…”

“…This terrestrial snail lives in subantarctic islands and feeds only on lichens [27,28]. Previous studies have shown that the feeding strategy of N. hookeri is based on searching for lichen parts with attractive primary metabolites like polyols, even when such nutrients are mixed with potentially deterrent metabolites [21,29]. Therefore, snail gustatory responses are governed by nutrient availability [21].…”

“…Previous studies have shown that the feeding strategy of N. hookeri is based on searching for lichen parts with attractive primary metabolites like polyols, even when such nutrients are mixed with potentially deterrent metabolites [21,29]. Therefore, snail gustatory responses are governed by nutrient availability [21]. After consumption of P. crocata, the fate of lichen metabolites in the snail gut has been followed [22].…”