To identify differentially expressed genes in soybean grown under different drought conditions, cDNA libraries from roots of different genotypes were constructed. Genes of contrasting genotypes of soybean were found to be differentially expressed in plants exposed to drought conditions. A total of 753 no redundant clones were identified by PCR, and these were printed on microarray glass slides. Probes of total RNA were prepared from bulked roots subjected to 25 and 50 min (Bulk 1) or 75 and 100 min (Bulk 2) of drought stress. Differential expression of 145 genes, involved in metabolic pathways responsive to biotic and abiotic stresses, was observed. These genes were classified into nine functional categories, including energy, transcription factors, metabolism, stress response, protein synthesis, cell communication, cell cycle, cell transport, and unknown function. The functionality of some of these genes was confirmed by quantitative real-time PCR (qRT-PCR).

Até o momento poucos estudos foram realizados no Brasil a respeito da diversidade de comunidades bacterianas no solo. Com o objetivo de caracterizar as populações bacterianas presentes no solo através da análise do gene 16S rRNA, foram analisados dois solos: um caracterizado pelo uso intensivo, principalmente para a produção de tomate, feijão e milho (CS); e outro sob floresta (FS), não modificado pelo homem, ambos do município de Guaíra, no estado de São Paulo, Brasil. Usando oligonucleotídeos específicos, de genes 16S rRNA do DNA metagenomico de ambos os solos foram amplificados por PCR, amplicons foram clonados e 139 clones de duas bibliotecas foram seqüenciados. O uso da técnica de 16S rRNA, gerou a identificação de diferentes populações de bactérias de solo pertencentes aos filos Acidobacteria Actinobacteria Bacteroidetes Firmicutes Proteobacteria Verrucomicrobia, Archaea, além das não classificadas. Diferenças entre as bibliotecas FS e CS foram observadas no tamanho dos filos. Um grande número de filos e, consequentemente, uma grande diversidade bacteriana foi observada no solo sob floresta. Estes dados foram confirmados pela análise de diversidade genética realizada. A caracterização de comunidades do solo apresentada neste trabalho contribuiu fornecendo dados para estudos posteriores sobre a dinâmica das populações bacterianas em solos de diferentes condições no Brasil.Until recently, few studies were carried out in Brazil about diversity of bacterial soil communities. Aiming to characterize the bacterial population in the soil through 16S rRNA analysis, two types of soil have been analyzed: one of them characterized by intensive use where tomato, beans and corn were cultivated (CS); the other analyzed soil was under forest (FS), unchanged by man; both located in Guaíra, São Paulo State, Brazil. Using specific primers, 16S rRNA genes from metagenomic DNA in both soils were amplified by PCR, amplicons were cloned and 139 clones from two libraries were partially sequenced. The use of 16S rRNA analysis allowed identification of several bacterial populations in the soil belonging to the following phyla: Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria Verrucomicrobia in addition to the others that were not classified, beyond Archaea domain. Differences between FS and CS libraries were observed in size phyla. A larger number of phyla and, consequently, a greater bacterial diversity were found in the under-forest soil. These data were confirmed by the analyses of genetic diversity that have been carried out. The characterization of bacterial communities of soil has made its contribution by providing facts for further studies on the dynamics of bacterial populations in different soil conditions in Brazil

Studies on the impact of Eucalyptus spp. on Brazilian soils have focused on soil chemical properties and isolating interesting microbial organisms. Few studies have focused on microbial diversity and ecology in Brazil due to limited coverage of traditional cultivation and isolation methods. Molecular microbial ecology methods based on PCR amplified 16S rDNA have enriched the knowledge of soils microbial biodiversity. The objective of this work was to compare and estimate the bacterial diversity of sympatric communities within soils from two areas, a native forest (NFA) and an eucalyptus arboretum (EAA). PCR primers, whose target soil metagenomic 16S rDNA were used to amplify soil DNA, were cloned using pGEM-T and sequenced to determine bacterial diversity. From the NFA soil 134 clones were analyzed, while 116 clones were analyzed from the EAA soil samples. The sequences were compared with those online at the GenBank. Phylogenetic analyses revealed differences between the soil types and high diversity in both communities. Soil from the Eucalyptus spp. arboretum was found to have a greater bacterial diversity than the soil investigated from the native forest area.

Acidic soils occupy a vast area in the world, and the aluminum (Al) in these soils can directly interact with plant cells and tissues to inhibit their growth and reduce yields. The signalgrass Urochloa decumbens cv. Basilisk (syn. Brachiaria decumbens cv. Basilisk), a widely sown tropical forage grass, is recognized for its high productivity under intensive use, vigorous growth, ease of establishment, and good forage value throughout the year, as well as its exceptional adaptation to infertile acid soils. We sequenced the transcriptome from roots of U. decumbens cv. Basilisk under two conditions, with and without Al, using Illumina paired-end sequencing technology and performed de novo assembly of those reads, which yielded 164,920 transcripts. Of these transcripts, 113,918 were assigned a putative protein function through comparisons with different gene set databases. Additionally, 13,375 simple sequence repeat (SSR) markers were identified. Digital gene expression analyses were conducted to identify 6698 differentially expressed genes between treatments, revealing a great differences in the root transcriptional landscape when exposed to aluminum. An extensive annotation of the differentially expressed genes (DEGs), made possible to identify several transcripts with putative functions correlated to aluminum exposure, most belonging to vesicle transportation, cell wall modifications and metal handling ontologies. In this work, abundant, high-quality transcripts were obtained, providing a reference platform for future biotechnological studies and breeding programs for this species and its close relatives.