Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Brésil → Efeito da disponibilidade de água na composição e função de comunidades microbianas presentes no solo do cerrado revelado por análises metagenômicas

Universidade de Brasília (2013)

Efeito da disponibilidade de água na composição e função de comunidades microbianas presentes no solo do cerrado revelado por análises metagenômicas

Castro, Alinne Pereira de

Titre : Efeito da disponibilidade de água na composição e função de comunidades microbianas presentes no solo do cerrado revelado por análises metagenômicas

Auteur : Castro, Alinne Pereira de

Université de soutenance : Universidade de Brasília

Grade : Doutorado em Biologia Molecular 2013

Résumé
The Cerrado occurs primarily in Brazil. Its vegetation varies considerably in physiognomy and there are two well-marked and seasonal climates, one wet summer and one drought winter. Although a considerable amount of information is available regarding the fauna and flora diversity present in the Cerrado, little is known about the composition, structure and biological function of microbial communities in different native physiognomies associated to this biome. Using barcode pyrosequencing of the rRNA (16S/18S rRNA) genes and shotgun metagenomics analysis with DNA directly extracted from four contrasting physiognomies (cerrado denso, campo sujo, cerrado sensu stricto and mata de galeria) in the two different time points (drought and rain) were performed. Comparative analysis of the four type vegetation soil samples revealed a distinct distribution of bacterial, archaea and fungal phyla. According to the OTU richness estimated by Chao 1, the rain season is more species rich than drought season for bacterial and fungal communities ; by contrast, the archaeal community showed is more species rich in the drought when compared with rainy season. Apparently, there was a strong influence of soil moisture on the composition of the microbial community suggesting that the gravimetric water content of soil samples can be considered as one of the predictors of variability within the microbial diversity present in soil samples from the Cerrado biome. Furthermore, analysis of metagenomic data revealed statistically significantly increased in relative abundance of genes associated with metabolism and iron acquisition, transposable elements, dormancy and sporulation during the dry season. In addition, genes related to metabolism of DNA and proteins as well as genes linked to respiration had enriched their relative abundance during the rainy season. These functional categories can generally be associated with the mechanisms of adaptation of the microbial community to water stress. Indeed, these results can help build more comprehensive conclusions about the functional capacity of microbial communities in soils of dry and rainy seasons.

Mots clés  : Cerrados Cerrados - microorganismos Microorganismos do solo

Présentation

Version intégrale (2,84 Mb)

Page publiée le 29 novembre 2015, mise à jour le 4 juillet 2017