71 research outputs found

    Bio-prospecting for antibiotic producing bacteria from the rhizospheric culturome

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    The inappropriate use of antibiotics has increased the number illnesses and deaths because of multidrug resistant microbial caused infections. The objective of this study was to isolate rhizospheric bacteria and evaluate their potential to produce antimicrobial compounds. 418 bacterial colonies were isolated and assayed against bacteria and fungi in order to analyze their antimicrobial potential, finding 114 antimicrobial producing strains. Two of these strains with best antimicrobial spectrum of action were selected for further analyses, and were identified as Bacillus albus and Streptomycs cirratus. Their genomes were sequenced and secondary metabolism pathways were analyzed, finding genetic machinery potentially implicated in the production of new bioactive compounds.El consumo indebido de antibióticos ha incrementado el número de personas que enferman y mueren por infecciones provocadas por microorganismos resistentes a estos antimicrobianos. El objetivo de este estudio fue aislar bacterias rizosféricas y evaluar su potencial para producir nuevos compuestos antimicrobianos. Se aislaron 418 colonias y se enfrentaron a bacterias y hongos para analizar su potencial antimicrobiano, encontrando 114 bacterias productoras de antibiótico. Se seleccionaron dos de las cepas con mejor espectro antimicrobiano de acción, que se identificaron como Bacillus albus y Streptomyces cirratus. Se secuenciaron sus genomas y se analizaron las rutas relacionadas con el metabolismo secundario bacteriano, encontrando maquinaria genética que podría estar implicada en la producción de nuevos compuestos bioactivos

    Selection of the root endophyte Pseudomonas brassicacearum CDVBN10 as plant growth promoter for Brassica napus L. crops

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    [EN]Rapeseed (Brassica napus L.) is an important crop worldwide, due to its multiple uses, such as a human food, animal feed and a bioenergetic crop. Traditionally, its cultivation is based on the use of chemical fertilizers, known to lead to several negative e ects on human health and the environment. Plant growth-promoting bacteria may be used to reduce the need for chemical fertilizers, but e cient bacteria in controlled conditions frequently fail when applied to the fields. Bacterial endophytes, protected from the rhizospheric competitors and extreme environmental conditions, could overcome those problems and successfully promote the crops under field conditions. Here, we present a screening process among rapeseed bacterial endophytes to search for an e cient bacterial strain, which could be developed as an inoculant to biofertilize rapeseed crops. Based on in vitro, in planta, and in silico tests, we selected the strain Pseudomonas brassicacearum CDVBN10 as a promising candidate; this strain produces siderophores, solubilizes P, synthesizes cellulose and promotes plant height in 5 and 15 days-post-inoculation seedlings. The inoculation of strain CDVBN10 in a field trial with no addition of fertilizers showed significant improvements in pod numbers, pod dry weight and shoot dry weight. In addition, metagenome analysis of root endophytic bacterial communities of plants from this field trial indicated no alteration of the plant root bacterial microbiome; considering that the root microbiome plays an important role in plant fitness and development, we suggest this maintenance of the plant and its bacterial microbiome homeostasis as a positive result. Thus, Pseudomonas brassicacearum CDVBN10 seems to be a good biofertilizer to improve canola crops with no addition of chemical fertilizers; this the first study in which a plant growth-promoting (PGP) inoculant specifically designed for rapeseed crops significantly improves this crop’s yields in field conditions
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