INVESTIGADORES
ROCCHETTA iara
congresos y reuniones científicas
Título:
Changes in the life history of a long-lived freshwater bivalve linked to environmental variations: Studies at molecular, physiology and population levels
Autor/es:
IARA ROCCHETTA
Reunión:
Simposio; Humboldt Colloquium; 2018
Resumen:
During last years, I have been studied the effects ofabiotic and biotic environment factors on fitness and senescence on two natural populations ofthe freshwater bivalve Diplodon chilensisfrom environments with different limnologic characteristics (river and lake),in Northern Patagonia(Argentina). Differencesin the maximum population lifespanwere observed according to the different limnic conditions (lake: 120 years;river: 53 years). Thesestudies started with the project carried out in Germany during the Humboldtfellowship. According to theresults obtained in relation with the population and metabolic parameters,river population grows faster and invests more energy in the defense system andstress response, making this population age faster. Also, a transcriptome for D. chilensis was generated based onpooled mRNA samples from each of both sites using Illumina HiSeq2000sequencing, which was, to our knowledge, a relatively new approach infreshwater bivalve physiology.  Since my return, Icontinue with the research line with a deeper analysis in the transcriptomicresponses linked to the environmental variability (different aquatic systems,like river and lake, and seasons). This study revealed 265 differentiallyexpressed sequences. We found out a higher energy invest in gene expressionregulations for bivalves from the river between seasons, while only a few geneswere regulated for the lake individuals during the year. Immune system genes andgene related to reproduction period would seem to play an important rolebetween these two populations as many of them have been identified. We are alsostudying the variations of some immune and stress related genes over age,starting studies associated with immune-senescence. According the differences observedin the immune system efficiency between both populations, we are study anassociation with the food quality and quantity available in both aquaticsystems, which are different. During the fall, an increase of organic mattercontent coming from the river vegetation provides a higher nutrient content inthe water. While for the lake, the organic matter input comes from theautochthonous forest surrounding, with different microbiota associated, and twophytoplankton peaks occur during the year because of the mix layer periodsduring spring and at the end of the summer/autumn, characteristic of oligotrophicdimictic lakes. On the other hand, we are testing different diets (withdifferent algae) by laboratory experiments to evaluate Diplodon immune systemresponse. Identified genes from the transcriptome related to stress response,antioxidant defense system and different metabolic processes will be used toeco-physiological and bioremediation studies carried out in our lab sinceseveral years ago. It was observed in several populations changes in the growthrate, abundancy and stress parameters affecting their life expectancy accordingto the quality (aloctone coming from a sewage or autochthonous from the forest)and quantity of organic matter.