Endogenous oscillators are ubiquitous in nature and allows organisms to synchronize their internal rhythms to the abiotic rhythms and anticipate significative changes in their habitat. Desiccation is a harsh stress that is present in all ecosystems, which through thousand years selected many groups of organisms that were able to tolerate it. Part of this tolerance is due to its anticipation through endogenous oscillators of the circadian rhythm. This project aims the study of the gene expression under desiccation of the circadian clock of two distinct organisms that are related only by a distant ancestor of the photosynthetic eukaryotes. Gracilaria tenuistipitata is a marine red seaweed which has been studied for many years in physiology, molecular biology and biological rhythms, besides its great importance in the production of carrageenan and agar. It can be found in intertidal regions of the coastline where is submitted to emersion and desiccation due the tide amplitude. Also in rhythmic way, but seasonally, the sugarcane is also submitted to desiccation which triggers the storage of energy as carbohydrates which also acts as drought protectors. For this reason it has been also exploited through hundreds of years for the production of bioethanol and sugar. Will be used strategies like quantification of the messenger RNA by RT-qPCR of the circadian rhythm genes and the genes of enzymes involved in the oxidative protection , enzymatic assays of these enzymes and analysis of the chlorophyll fluorescence response will be evaluated for the two species. For sugarcane, an analysis of an oligoarray composed by probes of 14.000 already made by other studies. This study will enhance the knowledge in the evolution and biochemical structure of the tolerance and anticipation mechanisms of desiccation.
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