Acacio Navarrete

ABSTRACT: In this study, we analyzed the hypothesis that the combination of Nitrospirillum amazonense strain BR11145 with biological fertilizer prepared using Microgeo® and native microbiome from location of the product application results in morphological and nutritional gains for the initial development of sugarcane plants and soil chemistry. For this purpose, pre-sprouted sugarcane seedlings were grown in a greenhouse mesocosm experiment using soil amended with nitrogen/phosphorus/potassium fertilizer. The experimental treatments consisted of: 1) biological fertilizer with the addition of N. amazonense (100 mL ha-1), 2) biological fertilizer without the addition of N. amazonense, 3) inoculation with N. amazonense at a dose of 100 mL ha-1 with 2x108 viable cell mL-1, 4) inoculation with N. amazonense at a dose of 200 mL ha-1 with 2x108 viable cell mL-1, and 5) control, without the addition of biological fertilizer and N. amazonense. The biological fertilizer was applied at dose of...

This study focused on the effects of vinasse (V), a by-product of the sugar-ethanol industry, combined with mineral nitrogen fertilizer (N) and straw retention on the fungal community diversity, composition, and structure in a sugarcane-cultivated soil. The experiment consisted of a combination of V, mineral N and sugarcane-straw blanket. Soil samples were collected at 7, 157, and 217 days after planting, corresponding to maximum carbon dioxide emissions from soil after three repeated applications of fertilizers into the soil. Across 57 soil metagenomics datasets, it was revealed that the application the V in combination with N fertilizer and straw retention decreased the diversity, evenness and richness of fungi at the community level in soil. Analysis of the soil fungal community composition based on the 20 genera most abundant revealed decrease for Blastomyces, Melampsora, and Penicillium after the third application of V in combination with N fertilizer and straw blanket. An oppo...

Nowadays, due to the expansion of agricultural borders, it is highly desirable to increase the sustained productivity of sugarcane cultivars using the knowledge of soil microbial communities. In this study, twelve shotgun metagenomic datasets based on genomic DNA from soil were analyzed using the Metagenomics Rapid Annotation using Subsystem Technology (MG-RAST) and Statistical Analysis of Metagenomic Profiles (STAMP) to assess differential responses for the total soil bacterial community composition and nitrogen-cycling microbial community functional potential in soils from sugarcane field with pre-harvest burning and adjacent forest in dry and wet seasons in Southeast Brazil. The soil bacterial community revealed higher abundance for Actinobacteria in forest soil than sugarcane soil in dry and wet seasons, and an opposite pattern for Proteobacteria and Planctomycetes in these soils in both seasons. The results obtained in this study based on the KEEG map suggest that the forest so...

Here we describe a suite of methods to identify potential taxonomic and functional soil microbial indicators of soil quality and plant health in biofuel crops in various areas and land types. This approach draws on tools to assess microbial diversity, greenhouse gas fluxes, and soil physicochemical properties in bioenergy cropping systems. Integrative statistical models are then used to identify potential microbial indicators for sustainable management of bioenergy crops.

A common agricultural practice of combining organic fertilizer vinasse (a liquid residue from sugarcane ethanol production) with mineral nitrogen (N) fertilizer promotes N losses such as greenhouse gas emissions due to the effects of physicochemical changes in soil on the microbiota inhabiting this environment. In this study, we applied microarray GeoChip v.5.0M technology to obtain a better insight into the prokaryotic communities and identify and quantify the N functional gene families associated with the N processes in sugarcane soils without N fertilizer (N0), with urea at 60 kg ha−1 (N60), and with vinasse combined with urea (NV). Soil samples were collected at 7 (T7) and 150 (T150) days after N application, corresponding to maximum and minimum nitrous oxide (N2O) emissions, respectively, for molecular and physicochemical analysis. Additionally, the metagenomes of these DNA samples, previously deposited in the MG-RAST server, were accessed to investigate the functions and taxon...

We aimed to evaluate the selectivity of entomopathogenic fungi to larvae of Chrysoperla externa (Neuroptera: Chrysopidae). For this purpose, Beauveria bassiana (strain ESALQ PL63), Metarhizium anisopliae (strain ESALQ E9) and Metarhizium rileyi (strain UFMS 03) were assessed at different concentrations (1 × 107, 1 × 108 and 1 × 109 conidia mL−1). The control treatment consisted of distilled water and Tween80 0.01. The treatments were applied with a Potter spray tower using two different methodologies: direct application (DA) and dry film (DF). Up to 96 h after application, no treatment provided a larval mortality above 3%. After 120 h, only B. bassiana induced significant mortality in all instars, with rates of 26%, 17% and 10% for first, second and third instar larval periods, respectively. There was no difference regarding to the application method or concentration of conidia. The percentage of individuals that revealed changes in the length of the larval and pupal periods varied ...

Every year around 300 Gl of vinasse, a by-product of ethanol distillation in sugarcane mills, are flushed into more than 9 Mha of sugarcane cropland in Brazil. This practice links fermentation waste management to fertilization for plant biomass production, and it is known as fertirrigation. Here we evaluate public datasets of soil metagenomes mining for changes in antibiotic resistance genes (ARGs) of soils from sugarcane mesocosms repeatedly amended with vinasse. The metagenomes were annotated using the ResFam database. We found that the abundance of open read frames (ORFs) annotated as ARGs changed significantly across 43 different families (p-value < 0.05). Co-occurrence network analysis revealed distinct patterns of interactions among ARGs, suggesting that nutrient amendment to soil microbial communities can impact on the coevolutionary dynamics of indigenous ARGs within soil resistome.

A toxicidade para a minhoca Eisenia fetida de amostras de solo de landfarming de refinaria de petróleo foi avaliada em solo inoculado com comunidades de algas alóctones isoladas de solo limpo. Amostras do solo de landfarming da Refinaria de Petróleo de Paulínia (REPLAN/PETROBRAS) foram mantidas sob saturação hídrica em bandejas plásticas, em Casa de Vegetação, durante 180 dias e submetidas à inoculação algal, incorporação e remoção do crescimento algal visível. Decorridos 30 dias da inoculação, os membros das comunidades com crescimento ativo no início da colonização foram identificados ao nível gênero: Anabaena, Chroococcus, Scytonema e Lyngbya (Cyanophyta), Klebsormidium, Mougeotia e Oedogonium (Chlorophyta) e Navicula (Bacillariophyta). A toxicidade para E. fetida foi avaliada em amostras do solo de landfarming selecionadas ao acaso. Não sendo observado o efeito agudo, o efeito na biomassa de espécimes adultos da minhoca foi avaliado, indicando destoxicação do solo de landfarming...

Here we show that verrucomicrobial community structure and abundance are extremely sensitive to changes in chemical factors linked to soil fertility. Terminal restriction fragment length polymorphism fingerprint and real-time quantitative PCR assay were used to analyze changes in verrucomicrobial communities associated with contrasting soil nutrient conditions in tropical regions. In case study Model I ("Slash-and-burn deforestation") the verrucomicrobial community structures revealed disparate patterns in nutrient-enriched soils after slash-and-burn deforestation and natural nutrient-poor soils under an adjacent primary forest in the Amazonia (R = 0.819, P = 0.002). The relative proportion of Verrucomicrobia declined in response to increased soil fertility after slash-and-burn deforestation, accounting on average, for 4 and 2 % of the total bacterial signal, in natural nutrient-poor forest soils and nutrient-enriched deforested soils, respectively. In case study Model II ...

Slash-and-burn clearing of forest typically results in increase in soil nutrient availability. However, the impact of these nutrients on the soil microbiome is not known. Using next generation sequencing of 16S rRNA gene and shotgun metagenomic DNA, we compared the structure and the potential functions of bacterial community in forest soils to deforested soils in the Amazon region and related the differences to soil chemical factors. Deforestation decreased soil organic matter content and factors linked to soil acidity, and raised soil pH, base saturation, and exchangeable bases. Concomitant to expected changes in soil chemical factors, we observed an increase in the alpha diversity of the bacterial microbiota and relative abundances of putative copiotrophic bacteria such as Actinomycetales and a decrease in the relative abundances of bacterial taxa such as Chlamydiae, Planctomycetes and Verrucomicrobia in the deforested soils. We did not observe an increase in genes related to microbial nutrient metabolism in deforested soils. However, we did observe changes in community functions such as increases in DNA repair, protein processing, modification, degradation and folding functions, and these functions might reflect adaptation to changes in soil characteristics due forest clear-cutting and burning. In addition, there were changes in the composition of the bacterial groups associated with metabolism-related functions. Co-occurrence microbial network analysis identified distinct phylogenetic patterns for forest and deforested soils and suggested relationships between Planctomycetes and aluminium content, and Actinobacteria and nitrogen sources in Amazon soils. The results support taxonomic and functional adaptations in the soil bacterial community following deforestation. We hypothesize that these microbial adaptations may serve as a buffer to drastic changes in soil fertility after slash-and-burning deforestation in the Amazon region. This article is protected by copyright. All rights reserved.

ABSTRACT Land-use change is one of the greatest threats to biodiversity worldwide, and one of the most devastating changes in the use of land, especially in the tropics, is the conversion of forest to crop lands. Southeast Amazon region is considered the largest agricultural frontier in the world, where native forests are converted into soybean crop fields, a fact that highlights the social and economic importance of this system to Brazil. This study firstly, focused on the impact of land-use changes and agriculture management of Amazon forest soils on the size and composition of the acidobacterial community. Taxon-specific quantitative real-time PCR (qPCR) and pyrosequencing of 16S rRNA gene were applied to study the acidobacterial community in bulk soil samples from croplands, adjacent native forests and rhizosphere of soybean. Based on qPCR measurements, Acidobacteria accounted for 23%, 18% and 14% of the total bacterial signal in forest soils, cropland soils and soybean rhizosphere samples, respectively. From the sequences of Bacteria domain, the phylum Acidobacteria represented 28%, 16% and 17% of the sequences from forest soils, cropland soils and soybean rhizosphere samples, respectively. Acidobacteria subgroups 2-8, 10, 11, 13, 17, 18, 22 and 25 were detected with subgroup 1 as dominant among them. Subgroups 4, 6 and 7 were significantly higher in cropland soils than in forest soils, which subgroups respond to decrease of soil Aluminium. Subgroups 6 and 7 respond to high content of soil Ca, Mg, Zn, P, Fe, Mn and B. The results showed differential response of the Acidobacteria subgroups to abiotic soil factors, and indicated acidobacterial subgroups as potential early-warning bio-indicators of agricultural soil management effects in the Amazon area. Secondly, using 454 pyrosequencing, we investigated the metabolic diversity of microbial communities colonizing the rhizosphere and the bulk soil associated to soybean. The rhizosphere presented an overrepresentation of functional cores related to metabolism of nitrogen, iron, phosphorus and potassium, with bacterial groups linked to these cores found only in rhizosphere samples. Still, the network involving bacterial groups and metabolisms was less complex in rhizosphere, suggesting the specialization of some specific metabolic pathways. Taken together, these results indicate a rhizosphere effect over the soil functional community with a selection of some metabolic pathways, which could be related to plant benefits as nutrition and development. A better understanding of the functional role of the rhizosphere microbial communities is important to the development of a sustainable agriculture.

ABSTRACT The effect of mulberry (Morus alba cv. Cubana) on the population of methanogens within the rumen liquor of water buffaloes was determined using the Denaturing Gradient Gel Electrophoresis (DGGE). For this, an in vitro fermentation was made and five treatments were evaluated, which corresponded to different inclusion levels of mulberry into the diet based on star grass (SG) (Cynodon nlemfuensis): (1) 100 % of SG (control); (2) SG + 15 % M. alba cv. Cubana; (3) SG + 20 % M. alba cv. Cubana; (4) SG + 25 % M. alba cv. Cubana and (5) SG + 30 % M. alba cv. Cubana. Before the analysis of samples, a standardization of the DGGE was carried out. After 12 h of fermentation, samples of the rumen liquor were taken, from which the DNA was extracted and the DGGE was performed. The gel was scanned, images were analyzed by the Bionumerics software and dendrograms of similarities were performed. As a result, the levels of inclusion of M. alba cv. Cubana did not produced marked variations in the composition of ruminant methanogens regarding the control, grouping all treatments in a cluster with 81 % of similarity. It can be concluded that M. alba cv. Cubana has no marked effect on the population of methanogens within rumen liquor of water buffaloes. The methanogenic Archaea are the microorganisms responsible for the formation of methane within the rumen (Poulsen et al. 2012). Therefore, in order to reduce the production of this gas, so harmful for environment and animal production, many strategies have been evaluated, and the direct inhibition of methanogens is one of them (Attwood and McSweeney, 2008). Previous studies, in which M. alba cv. Cubana was evaluated as an strategy for controlling ruminant methanogenesis, confirmed that this plant managed to reduce in vitro methane production (González et al. 2010), but it did not decreased the amount of methanogens (González et al. 2011). This result led to state that the reduction of methane production could not be related to the direct inhibition of these microorganisms. Considering that traditional crop techniques were used in these researches and methanogens are difficult to cultivate, there is an important need of performing studies with more modern techniques in order to determine effectively if this plant has a direct effect on the methanogenic population. The DGGE is one of the molecular methods that could be used for this purpose (Sigler et al. 2004). Therefore, the objective of this study was to determine effect of mulberry (Morus alba cv. Cubana) on the population of methanogens within the rumen liquor of water buffaloes was determined using the DGGE. A fermentation was carried out using the in vitro gas production technique described by Theodorou et al. (1994). As donors of rumen liquor, two adult male water buffaloes (Bufalipsos crossbreds) were used, with a simple cannula in rumen and mean weight of 453 kg. They were kept in individual paddocks, under the shadows and with free access to water and food. They all were offered forage of star grass (Cynodon nlemfuensis), without supplementation. Five treatments were evaluated, which corresponded to different inclusion levels of mulberry into the diet based on star grass (SG): (1) 100 % of SG (control); (2) SG + 15 % M. alba cv. Cubana; (3) SG + 20 % M. alba cv. Cubana; (4) SG + 25 % M. alba cv. Cubana and (5) SG + 30 % M. alba cv. Cubana. Mulberry plants came from a plantation of three years, located in the Estación Experimental de Pastos y Forrajes " Indio Hatuey " , Matanzas, Cuba. These plants were found in red ferrallitic soils and fertilized with poultry manure. Leaves with young stems and petioles were manually cut, simulating animal selection. Star grass was also manually cut, at a height of 10 cm from the soil, in grazing areas from the Instituto de Ciencia Animal, located in Mayabeque, Cuba. All plant material was dried in an oven, at 60 °C for 48 h. Later, it was grounded up to the size of a 1mm particle. Chemical composition of a sample from experimental diets (table 1) was determined according to techniques described by AOAC (1995). Fibrous fractions were analyzed by the procedure of Goering and van Soest (1970). The rumen liquor of fasting animals was extracted using the cannula, with help of a thermos. This liquor was put into a hermetic vacuum flask for guaranteeing temperature conditions (39 °C) and anaerobiosis during