Resumen. Se determinó el efecto de 44 agroquímicos (fungicidas, insecticidas y coadyuvantes) sobre el crecimiento micelial y la germinación de conidios de Trichoderma koningiopsis Th003, mediante siembra de discos de 5 mm de micelio hongo en agar Sabouraud suplementado con cada agroquímico y la siembra de conidios suspendidos en soluciones de los agroquímicos en agar agua. Para los coadyuvantes, se determinó su efecto en el establecimiento filosférico de T. koningiopsis Th003 siguiendo su población en foliolos de uchuva inoculados con el hongo suspendido en estos. Ocho fungicidas no inhibieron el crecimiento micelial del hongo o la germinación de sus conidios. Fenhexamid - Tebuconazol, Flutriafol y Kasugamicina lo inhibieron entre un 34 y 48% sin afectar la germinación, mientras que Thiram - Pirimetanil, Procloraz, Tiabendazol, Spiroxamina y Triadimenol - Tebuconazol inhibieron el crecimiento y Thiram - Pirimetanil y Dodine no permitieron la germinación de los conidios. Insecticidas y coadyuvantes presentaron una inhibición de hasta el 70% pero no afectaron la germinación de los conidios. No se observaron efectos negativos de los coadyuvantes en el establecimiento de T. koningiopsis Th003 en la filosfera, recuperando de los tratamientos aproximadamente 1x103 UFC g-1.

Abstract. The effect of 44 agrochemicals (fungicides, insecticides and adjuvants) on the mycelial growth and germination conidia of Trichoderma koningiopsis Th003 was determined by seeding of 5 mm discs of fungal mycelium in Sabouraud agar supplemented with each agrochemical and seeding of conidia suspended in solutions of agrochemicals in water agar. For the adjuvants, their effect on the phyllospheric establishment of T. koningiopsis Th003 was determined by following their population in cape gooseberry leaflets inoculated with the fungus suspended in them. Eight fungicides did not inhibit the fungus mycelial growth or the conidia germination. Fenhexamid - Tebuconazole, Flutriafol and Kasugamicina inhibited it between 34 and 48% without affecting germination, Thiram - Pyrimethanil, Prochloraz, Tiabendazol, Spiroxamina and Triadimenol - Tebuconazole inhibited the growth and Thiram - Pyrimethanil and Dodine did not allow conidia germination. Insecticides and adjuvants presented an inhibition of up to 70% but did not affect the conidia germination. No negative effects of the adjuvants on the phyllosphere establishment of T. koningiopsis Th003 were observed, recovering from the treatments approximately 1x103 CFU g-1.

Resumen. Se determinó el efecto sobre la incidencia del moho gris en postcosecha de uchuva de las aplicaciones en campo de tres bioproductos a base de Trichoderma koningiopsis, Rhodotorula mucilaginosa y Bacillus amyloliquefaciens, la alternancia del bioestimulante Kendal® y el extracto vegetal EcoSwing® y las rotaciones de fungicidas a base de Azoxistrobina - Difenoconazole y Thiram - Pyrimethanil. Semanalmente se cosechó la fruta, disponiendo en cámaras húmedas frutos con cáliz y sin este, incubadas durante siete días a 20 °C para promover el desarrollo de la enfermedad y determinar la eficacia en su control. Se realizó el seguimiento de las poblaciones de los antagonistas entre aplicaciones, mediante colecta de foliolos y el lavado en Tween 80 al 0.1%, sembrando alícuotas en medios específicos. En los frutos con cáliz la menor incidencia de la enfermedad con medias de 48 y 51% se presentó con las aplicaciones del hongo y la levadura respectivamente, mientras que en los frutos sin cáliz la incidencia no supero el 1.4% en todos los tratamientos. La población de antagonistas en la filósfera permaneció constante entre aplicaciones con recuentos de 1x103 UFC g-1 para T. koningiopsis y de 1x105 UFC g-1 para R. mucilaginosa y B. amyloliquefaciens.

Abstract. The effect of the field applications of three bioproducts (based on Trichoderma koningiopsis, Rhodotorula mucilaginosa, and Bacillus amyloliquefaciens), the alternation of the biostimulant Kendal® and the Swinglea glutinosa extract and the rotations of two fungicides (based on Azoxystrobin-Difenoconazole and Thiram-Pyrimethanol), on the incidence of gray mold in cape gooseberry postharvest was evaluated. For this purpose, the fruit was harvested weekly in the field, arranged in wet chambers with fruits with and without calyx, and incubated for seven days at 20 °C in laboratory conditions to promote the development of B. cinerea and determine the efficacy in its control. In addition, the populations of the microbial antagonists were monitored between applications by collecting the leaflets and washing them in 0.1% Tween 80 and sowing aliquots in specific culture media. In fruits with calyx, the lowest incidence of the gray mold, with averages of 48 and 51%, occurred with the applications of the bioproducts based on T. koningiopsis and R. mucilaginosa, respectively. In contrast, the incidence did not exceed 1.4% in fruits without calyx in all treatments. Furthermore, the population of microbial antagonists in the phyllosphere remained constant between applications, with counts of 1x103 CFU g-1 for T. koningiopsis and 1x105 CFU g-1 for R. mucilaginosa and B. amyloliquefaciens.

Resumen: Antecedentes y Objetivos: Los micromicetos asexuales (MA) constituyen un grupo diverso y abundante de hongos en la naturaleza. Hasta la fecha para el Estado de México no se habían realizado estudios sobre estos hongos. El objetivo de esta aportación es proporcionar información sobre la riqueza taxonómica de las especies de MA que habitan en hojas vivas senescentes y muertas de cinco especies de Quercus de un bosque templado en el municipio Huixquilucan, Estado de México, México. Métodos: Durante un año, quincenalmente se cortaron hojas de cinco especies diferentes de encinos vivas senescentes y se recolectaron hojas del suelo. Las muestras se incubaron en cámaras húmedas; la revisión microscópica se efectuó dos veces por semana. La determinación taxonómica se basó en la conidiogénesis y en las características morfométricas de los conidiomas. El material de referencia (preparaciones microscópicas), se depositó en el herbario del Instituto de Ecología, A.C. (XAL) en Xalapa, Veracruz, México. Los nuevos registros para la micobiota de México se ilustran y describen en detalle. Resultados clave: Se identificaron 30 especies de MA, 12 de ellas constituyen nuevos registros para el país y todas lo son para el Estado de México. En las hojas muertas del suelo hubo un mayor número de especies que en las hojas vivas senescentes. Ocho de los taxones identificados no habían sido recolectados desde que fueron descritos como especies nuevas para la ciencia. Trichothecium roseum, Pestalotiopsis maculans y Vermiculariopsiella immersa son micromicetos que están ampliamente distribuidos en las hojas de todas las especies de encinos estudiadas. Conclusiones: La riqueza de MA encontrada en el área de estudio evidencia que las hojas de los Quercus son sustratos que albergan una considerable riqueza fúngica aun desconocida en México. Lo anterior es una importante razón para la conservación de los bosques de Quercus y promover estudios sobre este grupo de micromicetos en nuestro país.

Abstract: Background and Aims: Asexual micromycetes (AM) are a diverse and abundant group of fungi in nature. Until now the AM had not been studied in the natural areas of Mexico State. The aim of this contribution is to provide information on the AM species richness on senescent living leaves and decomposing leaves on the ground of five species of Quercus from a temperate forest in the municipality of Huixquilucan in Mexico State, Mexico. Methods: During one year, every two weeks, samples of mature living leaves were cut from five oak species , and dead leaves were collected from the ground. Samples were incubated in moist chambers. Microscopic examination was carried out twice a week. Taxonomic determinations were based on conidiogenesis and on morphometric characters of the conidiomata. Reference material (microscopic slides) was deposited in the herbarium of the Instituto de Ecología, A.C. (XAL) in Xalapa, Veracruz, Mexico. The new records for the mycobiota from Mexico are illustrated and described in detail. Key results: Thirty AM species were determined; 12 were not known from Mexico, and all of them are new records for Mexico State. More species were found on the decaying leaves on the ground than on senescent living ones. Eight species of AM had not been collected since they were described as new species for science. Trichothecium roseum, Pestalotiopsis maculans and Vermiculariopsiella immersa are widely distributed micromycetes on the leaves of all the studied oaks. Conclusions: The richness of AM species found in the study area shows that Quercus leaves are substrates that harbor a considerable fungal richness, largely unknown in Mexico. This is an important reason for the conservation of Quercus forests and promoting studies on AM in our country.

RESUMEN Los microorganismos son esenciales para la vida en la tierra. Ellos se encuentran colonizando diferentes ambientes y en diferentes condiciones de pH, temperatura, humedad, etc. En ecosistemas naturales y agrícolas, el ciclado de nutrientes y la protección de la planta, son funciones importantes desempeñadas por los microorganismos asociados a las especies vegetales. Sin embargo, los mecanismos para colonizar esos ambientes no son completamente entendidos. En esta corta revisión se describen las comunidades bacterianas asociadas a la filosfera, con un enfoque agrícola de sus aplicaciones potenciales en esta área, relacionadas con nutrición y control biológico. En el contexto de alimentos contaminados y pérdidas en la producción agrícola, han surgido graves problemas debido al ataque de patógenos. Por otra parte, es claro que el uso de microorganismos benéficos en la agricultura es considerado como alternativa para mejorar el crecimiento, la producción y la salud de la planta. En este sentido, bacterias promotoras de crecimiento vegetal y agentes de biocontrol, aislados de la filosfera de diferentes especies vegetales han sido menos explotados que los microorganismos de la rizosfera. No obstante, el tratamiento de enfermedades, reducción de la incidencia de patógenos y la fijación de nitrógeno, en sistemas naturales y agrícolas, son ejemplos exitosos. En el contexto de seguridad alimentaria, se espera entender mejor cómo la microbiota nativa de la filosfera ayuda a la planta a protegerse contra patógenos y a la adquisición de nutrientes, para demostrar su importancia en el área agrícola. Esto indica que, fuentes microbianas pueden ser usadas para reducir el uso de productos químicos y aplicarlas como una alternativa agronómica para mejorar la productividad de los agroecosistemas.

ABSTRACT Microorganisms are essential for life on Earth. They are found in different environments and conditions, such as pH, temperature, pressure, and humidity, etc. In natural and agricultural ecosystems, nutrient cycling and plant protection are important roles played by microorganisms associated with plant species. However, the mechanisms to colonize those environments are not fully understood. This mini-review describes bacterial communities associated with the phyllosphere and an agricultural approach for potential applications. In the context of foodborne illnesses and losses in agricultural production, important issues have arisen because of pathogen attacks. On the other hand, the use of beneficial microorganisms in agriculture is an alternative for improving plant growth, health and production. In this sense, growth promoting bacteria and biocontrol agents isolated from the phyllosphere of several plant species have been less exploited than those from the soil or rhizosphere. However, the treatment of some plant diseases, reduction in pathogen incidence and nitrogen fixation in natural and agricultural systems are successful examples. In the context of food safety, a better understanding of how the indigenous phyllosphere microbiota enable plants to protect themselves against pathogens and to acquire nutrients is expected to prove its importance in the agricultural field. Microbial sources can be managed to reduce the use of chemical products and could be used as an alternative of agronomical applications for improving agroecosystem productivity.

Eight potential biological control agents (BCAs) were evaluated in planta in order to assess their effectiveness in reducing disease severity of northern leaf blight caused by Exserohilum turcicum. The assay was carried out in greenhouse. Twenty-six-day-old plants, V4 phenological stage, were inoculated with antagonists by foliar spray. Only one biocontrol agent was used per treatment. Ten days after this procedure, all treatments were inoculated with E. turcicum by foliar application. Treatments performed were: C-Et: control of E. turcicum; T1: isolate 1 (Enterococcus genus) + E. turcicum; T2: isolate 2 (Corynebacterium genus) + E. turcicum; T3: isolate 3 (Pantoea genus) + E. turcicum; T4: isolate 4 (Corynebacterium genus) + E. turcicum; T5: isolate 5 (Pantoea genus) + E. turcicum; T6: isolate 6 (Bacillus genus) + E. turcicum; T7: isolate 7 (Bacillus genus) + E. turcicum; T8: isolate 8 (Bacillus genus) + E. turcicum. Monitoring of antagonists on the phyllosphere was performed at different times. Furthermore, the percentage of infected leaves and, plant and leaf incidence were determined. Foliar application of different bacteria significantly reduced the leaf blight between 30-78% and 39-56% at 20 and 39 days respectively. It was observed that in the V10 stage of maize plants, isolate 8 (Bacillus spp.) caused the greatest effect on reducing the severity of northern leaf blight. Moreover, isolate 8 was the potential BCA that showed more stability in the phyllosphere. At 39 days, all potential biocontrol agents had a significant effect on controlling the disease caused by E. turcicum.

Se evaluó a 8 potenciales agentes de control biológico (ACB) en un ensayo in planta, con el objetivo de probar su efectividad en la reducción del daño provocado por Exserohilum turcicum, agente causal del tizón foliar del maíz. El ensayo se llevó a cabo en invernadero. Plantas de maíz de 26 días, en estadio fenológico V4, se inocularon con los potenciales antagonistas por aplicación foliar como espray. Solo un agente de biocontrol fue usado por tratamiento y todos los tratamientos se inocularon con E. turcicum 10 días después, también por aplicación foliar. Los tratamientos desarrollados fueron los siguientes: C-Et: control de E. turcicum; T1: aislamiento 1 (género Enterococcus) + E. turcicum; T2: aislamiento 2 (género Corynebacterium) + E. turcicum; T3: aislamiento 3 (género Pantoea) + E. turcicum; T4: aislamiento 4 (género Corynebacterium) + E. turcicum; T5: aislamiento 5 (género Pantoea) + E. turcicum; T6: aislamiento 6 (género Bacillus) + E. turcicum; T7: aislamiento 7 (género Bacillus) + E. turcicum; T8: aislamiento 8 (género Bacillus) + E. turcicum. La monitorización en la filosfera de los antagonistas se llevó a cabo a diferentes tiempos. Además, se determinó el porcentaje de hojas infectadas y la incidencia en plantas y hojas. La aplicación foliar de diferentes bacterias redujo significativamente la gravedad del tizón del maíz: entre el 30 y el 78% a los 20 días y entre el 39 y el 56% a los 39 días. En el estadio V10 de las plantas de maíz se observó que el aislamiento 8 (Bacillus spp.) causó el mayor efecto de reducción del tizón foliar. Además, dicho aislamiento fue el potencial agente de biocontrol que mostró mayor estabilidad en la filosfera. A los 39 días, todos los potenciales agentes de biocontrol demostraban un efecto significativo sobre el control de la enfermedad causada por E. turcicum.

Abstract Dinitrogen (N2) fixation rates were determined in the phyllosphere and in sediments with and without the presence of eelgrass (Zostera marina) in San Quintín Bay, an upwelling-influenced coastal lagoon in the NE Pacific. Samples were collected during winter 2015 at 4 sites with a gradient of oceanic influence and contrasting impact from oyster aquaculture. N2 fixation rates were determined with the acetylene reduction assay. Treatments under light and in the dark, and with and without sodium molybdate resulted in similar fixation rates, suggesting that heterotrophic nonsulfate-reducing bacteria made the largest contribution to N2 fixation, while sulfate-reducing bacteria had low fixation activity at most stations. N2-fixation rates in sediments ranged from 7 to 12 mol m-2 h-1 and were similar to those in other temperate seagrass-dominated estuaries. Winter conditions were likely responsible for small spatial differences in N2 fixation rates throughout the lagoon, even between vegetated and unvegetated sites and among depth sections of sediment cores. During winter, Z. marina growth rates and biomass are low, resulting in low and less variable release of labile organic carbon, which acts as substrate for diazotrophs. The lowest N2 fixation rates were measured at a site where high denitrification rates have been observed, probably reflecting a competition between diazotrophs and denitrifiers. The highest fixation rates were measured at the innermost station where oceanic nitrate is scarce. Epiphytic bacteria contributed ~7% of the total N2 fixation, with rates of <0.5 mol m-2 h-1. N2 fixation potentially supplied 5-10% of Z. marina N requirements and could supply ~30% of the N loss via denitrification in winter.

Resumen Se determinaron las tasas de fijación de nitrógeno molecular (N2) en la filosfera y en sedimentos con y sin presencia de pasto marino (Zostera marina) en bahía San Quintín, una laguna costera del Pacífico nororiental influenciada por surgencias. Se recolectaron muestras durante el invierno de 2015 en 4 sitios a lo largo de un gradiente de influencia oceánica y con diferente grado de impacto por la ostricultura. Las tasas de fijación de N2 se determinaron con el método de reducción de acetileno. Las tasas de fijación en los tratamientos con luz y en oscuridad, y en los tratamientos con y sin molibdato de sodio fueron similares, lo que sugiere que las bacterias heterótrofas no sulfatoreductoras fueron las principales contribuyentes a la fijación de N2, mientras que las sulfatoreductoras presentaron baja actividad de fijación en la mayoría de los sitios. Las tasas de fijación de N2 presentaron un intervalo de 7 a 12 mol m-2 h-1 y fueron similares a las reportadas para otros estuarios dominados por praderas de pastos marinos en zonas templadas. Las condiciones ambientales de invierno probablemente determinaron las pequeñas diferencias en las tasas de fijación de N2 a lo largo de la laguna, incluso entre sitios con y sin vegetación o entre las diferentes secciones de los núcleos de sedimento. Durante el invierno, las tasas de crecimiento y las biomasas de Z. marina son bajas, lo que resulta en una liberación baja y poco variable de carbono orgánico lábil, sustrato importante para los diazótrofos. Las tasas de fijación de N2 más bajas se midieron en el sitio donde aparentemente se presentan altas tasas de desnitrificación, lo que probablemente refleja una competencia entre diazótrofos y desnitrificadores. Las tasas de fijación más altas se midieron en la estación más interna, donde es escaso el aporte de nitrato oceánico. Las bacterias epífitas contribuyeron alrededor del 7% de la fijación total de N2, con tasas <0.5 mol m-2 h-1. La fijación de N2 potencialmente abasteció entre el 5% y 10% del N requerido por Z. marina y podría abastecer ~30% del N que se pierde vía la desnitrificación en invierno.

Los sistemas productivos de Rosas de corte para exportación poseen retos importantes debido a la presencia de diversos agentes fitopatógenos, siendo Botrytis cinerea uno de los más relevantes debido a su persistencia y número de hospederos alternativos. Los mercados internacionales son muy exigentes en el manejo ambientalmente sostenible de los cultivos, por lo que se ha hecho presión para la implementación de estrategias de control biológico de enfermedades. La levadura filosferica Rhodotorula mucilaginosa (Lv20) con potencial biocontrolador contra B. cinérea, fue empleada en este estudio con el objeto de generar un prototipo de formulación en base sólida con el fin de lograr una estabilidad de la actividad y viabilidad celular a través del tiempo. El empleo de mezclas de polímeros sintéticos y de origen natural permitió mantener la viabilidad de esta cepa durante 90 días a unos niveles de 1,90x10(9) células.mL-1 a una temperatura de 25°C en una formulación líquida. Así mismo, el prototipo de formulación, empleando manitol como agente nucleador en una formulación sólida de tipo granulada, logró una viabilidad celular de 1.2x10(8) células.gr-1 a los 90 días de almacenamiento a 4°C, logrando mantener una actividad biocontroladora igual a la cepa fresca sin formular o recién formulada. Estos resultados obtenidos permiten sugerir que los prototipos de formulación empleando como principio activo la levadura R. mucilaginosa, son una alternativa promisoria para el control de B. cinerea en la post cosecha de rosas variedad véndela.

Productive systems of cut roses for exportation, have important challenges due to the presence of various plant pathogens in such crops. Botrytis cinerea is one of the most important pathogen microorganism because of its persistence and number of alternative hosts plants. International markets are very demanding in terms of environmentally sustainable crop management, which has forced for the implementation of strategies for biological control of diseases. The phyllosphere yeast Rhodotorula mucilaginous (Lv20) with biocontrol potential against B. cinerea, was employed in this study in order to generate a solid prototype formulation to achieve both, the stability of its activity and cell viability over time. The use of the mix of synthetic and naturally occurring polymers allowed to maintain the viability of this strain for 90 days at 1,90x10(9) células.mL-1 at a 25 ° C in a liquid formulation. Likewise, the prototype formulation using mannitol as a nucleating agent in a granular solid formulation, allowed obtaining a cell viability of 1.2x10(8) células.gr-1 after 90 days of storage at 4 °C, maintaining a biocontrol activity equal to the fresh strain with or without formulation. These results allow us to suggest that the formulation prototypes using R. mucilaginous yeast, is a promising alternative for the control of B. cinerea in post-harvest management of roses.

The aims of this study were to select microbial isolates from phyllosphere of maize and to examine their antagonistic activity against Exserohilum turcicum. Selection was performed through the ability of isolates to compete with the pathogen using an index of dominance and to affect growth parameters of E. turcicum. Most of the epiphytic populations obtained for the screening were bacteria. These isolates were found in the order of 6 log CFU/g of leaf fresh weight. According to similar morphological characteristics and staining, 44 out of 111 isolates obtained were selected for testing antagonistic effects. At water potential, ψ, −1.38 MPa and −4.19 MPa, three Bacillus isolates showed dominance at a distance (5/0) and a significant reduction of growth rate of the pathogen. Three Bacillus isolates only decreased the growth rate of E. turcicum at −1.38 MPa. At −4.19 MPa the growth rate decreased with three isolates of Pantoea and three Bacillus. In this study a negative and significant correlation was observed between the growth rate of E. turcicum and the dominance index in the interaction of the pathogen with some bacteria. These results show that with decreasing growth rate of the pathogen the dominance index of the interaction increases. Eleven potential biocontrol agents against E. turcicum were selected.

El objetivo de este estudio fue seleccionar aislamientos microbianos de la filósfera de maíz y examinar su actividad antagonista contra Exserohilum turcicum. La selección se realizó a través de la capacidad de los aislamientos de competir con el patógeno usando un índice de dominancia y también la capacidad de afectar los parámetros de crecimiento de E. turcicum. La mayoría de las poblaciones epifíticas aisladas para la selección fueron bacterias. Estos aislamientos se encontraron en el orden de 6 log de UFC por gramo de peso fresco de hoja de maíz. En base a características morfológicas y tintóreas similares, se seleccionaron 44 de 111 aislamientos obtenidos para evaluar su capacidad antagónica. A los potenciales agua, ψ, −1,38 MPa y −4,19 MPa, tres aislados del género Bacillus mostraron dominancia a distancia (5/0) y una reducción significativa de la velocidad de crecimiento del patógeno. Tres aislamientos de Bacillus disminuyeron la velocidad de crecimiento de E. turcicum a −1,38 MPa. A −4,19 MPa la velocidad de crecimiento disminuyó con tres aislamientos de Pantoea y tres de Bacillus. En este estudio se observó una correlación negativa y significante entre la velocidad de crecimiento de E. turcicum y el índice de dominancia cuando el patógeno interactuó con algunas bacterias. Esto estaría indicando que cuando disminuye la velocidad de crecimiento del patógeno se incrementa el índice de dominancia de la interacción. Se seleccionaron once posibles agentes de biocontrol contra E. turcicum.

A plethora of microbial cells is present in every gram of soil, and microbes are found extensively in plant and animal tissues. The mechanisms governed by microorganisms in the regulation of physiological processes of their hosts have been extensively studied in the light of recent findings on microbiomes. In plants, the components of these microbiomes may form distinct communities, such as those inhabiting the plant rhizosphere, the endosphere and the phyllosphere. In each of these niches, the "microbial tissue" is established by, and responds to, specific selective pressures. Although there is no clear picture of the overall role of the plant microbiome, there is substantial evidence that these communities are involved in disease control, enhance nutrient acquisition, and affect stress tolerance. In this review, we first summarize features of microbial communities that compose the plant microbiome and further present a series of studies describing the underpinning factors that shape the phylogenetic and functional plant-associated communities. We advocate the idea that understanding the mechanisms by which plants select and interact with their microbiomes may have a direct effect on plant development and health, and further lead to the establishment of novel microbiome-driven strategies, that can cope with the development of a more sustainable agriculture.

Tropical plants including cape gooseberry (Physalis peruviana L.) are associated with different microorganisms, which carry out various processes such as improvement of availability and absorption of nutrients, decomposition of organic matter, protection against pathogens, decreased levels of chemical fertilization, among others. In this study, bacterial and fungal communities associated with rhizosphere and phyllosphere of cape gooseberry plants from Cienega (Boyacá) were identified. The samples of root, rhizosphere soil and leaves of plants were selected randomly in field. Subsequently, for the isolation of bacteria associated with rhizosphere soil, and for isolation the root and leaves of endophytes and epiphytes bacteria, and epiphytic yeast and filamentous fungi in the phyllosphere, serial dilutions were made. The abundance of endophytic bacteria was higher in the two niches, with a predominance of Gram negative bacillary with 54.36% in rhizosphere y 48.32% in phyllosphere, being the most common genus Pseudomonas. As for to mycobiota epiphytic of the phylloplane, Rhodotorula spp., was the most identified with 68.18%. Therefore, it is necessary to know the microbiota associated with cape gooseberry crops as a first step to establish alternative future biocontrol against different pathogens both soil and foliar

Microrganismos que habitam o interior e a superfície podem fornecer substancias essenciais ao crescimento das plantas, como fitormônios e nutrientes essenciais. O presente trabalho teve como objetivo isolar e caracterizar as bactérias da filosfera, do ambiente endofítico e a água de tanque associadas à Vriesea gigantea e Tillandsia aeranthos. As bactérias foram submetidas a testes de verificação de produção de sideróforos e de ácido indol acético (AIA), solubilização de fosfatos, e a presença do gene nif H. A diversidade genética dos isolados bacterianos foi analisada por rep-PCR. Sessenta e oito microrganismos foram isolados de 3 microambientes distintos de V. gigantea e de 2 microambientes de T. aeranthos. A maioria das bactérias isoladas foram bacilos formadores de esporos, gram-positivos. Todos os isolados produziram AIA in vitro na presença de quantidades pequenas de triptofano. Mais de 70% das bactérias analisadas produziram sideróforos, solubilizaram fosfatos e possuíam o gene nif H. Não foi possível distinguir grupos definidos de microrganismos baseados no microhabitat e na espécie de bromélia de onde foram isolados usando rep-PCR. A água do tanque apresentou maior diversidade microbiana quando comparada com a filosfera e o ambiente endofítico, provavelmente devido à alta concentração de nutrientes, que promove um ambiente favorável para o desenvolvimento de comunidades microbianas complexas.

Microorganisms that live inside and around a plant can supply it with essential substances, such as phytohormones and essential nutrients. The present investigation aimed to isolate and characterize the phyllosphere, the endophytic, and the water tank bacteria associated with Vriesea gigantea and Tillandsia aeranthos. The bacteria were tested for siderophore and indole-3-acetic acid (IAA) production, phosphate solubilization, and presence of the nif H gene. Genetic diversity of the bacterial isolates was evaluated by rep-PCR. Sixty-eight bacterial strains were isolated from 3 different microhabitats of V. gigantea and from 2 microhabitats of T. aeranthos bromeliad plants. Gram-positive, spore-forming bacilli comprised most bacterial isolates. All isolates produced IAA in vitro in presence of very low amounts of tryptophan. More than 70% of the evaluated bacteria presented the ability of siderophore production and phosphate solubilization, and possessed the nif H gene. It was not possible to distinguish well-defined groups of isolates based on the bromeliad species and microhabitat they inhabit using genetic characterization by rep-PCR. Water tanks presented the most abundant diversity compared with phyllosphere and endophytes, probably due to the high nutrient concentration, which promotes an ideal environment for complex microbial communities.

Mangrove forests encompass a group of trees species that inhabit the intertidal zones, where soil is characterized by the high salinity and low availability of oxygen. The phyllosphere of these trees represent the habitat provided on the aboveground parts of plants, supporting in a global scale, a large and complex microbial community. The structure of phyllosphere communities reflects immigration, survival and growth of microbial colonizers, which is influenced by numerous environmental factors in addition to leaf physical and chemical properties. Here, a combination of culture-base methods with PCR-DGGE was applied to test whether local or plant specific factors shape the bacterial community of the phyllosphere from three plant species (Avicenia shaueriana, Laguncularia racemosa and Rhizophora mangle), found in two mangroves. The number of bacteria in the phyllosphere of these plants varied between 3.62 x 10(4) in A. schaeriana and 6.26 x 10³ in R. mangle. The results obtained by PCR-DGGE and isolation approaches were congruent and demonstrated that each plant species harbor specific bacterial communities in their leaves surfaces. Moreover, the ordination of environmental factors (mangrove and plant species), by redundancy analysis (RDA), also indicated that the selection exerted by plant species is higher than mangrove location on bacterial communities at phyllosphere.

Los objetivos del presente estudio fueron aislar y determinar la presencia del patógeno Phytophthora ramorum y de otros posibles patógenos de Quercus humboldtii, y la posibilidad de utilizar la capacidad antagónica de bacterias aisladas de rizósfera y filosfera sobre estos. El estudio se realizó en la zona central del corredor de conservación Guan tiva – La Rusia – Iguaque, en los municipios de Encino (Santander), Arcabuco y Tipacoque (Boyacá). Los aislamientos de los hongos fitopatógenos, se realizaron mediante siembra directa de hojas con sintomatología fúngica, en medios selectivos sólidos OGY, Sabouraud, y PDA + acido láctico al 0.2%. Se utilizó la técnica de recuento en placa para el aislamiento de bacterias de suelo rizosférico y suelo total. No se aisló el hongo Phytophthora ramorum, pero si otros hongos fitopatógenos de los géneros Fusarium spp. y Pestalotia spp. Las poblaciones bacterianas de suelo rizosférico y suelo total fueron bajas y poco diversas, y dominadas por algunos morfotipos. Se identificaron cuatro espe cies de bacterias: Pseudomonas fluorescens, Bacillus macerans, Bacillus subtilis y Staphylococcus epidermidis. La comunidad de la filosfera estuvo dominada por Pseudomonas fluorescens. Los géneros Pseudomonas fluorescens y Bacillus subtilis, no mostraron propiedades antagónicas contra el hongo Pestalotia spp. Es indispensable realizar estudios adicionales, para confirmar si los géneros Fusarium spp. y Pestalotia spp., actúan como patógenos del Quercus humboldtii.

The objectives of this study were to isolate and determine the presence of the pathogen Phytophthora ramorum and other potential pathogens of Quercus humboldtii, and evaluate the possibility of using the antagonistic capacity of bacteria isolated from rhizosphere and phyllosphere against them. The study was conducted in the conservation corridor Guantiva – La Rusia – Iguaque, in the municipali ties of Encino (Santander), Arcabuco and Tipacoque (Boyacá). The phytopathogenic fungi were isolated using direct seeding of leaves with symptoms of fungal infection in OGY, Sabouraud, and PDA + Lactic acid at 0.2%. We used the plate counting technique for the isolation of bacteria from rhizospheric and bulk soil. Phytophthora ramorum was not isolated, but phytopathogenic fungi of the genus Fusarium spp., and Pestalotia spp., were obtained in the isolates. Microbial populations of rhizospheric and bulk soil were scarce, exhibited low diversity, and were dominated by few mor photypes. We identified four species of bacteria: Pseudomonas fluorescens, Bacillus macerans, Bacillus subtilis and Staphylococcus epidermidis. The phyllosphere community was dominated by Pseudomonas fluorescens. The species Pseudomonas fluorescens and Bacillus subtilis did not exhibited antagonistic properties against Pestalotia spp. Further studies are required to confirm Fusarium spp., and Pestalotia spp., pathogenic activity against Quercus humboldtii.

Os objetivos do presente estudo foram isolar e determinar a presençaa do patógeno Phytophthora ramorum e de outros possíveis patógenos de Quercus humboldtii, e a possibilidade de utilizar a capacidade antagônica de bactérias isoladas de rizósferas e filosfera sobre estes. O estudo se realizou em uma zona central do corredor de conservação Guantiva – A Rusia – Iguaque, nos municipios de Encino(Santander), Arcabuco e Tipacoque(Boyacá).Os isolamentos dos fungos fitopatógenos, se realizaram mediante plantação direta de folhas com sintomatologia fúngica, em meios seletivos sólidos ogy, Sabouraud e PDA + ácido lácticp a 0.2%. Utilizou-se a técnica de reconto na placa para o isolamento de bactérias do solo rizosférico e solo total. Não se isolou o fungo Phytophthora ramorum, mas sim outros fungos fitopatógenos dos gêneros Fusarium spp e Pestalotia spp. As populações bacterianas do solo rizosférico e solo total foram baixas e pouco diversas e dominadas por alguns morfotipos. Identificaram-se quatro espécies de bactérias: Pseudomonas fluorescens, Baci-llus macerans, Bacillus subtilis e Staphylococcus epidermidis. A comunidade da filosfera esteve dominada por Pseudomonas fluorescens. Os gêneros Pseudomonas fluorescens y Bacillus subtilis, não mostraram propriedades antagônicas contra o fungo Pestalotia spp. É indispensável realizar estudos adicionais para confirmar se os gêneros Fusarium spp. E Pestalotia spp. Atuam como patógenos de Quercus humboldtii.

The phyllosphere, i.e., the aerial parts of the plant, provides one of the most important niches for microbial colonization. This niche supports the survival and, often, proliferation of microbes such as fungi and bacteria with diverse lifestyles including epiphytes, saprophytes, and pathogens. Although most microbes may complete the life cycle on the leaf surface, pathogens must enter the leaf and multiply aggressively in the leaf interior. Natural surface openings, such as stomata, are important entry sites for bacteria. Stomata are known for their vital role in water transpiration and gas exchange between the plant and the environment that is essential for plant growth. Recent studies have shown that stomata can also play an active role in limiting bacterial invasion of both human and plant pathogenic bacteria as part of the plant innate immune system. As counter-defense, plant pathogens such as Pseudomonas syringae pv tomato (Pst) DC3000 use the virulence factor coronatine to suppress stomate-based defense. A novel and crucial early battleground in host-pathogen interaction in the phyllosphere has been discovered with broad implications in the study of bacterial pathogenesis, host immunity, and molecular ecology of bacterial diseases.

La filósfera es un ecosistema complejo que a pesar de contar con un gran número de microorganismos asociados, presenta pocos estudios diseñados para entender las características ecofisiológicas de los microorganismos que lo habitan. Las levaduras, como elemento importante de este hábitat, están expuestas a un ambiente variable afectado por la planta hospedera, edad y posición de la hoja, disponibilidad y calidad de nutrientes, temperatura, pH, radiación y actividad del agua. Estos factores producen una presión de selección para el establecimiento de poblaciones naturales o introducidas de levaduras que puedan desplazar otras poblaciones de hongos fitopatógenos. En este estudio se obtuvieron 80 aislamientos de levaduras filosféricas de dos cultivos de mora (Rubus glaucus), a las que se les determinó su nicho potencial en términos de su capacidad para crecer a diferentes condiciones de temperatura, pH, estrés osmótico y tolerancia a radiación UV. El estrés osmótico fue la condición evaluada más restrictiva para las levaduras obtenidas, ya que únicamente seis aislamientos presentaron un crecimiento superior a 0,3 unidades de DO a 405 nm, cuando fueron crecidas a 50% y 60% de glucosa. Este estudio permitió seleccionar diez aislamientos filosféricos de levaduras, destacados por su capacidad para crecer en un amplio rango de condiciones. De estos, cuatro aislamientos LvF 34, LvF 43, LvF 44 y LvF 50 se destacaron por su capacidad de antagonismo contra el hongo fitopatógeno Botritys cinérea. Su determinación taxonómica permitió reportar por primera vez las especies Candida kunwinensis y Rhodotorula colostri con potencial biocontrolador.

The phyllosphere is a complex ecosystem in which despite of having a great number of associated microorganisms, few studies have been designed to understand the ecophysiological characteristics of the microorganism’s inhabitant. Yeasts, as an important element of this habitat, are exposed to a variable environment, affected by the host plant, age and leaf position, availability and nutrient quality, temperature, pH, radiation and water activity. All these factors produce an important selection pressure for the establishment of natural or introduced populations of yeast which may displace other phytopathogenic fungi. In this study 80 isolates of phyllospheric yeast were obtained from two blackberry crops (Rubus glaucus). Its potential niche was determined in terms of its capacity to growth at different conditions of temperature, pH, osmotic stress and UV radiation. The osmotic stress was the most restrictive evaluated condition for the obtained yeast. Only six isolates presented a growth higher to 0.3 OD units at 405 nm, when grown at 50% or 60% of glucose. This study identified the ecological niche of ten yeast phyllospheric isolates, selected for their capacity to growth at a wide range of conditions. Four of these isolates LvF 34, LvF 43, LvF 44 and LvF 50 were selected for their antagonistic capacity against the phytopathogenic fungi Botritys cinérea. Its taxonomic determination allowed us to report for the first time isolates of Candida kunwinensis and Rhodotorula colostri with biocontrol capacity.