Genômica comparativa de algas da classe trebouxiophyceae

• Autor(a) principal: Rangel, Darlene Lopes
• Data de Publicação: 2015
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNIPAMPA
• Texto Completo: http://dspace.unipampa.edu.br/jspui/handle/riu/465
• topic: Prasiola crispa; Genoma Plastidial; Trebouxiophyceae; Genoma Mitocondrial; Prasiola crispa; Plastid genome; Mitochondrial genome; Trebouxiophyceae

The Trebouxiophyceae class is a group of morphologically heterogeneous algae mainly inhabit the soil and freshwater. These algae are present also in the Antarctic continent, which is the fifth largest continent in size, with approximately 13.7 million km2. It is a continet of extremes, being the highest, coldest, driest and with the strongest winds. In addition to these extreme weather conditions, UVA and UVB radiation are aspects that affect the structure and development of plants. The most commonly reported specie is Prasiola crispa (Lightfoot) Kützing. This algae usually grows in moist soils that are fertilized by the guano bird, within and adjacent to colonies of penguins It tolerates repeated freeze/thaw cycles in the spring and fall, freezing during the winter, and high UV radiation levels during the summer. The organisms in the Antarctic vegetation, because of their peculiar characteristics, become a good target to study its accessory organelles. The exploration of the genome of accessory organelles revealed a surprising genomic architecture. Some of the most varied and unusual mitochondria and chloroplast DNA comes from green algae. Despite numerous biological functions of both organelles, they rely heavily on imported and encoded proteins from the nucleus. Understanding the genome of accessory organelles represents a strong impact in the fields of evolution, biology and biotechnology. Based on the current literature on P. crispa and how the genome of organelles provide such important information, our group sequenced the mitochondrial and plastid genomes from the Antarctic algae P. crispa. Organelle DNA was sequenced by the Macrogen DNA Sequencing Service in a Solexa-IlluminaHiSeq 2500 New Generation Sequencing (NGS) device according to the manufacturer’s instructions. Sequence assembly was performed with SOAPdenovo2 software v2.01. All ORFs were annotated using CpGAVAS and Mitofy for chloroplast and mitochondrial genomes respectively. The data obtained from the NCBI relating to species of Trebouxiophyceae algae with mtDNA and cpDNA sequenced were compared with the data of P. crispa relative to base pair size, number of CDS, G+C content, tRNA, rRNA, as well as absence and presence of genes related to energy production and oxidative stress. Based on our results, it was observed that P. crispa possesses one of the largest mitochondrial and plastid genome, but in relation to the number of genes between the Trebouxiophyceae species. P crispa has the smallest gene content, it does not contain several genes related to the photosystem I and II and the synthesis of ATP in the chloroplast and these are related to important functions of the plant for energy metabolism. Various genes related to mitochondrial oxidative complex and ATP synthesis are absent, and these are critical functions for the organism survival. One possible explanation is that these genes have been incorporated into the nuclear genome of the plant during it development. Future studies, such as the sequencing of P. crispa nuclear genome may elucidate issues like this. Keywords: Prasiola crispa, mitochondrial genome, plastid genome, Trebouxiophyceae