PRJNA495004
Toxigenic effects of two benthic diatoms upon grazing activity of the sea urchin: morphological, metabolomic and de novo transcriptomic analysis
The benthic zone is the lowest level of a marine or freshwater system including the bottom, such as the ocean floor or the bottom of a lake, the sediment surface and some sub-surface layers. Benthic organisms play an important role inside the trophic web and some of them play a critical role in the breakdown of organic matter. Benthic diatoms constitute a part of the phytobenthos, the primary producers living on the bottom, such as algae and aquatic plants. The effects of benthic diatoms on their consumers is not well-documented, due to difficulties in their collection, quantification and massive culturing respect to the planktonic species. Our previous results demonstrated that two abundantly occurring meroplanktonic diatoms, Nanofrustulum shiloi and Cylindrotheca closterium had toxigenic effects on the reproductive success of the sea urchin Paracentrotus lividus. Here we investigate the effects of feeding on two benthic diatoms, Cocconeis scutellum and Diploneis sp., isolated from the leaves of the seagrass Posidonia oceanica, on the sea urchin Paracentrotus lividus, using multidisciplinary approaches: i) morphological analysis, adult sea urchins were fed for one month on these two benthic diatoms and embryos deriving from them were followed until the pluteus stage and morphologically characterized; ii) gonadic tissues from these fed adults were analyzed by 1H-NMR metabolomics;; iv) molecular approaches, a de novo transcriptome assembly of P. lividus embryos has been generated, together with Real-Time qPCR on fifty genes (belonging to different functional classes and previously analyzed in response to diatom-derived natural toxins) to identify differentially expressed genes.