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Microbes have been identified as fundamental for the good health of bees, acting as pathogens, protective agent against infection/inorganic toxic compounds, degradation of recalcitrant secondary plant metabolites, definition of social group membership, carbohydrate metabolism, honey and bee pollen production. However, study of microbiota associated with bees have been largely confined to the honeybees and solitary bees. Here, I characterized the microbiota of indoor surface nest of four brazilian stingless bee species (Apidae: Meliponini) with different construction behaviors and populations. Bees that use predominantly plant material to build the nest (Frieseomelitta varia and Tetragonisca angustula) have a microbiome dominated by bacteria found in the phylloplane and flowers such as Pseudomonas sp. and Sphingomonas sp. Species that use mud and feces (Trigona spinipes) possess a microbiome dominated by coliforms such as Escherichia coli and Alcaligenes faecalis. Melipona quadrifasciata, which uses both mud / feces and plant resin, showed a hybrid microbiome with microbes found in soil, feces and plant material. These findings indicate that indoor surface microbiome varies widely among bees and reflects the materials used in the construction of the nests.

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The study of microbes associated with the coffee tree has been gaining strength in recent years. In this work, we compared the leaf mycobiome of the traditional crop Coffea arabica with wild species Coffea racemosa and Coffea stenophylla using ITS sequencing for qualitative information and real-time PCR for quantitative information, seeking to relate the mycobiomes with the content of caffeine and chlorogenic acid in leaves. Dothideomycetes, Wallemiomycetes, and Tremellomycetes are the dominant classes of fungi. The core leaf mycobiome among the three Coffea species is formed by Hannaella, Cladosporium, Cryptococcus, Erythrobasidium, and Alternaria. A network analysis showed that Phoma, an important C. arabica pathogen, is negatively related to six fungal species present in C. racemosa and C. stenophylla and absent in C. arabica. Finally, C. arabica have more than 35 times the concentration of caffeine and 2.5 times the concentration of chlorogenic acid than C. stenophylla and C. racemosa. The relationship between caffeine/chlorogenic acid content, the leaf mycobiome, and genotype pathogen resistance is discussed.

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The aim of this study was to evaluate melon growth promotion by fluorescent rhizobacteria of Pseudomonas spp. under saline stress. Soil samples were collected in agricultural properties of Juazeiro/BA, Petrolina/PE and Curaça/BA in the Submedium Region of the São Francisco Valley to conduct sampling of bacterial isolates. The obtained isolates were analyzed regarding cultural characteristics and tolerance to salinity in the following NaCl concentrations: 0; 250, 500, 750, 1000, 1250 and 1500 mM. Among the isolated bacteria, 20 were identified and used to evaluate growth promotion on melons in a protected environment. This experiment was conducted in a completely randomized 21 x 4 factorial design, with 20 bacterial isolates, one control without inoculation and four salinity levels (0.2, 2.0, 4.0 and 6.0 dS m-1), and it was replicated seven times. A total of 147 bacterial isolates were obtained from soil samples with electric conductivity ranging from 0.8 to 60.4 dS m-1. Cell growth was inhibited starting at 750 mM of "in vitro" saline concentration, with tolerance observed up to 1500 mM. Pseudomonas spp. isolates were capable of promoting melon growth under non-saline conditions and of mitigating the harmful effects of excessive concentrations of soluble salts in the growth substrate.

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Background Pseudomonas spp. promotes plant growth and colonizes a wide range of environments. During the annotation of a Coffea arabica ESTs database, we detected a considerable number of contaminant Pseudomonas sequences, specially associated with leaves. The genome of a Pseudomonas isolated from coffee leaves was sequenced to investigate in silico information that could offer insights about bacterial adaptation to coffee phyllosphere. In parallel, several experiments were performed to confirm certain physiological characteristics that could be associated with phyllospheric behavior. Finally, in vivo and in vitro experiments were carried out to verify whether this isolate could serve as a biocontrol agent against coffee rust and how the isolate could act against the infection.  Results The isolate showed several genes that are associated with resistance to environmental stresses, such as genes encoding heat/cold shock proteins, antioxidant enzymes, carbon starvation proteins, proteins that control osmotic balance and biofilm formation. There was an increase of exopolysaccharides synthesis in response to osmotic stress, which may protect cells from dessication on phyllosphere. Metabolic pathways for degradation and incorporation into citrate cycle of phenolic compounds present in coffee were found, and experimentally confirmed. In addition, MN1F was found to be highly tolerant to caffeine. The experiments of biocontrol against coffee leaf rust showed that the isolate can control the progress of the disease, most likely through competition for resources. Conclusion Genomic analysis and experimental data suggest that there are adaptations of this Pseudomonas to live in association with coffee leaves and to act as a biocontrol agent.