6 research outputs found
Aislamiento de Bacillus solubilizadores de fosfatos asociados al cultivo del arroz.
聽The objective pursued with this study was to isolate Bacillus bacteria from rice (Oryza sativa L.) and determine its potential for phosphate solubilization. Isolates were obtained using the Microcosm model from Iacuba 30 and Perla cultivar, established by Bauta (2008) in La Habana, Cuba. Fifty eight isolates were obtained from the rice rhizosphere and inside of the roots and leaves with characteristics typical of Bacillus, such as Gram positive, rod cells and endospore formation. The qualitative capacity of these isolates for phosphate solubilization was assayed in solid NBRIP medium; the results revealed that only 19 strains solubilized inorganic phosphate and some of them changed the medium color from blue to yellow, presumably due to acid excretion. Positives were selected for assay in liquid medium, and they showed different responses in terms of time and maximum phosphate solubilization.聽聽聽El objetivo de este trabajo fue determinar la capacidad de bacterias del g茅nero Bacillus provenientes del cultivo del arroz (Oryza sativa L.) en solubilizar fosfatos. Los aislamientos se obtuvieron utilizando el modelo Microcosmos de los cultivares Iacuba 30 y Perla, en el a帽o 2008 en Bauta, La Habana, Cuba. Hubo 58 aislados, tanto rizosf茅ricos como end贸fitos de la ra铆z y de la parte a茅rea, que presentaban caracter铆sticas distintivas del g茅nero Bacillus, como respuesta positiva a la tinci贸n de Gram, forma bacilar y formaci贸n de endospora. Se realiz贸 la detecci贸n cualitativa en cuanto a la capacidad de solubilizaci贸n de fosfatos. Solo 19 aislamientos mostraron solubilizaci贸n en medio s贸lido NBRIP y en algunos casos cambiaron la coloraci贸n del medio de azul a amarillo, lo que indica la producci贸n de 谩cidos. Se seleccionaron los positivos para la cuantificaci贸n en medio l铆quido. Las cepas mostraron un comportamiento diferente cuando se midi贸 el fosfato solubilizado a distintos tiempos, variando el m谩ximo de solubilizaci贸n.
Antagonistas microbianos para el manejo de la pudrici贸n negra del fruto en Theobroma cacao L. Estado actual y perspectivas de uso en Cuba
Este trabajo tuvo como objetivo valorar las perspectivas de empleo de antagonistas microbianos en el manejo integrado de la pudrici贸n negra del fruto del cacao (Theobroma cacao L.), provocada por especies del g茅nero Phytophthora. Se resumen los principales componentes de manejo de la pudrici贸n negra del fruto, tales como control qu铆mico, m茅todos culturales, resistencia gen茅tica y control biol贸gico, profundizando en el uso y perspectivas de hongos y bacterias antagonistas. Los antagonistas microbianos constituyen una alternativa a utilizar dentro del manejo integrado del cultivo, ya que pueden mitigar los efectos delet茅reos ocasionados por Phytophthora spp. Dentro de los principales mecanismos que utilizan estos antagonistas para su acci贸n se encuentran: parasitismo, competencia y producci贸n de metabolitos antif煤ngicos. Las cepas aut贸ctonas cubanas de bacterias promotoras del crecimiento vegetal presentan actividad antagonista in vitro e in vivo ante Phytophthora palmivora (Butl) Butl, lo que sugiere sus potencialidades para el manejo de la pudrici贸n negra del fruto de cacao.Palabras clave: antagonistas microbianos, pudrici贸n negra del fruto, control biol贸gico, Phytophthora spp.MICROBIAL ANTAGONISTS TO MANAGE BLACK POD ROT IN THEOBROMA CACAO L. THEIR PRESENT STATUS AND PERSPECTIVE USE IN CUBAABSTRACT: This work was aimed to demonstrate the perspective use of microbial antagonists in the integrated management of Black pod rot in T. cacao. Some of the main management strategies of Black pod rot are summarized, making emphasis on the use and perspectives of microbial antagonists for the control of Phytophthora spp. Microbial antagonists are suggested as an alternative in cacao pest management since they could mitigate the deleterious effects caused by Phytophthora spp. Microbial antagonists exert their action mainly through parasitism, competence, and production of antifungal metabolites. Native Cuban strains have antagonistic activity in vitro and in vivo against P. palmivora, which suggests their potentialities for the production of efficient bioproducts as one of the alternatives for the integrated management of cacao.Keys words: microbial antagonist, black pod rot, biological control, Phytophthora sp
Potencialidades de las bacterias diazotr贸ficas asociativas en la promoci贸n del crecimiento vegetal y el control de Pyricularia oryzae (Sacc.) en el cultivo del arroz (Oryza sativa L.)
Este trabajo tuvo como objetivos abordar las potencialidades de uso de bacterias diazotr贸ficas asociativas en la producci贸n sostenible del cultivo del arroz (Oryza sativa L.), tratando temas como la fertilizaci贸n nitrogenada y su relaci贸n con la incidencia en la piriculariosis, a帽ublo o quemaz贸n, as铆 como sus perspectivas de uso en la promoci贸n del crecimiento y control de Pyricularia oryzae Sacc. Al aplicar bacterias diazotr贸ficas asociativas se logran aportes de nitr贸geno atmosf茅rico a la planta que permiten disminuir el uso de productos qu铆micos nitrogenados y con ello limitar el crecimiento de P. oryzae. Estas bacterias, adem谩s, liberan metabolitos en la rizosfera que disminuyen la concentraci贸n de la plaga y la severidad de la enfermedad, lo que trae consigo reducciones en la aplicaci贸n de productos qu铆micos y menor incidencia de la piriculariosis en condiciones de campo. Cepas aut贸ctonas cubanas tienen la capacidad de controlar in vitro a P. oryzae, lo que sugiere que las bacterias diazotr贸ficas asociativas que estimulan el crecimiento vegetal, pudieran disminuir los efectos nocivos ocasionados por esta plaga en el cultivo del arroz.Palabras clave: Bacterias diazotr贸ficas, arroz, nitr贸geno, Pyricularia oryzae.POTENTIALITIES OF ASSOCIATED DIAZOTROPHIC BACTERIA IN PLANT GROWTH PROMOTION AND BIOCONTROL OF PYRICULARIA ORYZAE (SACC.) IN RICE (ORYZA SATIVA L.)ABSTRACT: This work was aimed at approaching the potentialities of associated diazotrophic bacteria for the sustainable production of rice (Oryza sativa L.). Relevant topics such as nitrogen fertilization, its relationships with rice blast incidence, and the perspectives of use of associated diazotrophic bacteria for plant growth promotion and biocontrol of Pyricularia oryzae in this important crop are discussed. Associated diazotrophic bacteria have been shown to contribute with fixed atmospheric nitrogen to the rice crop making possible to reduce the application of nitrogen fertilizers, limiting with it the growth of Pyricularia oryzae. In addition, the metabolites released by these bacteria in the rhizosphere make the plague concentration and the disease severity decrease leading to the reduction of chemical product applications and a lower incidence of rice blast under field conditions. Cuban autochthonous strains have the ability to control Pyricularia oryzae in vitro, which confirms the fact that associated diazotrophic bacteria stimulate plant growth and mitigate the deleterious effects caused by this disease in rice.Key words: Diazotrophic bacteria, rice, nitrogen, Pyricularia oryza
Cell-free culture medium of Burkholderia cepacia improves seed germination rate and seedling growth in maize (Zea mays) and rice (Oryza sativa)
The saprophytic bacterium Burkholderiacepacia has been shown to play an active role as plant growth promoting bacteria (PGPB). In this study, the ability of cell-free culture medium (CFCM) of B. cepacia to improve early developmental stages of plants has been assessed on two agronomically important crops, maize (Zeamays) and rice (Oryzasativa). Treating maize and rice seeds for 45 min before germination significantly improved seed germination and consequent seedling growth. The effect of CFCM was confirmed by the increased biomass of the shoot and, mainly, the root systems of treated seedlings. Chromatographic characterization of the CFCM revealed that the spent culture medium of B. cepacia is a complex mix of different classes of metabolites including, among others, salicylic acid, indole-3-acetic acid (IAA) and several unidentified phenolic compounds. Fractionation of the CFCM components revealed that the impressive development of the root system of CFCM-treated seedlings is due to the synergistic action of several groups of components rather than IAA alone. The data presented here suggest that a CFCM of B. cepacia can be used to improve crop germination. 漏 Springer Science+Business Media B.V. 2009.SCOPUS: ar.jinfo:eu-repo/semantics/publishe