Ion Torrent metagenetic analysis of mussel-associated plankton diversity

Ecological models such as Dynamic Energy Budget growth models (DEB) proposed for blue mussel (Mytilus edulis) need to consider the effect of feeding and growth. Feeding is a complex process that includes regulation of filtration, as well as selection of p hytoplankton. However, although studies of bivalve feeding in the field have the advantage of taking into account the environmental variability, classical methods are not well adapted to obtain a mechanistic understanding of these processes. In the TRAPH project (Tracing phytoplankton grazed by mussels using molecular methods to identify preys and improve modeling) we conduct feeding studies in the Lysefjord where samples of phytoplankton have been obtained, associated to the inhalant and exhalant siphon and from two different zones of the gastric region of the mussels. The use of molecular methods to determine the feeding preferences is becoming increasingly popular and has the possibility to determine species specific interactions. Further, next generat ion sequencing technologies allow in depth analysis of the prey particles, which yield high resolution data on feeding preferences. Coupling this data with quantitative analyses, e.g. qPCR will yield an improved image of the mussel feeding behavior and it s correlation to environmental parameters. The results will be used to parameterize the variations inherent in the DEB model, and further provide contributions to the development of parts of ecosystem modeling systems. A critical step in this project is to generate high resolution sequencing data. The TRAPH project is therefore extended by a grant to visit Skidaway Institute of Oceanography and take part of the development of their Ion Torrent sequencing platform with a capacity of low cost sequencing of 0.5 - 2 mill reads per run. This resolution will allow us to characterize feeding preferences on a large number of field samples mussels required for ecological studies.

Ecological models as the Dynamic Energy Budget growth model (DEB) proposed for blue mussel (M. edulis) need to consider the effect of the feeding and growth. Feeding is a complex process that includes a regulation in the clearance rate and retention index and also a prey-selection that is carried out by mussels. Studies of bivalve feeding in the field have the advantage of taking into account the plankton and water dynamics. As part of the TRAPH project, Tracing phytoplankton grazed by mussels using molec ular methods to identify preys and improve modeling, it has been obtained different samples from plankton associated to the inhalant and exhalant siphon and from two different zones of the gastric region of the mussels in Lysefjorden. The use of molecular methods to determine the feeding preferences is becoming more popular in different models. The next generation sequencing technologies allow the acquisition of de novo information which could be complemented afterwards by quantitative PCR, qPCR. Ion Torr ent is an exciting new technology belonging to the Next Generation Sequencing systems that is very appropriate to get the metagenetic profile associated to different regions related to mussel feeding, as it is the case of the inhalant and exhalant siphons or the gastric shield or the crystalline style. Integrating these data altogether, it could be possible to get a clearer image of the mussel feeding behavior under different conditions. These profiles can also be useful to focus qPCR analyses on some par ticular species present in our samples. Data obtained from this next generation sequencing methods and subsequent qPCR analyses should be integrated in DEB model, providing important contribution to the development of this ecosystem modeling system. Here we propose to Skidaway Institute of Oceanography to learn this new and exciting technology, and run high throughput sequencing on the TRAPH samples. This will significantly improve the resolution of the analysis.