Integrated metatranscriptomic and metagenomic analyses of Caatinga soil and genes prospection involved on the liginin degradation.

Abstract

The Caatinga is an exclusively Brazilian biome, this mean that its biological patrimony can not be found anywhere else on the planet. Nevertheless, there is few studies done on Caatinga biological information Caatinga, being limited on flora and fauna studies. The biome is considered a region with extreme weather conditions such as high temperatures and solar radiation, high acidity and water deficit and also expected to hold microorganisms adapted to these conditions (extremophiles) that can be explored for the identification of unique and versatile enzyme arsenals (extremozymes) with wide industrial application. The microbial diversity on native Caatinga soil and its biotechnological potential are still poorly explored and existing studies just involve the analysis of cultivable microbiota. As approximately 99% of microorganisms in the soil can not be isolated by conventional methods of cultivation technologies, using molecular analysis of environment genetic material, such as "metagenomics", are needed to provide more precise information on the diversity and potential Bt microbial community. Lignin, the second most abundant biopolymer in the biosphere, is the largest source of aromatic compounds present in the soil. Soil microorganisms are able to decompose lignin using a set of ligninolytics enzymes that can also be used in other processes such as detoxification of industrial wastewater in the paper industry and biofuels, among others. Therefore, it is possible to explore new degradation pathway of these compound in soil microbes involved in the nutrient cycling. This project proposes the first time an integrated metatranscriptomic and metagenomic analyses of Caatinga soil for analyzing the structure of microbial communities and the expression of genes in soil samples in the rainy and dry seasons and identify thermostable ligninolytics enzymes. Nucleic acids (DNA and RNA) of the soil samples should be extracted and cloning for metagenomic library construction. The fosmidial DNA library and total RNA will be subjected to large-scale sequencing using the Roche 454 pyrosequencing platform for further analysis in silic. The clones library will be screened searching for genes involved in lignin degradation due biological assays based on the sequence function and similarity. This study may contribute to a understand microbial responses according to environmental changes in this biome. It is expected to find a microbial community carrying unknown genes with interesting properties involved in lignin degradation.