Fungal parasitism: life cycle, dynamics and impact on cyanobacterial blooms - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue PLoS ONE Année : 2013

Fungal parasitism: life cycle, dynamics and impact on cyanobacterial blooms

Résumé

Many species of phytoplankton are susceptible to parasitism by fungi from the phylum Chytridiomycota (i.e. chytrids). However, few studies have reported the effects of fungal parasites on filamentous cyanobacterial blooms. To investigate the missing components of bloom ecosystems, we examined an entire field bloom of the cyanobacterium Anabaena macrospora for evidence of chytrid infection in a productive freshwater lake, using a high resolution sampling strategy. A. macrospora was infected by two species of the genus Rhizosiphon which have similar life cycles but differed in their infective regimes depending on the cellular niches offered by their host. R. crassum infected both vegetative cells and akinetes while R. akinetum infected only akinetes. A tentative reconstruction of the developmental stages suggested that the life cycle of R. crassum was completed in about 3 days. The infection affected 6% of total cells (and 4% of akinètes), spread over a maximum of 17% of the filaments of cyanobacteria, in which 60% of the cells could be parasitized. Furthermore, chytrids may reduce the length of filaments of Anabaena macrospora significantly by "mechanistic fragmentation" following infection. All these results suggest that chytrid parasitism is one of the driving factors involved in the decline of a cyanobacteria blooms, by direct mortality of parasitized cells and indirectly by the mechanistic fragmentation, which could weaken the resistance of A. macrospora to grazing.
Fichier principal
Vignette du fichier
Gerphagnon2013_Fungal.pdf (1 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-00843243 , version 1 (10-07-2013)

Identifiants

Citer

Mélanie Gerphagnon, Delphine Latour, Jonathan Colombet, Télesphore Sime-Ngando. Fungal parasitism: life cycle, dynamics and impact on cyanobacterial blooms. PLoS ONE, 2013, 8 (4), pp.e60894. ⟨10.1371/journal.pone.0060894⟩. ⟨hal-00843243⟩
149 Consultations
332 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More