An acidophilic fungus is integral to prey digestion in a carnivorous plant

Abstract

Carnivorous plant leaves, such as those of the spoon-leaved sundewDrosera spatulata, secrete mucilage which hosts microorganisms potentially aiding in prey digestion. We characterised the mucilage microbial communities and identified the acidophilic fungusAcrodontium crateriformeas the ecologically dominant species. The fungus grows and sporulates on sundew glands as its preferred acidic environment. We show that theA. crateriformehas a reduced genome similar to that of other symbiotic fungi. Based on the transcriptomes when encountering prey insects, we revealed a high degree of genes co-option in each species during fungus-plant coexistence and digestion. Expression patterns of the holobiont during digestion further revealed synergistic effects in several gene families including fungal aspartic and sedolisin peptidases, facilitating the digestion of sundew’s prey, as well as transporters and dose-dependent responses in plant genes involved in jasmonate signalling pathway. This study establishes that botanical carnivory is defined by multidimensional adaptations correlated with interspecies interactions.

Culturable endophytes from carnivorous plant traps in the UK: commonality of endophyte species across host species and sites.

“…Additionally, fungi inhabiting the mucilage secretions of Drosera enhance prey digestion (Sun et al, 2023), it seems possible that fungi inhabiting these plants endophytically would also be able to contribute to prey digestion via enzyme production. Other fungi are known to inhabit the water contained within carnivorous pitcher plants forming part of a food web that aids in prey digestion, this is seen in Sarracenia purpurea and Nepenthes (Grothjan and Young 2019; Leonora S. Bittleston et al, 2018).…”

“…Considering the ubiquity of fungal endophytes, it is likely that a range of carnivorous plant -fungal endophyte associations exist. For example, new research has demonstrated that Acrodontium crateriforme, a fungus living in secretions of traps of Drosera spatulata plays a key role in carnivory by aiding in prey digestion: the presence of this fungus reduces digestion time up to 25%, in part by the production of peptidases to aid in breakdown of large proteins (Sun et al, 2023). It is not known, however, whether A. crateriforme exists endophytically inside Drosera, it may only occur inside the external secretions of the plant.…”