Draft genome sequence of multitrait plant growth-promoting Bacillus sp. strain RZ2MS9

Plant growth-promoting rhizobacteria (PGPR) are able to colonize plant rhizosphere and improve plant growth through several direct and indirect mechanisms (1), which makes them good candidates for use as biofertilizers. Members of the genus Bacillus are often reported as PGPR because of multiple traits that promote plant growth, for instance, the ability to fix nitrogen (2), produce hormones like indole acetic-acid (IAA), solubilize phosphate, and suppress pathogen growth (3). The rhizobacterium Bacillus sp. strain RZ2MS9 was isolated in Brazil from the rhizosphere of guarana, a typical tropical plant, and was identified as Bacillus thuringiensis by multi-locus sequence type (MLST) analysis. On in vitro tests, this strain was able to produce 67.40 _g IAA/ml, solubilize phosphate, produce siderophore, and fix nitrogen. The strain promoted the growth of maize (Zea mays) and soybean (Glycine max) in an experiment conducted in greenhouse conditions, suggesting that it can be used in a broad range of hosts, which is a greatly desired feature in biofertilizer development (B. D. Batista, submitted for publication). The draft genome sequence of the strain presented here will be useful to explore its genomic features as a multitrait PGPR

Draft genome sequence of Burkholderia ambifaria RZ2MS16, a plant growth-promoting rhizobacterium isolated from guarana, a tropical plant

Burkholderia ambifaria strain RZ2MS16 was isolated from the rhizosphere of Amazon guarana in Brazil. This bacterium exhibits a remarkable capacity to promote the growth of corn and soybean. Here, we report the draft genome sequence of RZ2MS16 and some genes related to multiple traits involved in plant growth promotion

Isolation and enzyme bioprospection of endopytic bacteria associated with plants of Brazilian mangrove ecosystem

The mangrove ecosystem is a coastal tropical biome located in the transition zone between land and sea that is characterized by periodic flooding, which confers unique and specific environmental conditions on this biome. In these ecosystems, the vegetation is dominated by a particular group of plant species that provide a unique environment harboring diverse groups of microorganisms, including the endophytic microorganisms that are the focus of this study. Because of their intimate association with plants, endophytic microorganisms could be explored for biotechnologically significant products, such as enzymes, proteins, antibiotics and others. Here, we isolated endophytic microorganisms from two mangrove species, Rhizophora mangle and Avicennia nitida, that are found in streams in two mangrove systems in Bertioga and Cananéia, Brazil. Bacillus was the most frequently isolated genus, comprising 42% of the species isolated from Cananéia and 28% of the species from Bertioga. However, other common endophytic genera such as Pantoea, Curtobacterium and Enterobacter were also found. After identifying the isolates, the bacterial communities were evaluated for enzyme production. Protease activity was observed in 75% of the isolates, while endoglucanase activity occurred in 62% of the isolates. Bacillus showed the highest activity rates for amylase and esterase and endoglucanase. To our knowledge, this is the first reported diversity analysis performed on endophytic bacteria obtained from the branches of mangrove trees and the first overview of the specific enzymes produced by different bacterial genera. This work contributes to our knowledge of the microorganisms and enzymes present in mangrove ecosystems

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Pathogenicity of Metarhizium anisopliae towards Rhipicephalus (Boophilus) microplus under laboratory and field conditions

Metarhizium anisopliae is one of the most studied agents of biological control of several arthropod plagues, including the cattle tick Rhipicephalus (Boophilus) microplus. Studies have been conducted to assess the fungal complex infection process towards its hosts. To accomplish that, mutant strains overexpressing or lacking assumed determinant genes for the process were constructed over the years. A fundamental experiment to demonstrate a particular gene or set of genes participation is the bioassay. The comparison of bioassays using wild and engineered strains is an essential tool to affirm a given gene is crucial in the process. Therefore, the in vitro bioassays should mimic the results obtained in tests under field conditions. In this study, tests under laboratory and filed conditions were done and a correlation analysis was performed in order to statistically validate in vitro bioassays. Tick egg laying, larvae hatching and host mortality were recorded in each experiment through 21 days, both under laboratory and field conditions. In all cases, M. anisopliae treatments were statistically different from the control treatments. A linear regression analysis was performed between the cases. Laboratory results showed a statistically significant correlation with the field conditions using the Pearson's Correlation Test (P < 0.01 host mortality - 0.969, tick egg laying - 0.977 and larvae hatching - 0.956). These results legitimize the in vitro bioassays and, therefore, constitute them as a valid tool for studying this fungus behavior, so they can be used to infer M. anisopliae response towards R. (Boophilus) microplus.CAPESCAPESCNPqCNPqFAPESPFAPESPFAPERGSFAPERGSPETROBRASPETROBRA

Describing the unexplored microorganisms associated with guarana : a typical tropical plant

In Amazon rainforest, guarana (Paullinia cupana) is a typical tropical plant with valuable pharmaceutical, economic, and social importance, especially for Brazil, which is the only commercial producer of guarana. Despite its importance and exclusive origins, knowledge regarding the microbial community associated with guarana is incipient. The microorganisms associated with this plant were only recently determined, and they were nearly unexplored until 2010 when two research groups from São Paulo and Amazonas States joined in an unprecedented project to explore the guarana microbiome. The main goal of the project was to find a biological control for Colletotrichum, the causal agent of guarana anthracnose, which is an important disease that severely affects the culture. Due to the huge diversity found in the microbial community associated with guarana, the project has extended beyond its original purpose, and other biotechnological applications have been found for these new microorganisms. From the collection of fungi and bacteria (endophytic and epiphytic, culturable and unculturable) that were obtained from different ecological niches of guarana, several studies have been conducted aimed at different applications, especially focusing on the control of plant pathogens, the promotion of plant growth, and the discovery of new compounds

Bacteriosomes in axenic plants: endophytes as stable endosymbionts

Observations of cells of axenic peach palm (Bactris gasipaes) microplants by light microscopy revealed movements of small particles within the cells. The phenomenon was characterized initially as Brownian movement, but electron microscopy revealed the presence of an intracellular bacterial community in these plants. Microscopy observations revealed the particular shapes of bacterial cells colonizing inner tissues of analyzed plants. Applying a molecular characterization by polymerase chain reaction and denaturing gradient gel electrophoresis, it was revealed the existence of bacterial rRNA within the plants. Sequencing of the rRNA identified three different phylogenetic groups; two bands had a high degree of similarity to sequences from Moraxella sp. and Brevibacillus sp., and a third sequence was similar to a non-cultivated cyanobacterium. The presence of those endosymbionts, called bacteriosomes, in axenic peach palm microplants raises the question of whether these stable endosymbionts were acquired in the process of evolution and how could they benefit the process of plants micropropagation

Cultivation of hitherto-uncultured bacteria belonging to the Verrucomicrobia subdivision 1 from the potato (Solanum tuberosum L.) rhizosphere

The role of dominant bacterial groups in the plant rhizosphere, e.g., those belonging to the phyla Acidobacteria and Verrucomicrobia, has, so far, not been elucidated, and this is mainly due to the lack of culturable representatives. This study aimed to isolate hitherto-uncultured bacteria from the potato rhizosphere by a combination of cultivation approaches. An agar medium low in carbon availability (oligotrophic agar medium) and either amended with potato root exudates or catalase or left unamended was used with the aim to improve the culturability of bacteria from the potato rhizosphere. The colony forming unit numbers based on colonies and microcolonies were compared with microscopically determined fluorescence-stained cell numbers. Taxonomical diversity of the colonies was compared with that of library clones made from rhizosphere DNA, on the basis of 16S rRNA gene comparisons. The oligotrophic media amended or not with catalase or rhizosphere extract recovered up to 33.6% of the total bacterial numbers, at least seven times more than the recovery observed on R2A. Four hitherto-uncultured Verrucomicrobia subdivision 1 representatives were recovered on agar, but representatives of this group were not found in the clone library. The use of oligotrophic medium and its modifications enabled the growth of colony numbers, exceeding those on classical agar media. Also, it led to the isolation of hitherto-uncultured bacteria from the potato rhizosphere. Further improvement in cultivation will certainly result in the recovery of other as-yet-unexplored bacteria from the rhizosphere, making these groups accessible for further investigation, e.g., with respect to their possible interactions with plants.Netherlands Genomics InitiativeDutch Ministry of Agriculture, Nature, and Food quality[KB4

Antagonistic activity of fungi from anthracnose lesions on Paullinia cupana against Colletotrichum sp.

Anthracnose is a cosmopolitan disease caused by Colletotrichum spp. that affects many crops worldwide. Observations have shown that anthracnose leaf lesions may be colonized by several non-pathogenic microorganisms. The relationship of these microorganisms with the pathogen as well as their potential as biocontrol agents is not well known. Guarana (Paullinia cupana Mart. var. sorbilis) is a typical native Amazon crop with unknown microbial diversity. Guarana productivity has been reduced by a fungal disease caused by Colletotrichum sp. In this study, we isolated 15 fungi from guarana anthracnose leaf lesions that belong to five genera: Fusarium, Phomopsis, Leptosphaeria, Microdochium and Pestalotiopsis. Four isolates from the Fusarium sp. (C6 and C10), Pestalotiopsis sp. (C3), and Microdochium sp. (P7) consistently inhibited anthracnose fungal growth in vitro. Except for the Microdochium sp. (P7), these isolates were also able to inhibit the growth of the pathogen in in vivo assays using detached guarana leaves. Some mechanisms related to the growth inhibition of this pathogen were studied. Fusarium sp. (C6) produced chitinases; Fusarium sp. (C6, C10) and Pestalotiopsis sp. (C3) produced antagonistic volatile organic compounds. These three isolates also inhibited the growth of Fusarium spp., a pathogen of several plant species, suggesting their potential broad range of growth inhibition of other phytopathogens

The auxin-producing Bacillus thuringiensis RZ2MS9 promotes the growth and modifies the root architecture of tomato (Solanum lycopersicum cv. Micro-Tom)

Strains of Bacillus thuringiensis (Bt) are commonly commercialized as bioinoculants for insect pest control, but their benefits go beyond their insecticidal property: they can act as plant growth-promoters. Auxins play a major role in the plant growth promotion. However, the mechanism of auxin production by the Bacilli group, and more specifically by Bt strains, is unclear. In previous work, the plant growth-promoting rhizobacterium (PGPR) B. thuringiensis strain RZ2MS9 increased the corn roots. This drew our attention to the strain’s auxin production trait, earlier detected in vitro. Here, we demonstrate that in its genome, RZ2MS9 harbours the complete set of genes required in two pathways that are used for Indole acetic acid (IAA) production. We also detected that the strain produces almost five times more IAA during the stationary phase. The bacterial application increased the shoot dry weight of the Micro-Tom (MT) tomato by 24%. The application also modified MT root architecture, with an increase of 26% in the average lateral root length and inhibition of the axial root. At the cellular level, RZ2MS9-treated MT plants presented elongated root cortical cells with intensified mitotic activity. Altogether, these are the best characterized auxin-associated phenotypes. Besides that, no growth alteration was detected in the auxin-insensitive diageotropic (dgt) plants either with or without the RZ2MS9 inoculation. Our results suggest that auxins play an important role in the ability of B. thuringiensis RZ2MS9 to promote MT growth and provide a better understanding of the auxin production mechanism by a Bt strain