Séminaire de Luen Luen Li (post doc LOG/ULCO en 2016) intitulé :
METATRANSCRIPTOME ANALYSES TO GAIN A COMPREHENSIVE INSIGHT INTO TAXONOMIC AND FUNCTIONAL DYNAMICS DURING CHYTRID EPIDEMICS IN AN AQUATIC ECOSYSTEM
Date : vendredi 27 janvier 2017 de 14h00 à 15h30
Lieu : salle de conférences de la MREN LOG à Wimereux
Fungal parasitism is common in plankton communities and plays a crucial role in ecosystem by balancing nutrient cycling in the food web. Previous studies of aquatic ecosystems revealed that zoosporic chytrid epidemics represent an important driving factor in phytoplankton seasonal successions. In this study, we investigate the host-parasite interactions in Lake Pavin (France) during the spring diatom bloom and following chytrid epidemics using next generation sequencing. High-throughput sequencing of 18S rRNA hyper-variable gene region were used to determine eukaryotes microbial biodiversity, community structure, and to identify the peak of chytrids infection in Asterionella formosa. Subsequently, metatranscriptomic approach was used to identify the active part of the microbial community during the host-parasite interactions and investigate the functional/metabolic dynamics in association with the progress of chytrid infection. Differential gene expression analyses of RNAseq data allow us to specifically identify 32,651 up-regulated genes and 18,168 down-regulated genes during the chytrid epidemics. Among up-regulated chytrid genes, more than half of them have functions that are related to parasitism chronology. Through our study we have revealed possible host-parasite interaction and ecological succession. These results will be incorporated into quantitative and predictive models of energy and matter fluxes in pelagic microbial food webs.