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Black pod rot is the most important disease affecting Theobroma cacao in Cuba. Plant growth promoting bacteria (PGPB) are considered an alternative for controlling plant disease in the context of the integrated management. The present work was aimed to evaluate Pseudomonas chlororaphis strain CP07, isolated from T. cacao rhizosphere, as potential PGPB against P. palmivora in cacao plants cultivated under controlled conditions. Three genotypes of Cuban traditional cacao of the group Trinitario and the genotype UF 677 were used. The effect of CP07 was evaluated by using detached leaf tests and in planta assays with plants obtained in vitro from both seeds and micrografting. Inoculation of P. palmivora in control plants showed that genotypes EICB-371, EICB-384 and UF 677 were highly susceptible to the disease (71.4 to 99% disease severity) while EICB-385 was significantly less susceptible (39 to 54.5%). In EICB-371 and EICB-385 genotypes, disease symptoms were significantly reduced in presence of CP07 compared to the control plants in all assays. In contrast, for EICB-384 and UF 677 genotypes, there was not reduction of disease severity in plants pre-treated with CP07. Results show the protective effect of treating cacao plants with CP07 against P. palmivora. Plant genotype significantly influenced the protective ability of bacteria affecting the CP07-mediated disease control. Results suggest that depending on cacao genotype, CP07 has a potential for inducing plant defense against P. palmivora which can be used in the control of black pod rot.

This study aimed to evaluate in vitro grafting of Theobroma cacao where seedlings of the UF 677 genotype were used as the rootstock and apices or axillary buds of a Trinitarian genotype were used as scion. Three methods of grafting using scions from seedlings were evaluated. Apical grafts using apex and side grafts using apex displayed better graft success (95 and 80%, respectively). However, side grafts using axillary buds reached a greater height on average and a higher number of leaves per plant (1.76 cm and 3.72, respectively). Histological studies revealed new vascular elements at the graft union area. Side grafts with axillary buds provided the highest survival rate (82%) after the acclimatization step. A shoot of at least 1 cm with two leaves is required for plant survival after transfer to ex vitro conditions. Side grafting was carried out with axillary buds from adult trees and nursery plants. Only the grafts with buds from nursery grafted plants were successful, with a rate of 26%. Overa...

The genus Coffea spp. is the most important of the Rubiaceae family and both Coffea arabica L. and Coffea canephora P. constitute the most economically important species. This research aimed to characterize morphologically, physiologically and biochemically diazotrophic rhizobacteria associated with coffee plants from a living collection, and to study their plant growth promoting potential. Semi-solid nitrogen-free media NFb and JNFb were used to isolate the bacteria. Ten isolates were selected for micro-morphological, physiological-biochemical and plant growth potential characterization. The solubilization of calcium phosphate, the synthesis of indole compounds and the production of siderophores were analyzed. The results showed that high population levels of bacteria, fungi and actinomycetes are present in the rhizosphere of the coffee collection. 95 native isolates were selected, and 8 were classified as Azospirillum and Herbaspirillum. Phosphate solubilizing activity was detected in the ten isolates, highlighting the C8 isolate. Synthesis of indole compounds was also detected by the ten isolates, although in amounts significantly lower than the controls. Only isolates C2, C9 and C10 produced siderophores. The multivariate cluster analysis resulted in the formation of three groups, the C8 grouped with the positive control in one of them. The beneficial potential of this isolate makes it a source of interest to develop a biostimulant product that could be applied as a sustainable alternative for the cultivation of Coffea sp.

Las enfermedades causadas por potyvirus no pueden ser controladas una vez que la planta es infectada al igual que ocurre con otras enfermedades virales. Por otro lado, la t ransmisión no persistente por áfidos representa un desafío para las estrategias de prevención y control de las enfermedades virales en cultivos de importancia económic a. Sin embargo, un conjunto de medidas de manejo integrado de las enfermedades que afecta n a los cultivos, pudieran evitar la introducción de virus a plantaciones sanas y jardines , o evitar su diseminación. No obstante y a pesar de todo el trabajo realizado, en los últimos años se ha comenzado a observar un fuerte incremento de los síntomas a sociados a estos virus en los cultivos de pimiento ( Capsicum annuum L.) , lo que supone la incidencia de nuevos potyvirus circulantes o variantes recombinantes de los virus ya presentes, comportamiento que es muy frecuente en esta familia viral. Por lo q ue este trabajo tiene como objetivo estandarizar una técnica para el diagnóstico molecular de potyvirus mediante el empleo de la RT - PCR con cebadores genéricos. Se realizó un análisis in silico de la capacidad de los cebadores CP1 y CP 2 para detectar la p resencia de potyvirus y demostrar la amplificación de una región conservada que contiene el gen que codifica para la proteína de la cápsida viral . P osteriormente , se procedió a la estandarización de l ens ayo de RT - PCR en una sola etapa; l os resultados dem ostraron que la técnica empleada es altamente sensible y específica para el diagnóstico genérico de potyvirus. Además, los resultados de este trabajo constituyen los primeros de este tipo para el país, ya que por primera vez se asiste al programa de mejora miento genético del pimiento en Cuba con un método de diagnóstico molecula

The capacity to solubilize phosphate and to produce indole compounds Indole Acetic Acid type, was evaluated in 15 strains isolated from castor bean lignocellulosic residues (Ricinus communis). To determine the solubilizing activity of phosphates a qualitative test by using Pikovskaya culture medium was employed and for the evaluation of the production of indole compounds (IAA) a Salkowsky colorimetric analysis technique was applied. Among the microorganisms tested, the Bacillus pumilus GIBI 206 demonstrated capacity to solubilize phosphates and Bacillus subtilis GIBI 200 showed of capacity to solubilize phosphates and to produce Indoleacetic Acid (IAA). To determine the effect of the Bacillus subtilis strain on germination and growth promotion, tomato seeds (Solanum lycopersicum ‘Santa Clara’) were inoculated; the inoculation of the seeds along with the microorganism revealed statistically significant differences, during the germination stage compared to the control treatment. Nevertheless, it revealed a positive influence on the development of tomato plants, originating a significant increase on the mass and length of its stem and root. The results of this research offer the possibility of using the Bacillus subtilis as a growth promoter in tomato seedlings and in the formulation of bio-products. La capacidad para solubilizar fosfatos y producir compuestos indólicos del tipo Ácido Indol Acético, se evaluó en 15 cepas aisladas de residuos lignocelulósicos de higuerilla (Ricinus communis). Para determinar la actividad solubilizadora de fosfatos se realizó una prueba cualitativa utilizando medio de cultivo Pikovskaya y para evaluar la producción de compuestos indólicos (AIA) se empleó la técnica colorimétrica de Salkowsky. Entre los microorganismos evaluados, Bacillus pumilus GIBI 206 mostró tener la capacidad para solubilizar fosfatos y Bacillus subtilis GIBI 200 evidenció capacidad para solubilizar fosfatos y producir Ácido Indolacético (AIA). Para determinar el efecto de la cepa Bacillus subtilis sobre la germinación y promoción de crecimiento, se inoculó en semillas de tomate (Solanum lycopersicum cultivar Santa Clara); la inoculación de las semillas con el microorganismono mostró diferencias estadísticamente significativas en el tiempo de germinación en comparación con el tratamiento control, sin embargo mostró influir positivamente en el desarrollo de las plantas de tomate generando un aumento significativo sobre la masa y longitud del tallo y de la raíz. Los resultados de esta investigación ofrecen la posibilidad de utilizar a Bacillus subtilis como promotora de crecimiento en plántulas de tomate y en la formulación de bioinsumos

The effect of chitosan was evaluated in three isolates of Rhizopus stolonifer from infected tomatoes that were harvested in different regions of the state of Morelos, Mexico. Changes in the membrane integrity of spores, modifications in pH media and the proteins released were analysed in each isolate against three different molecular weights of chitosan at three fixed concentrations. There was an observed decline in the integrity of spores in the presence of chitosan at all the concentrations evaluated. The protein released was different depending on the isolate, kind of chitosan and used concentration. There was a significant difference in the pH changes on the growth media for all the tested isolates. Chitosan of high molecular weight showed the best results to inhibit the infection caused by R. stolonifer on the tomato fruits. The severity of symptoms of soft rot was not related with the molecular weight of chitosan.

Introduction Theobroma cacao L. is economically speaking the most important species of the genus Theobroma . Cacao is cultured in tropical regions and its yield is affected by several diseases, such as black pod. Black pod rot in cacao . Cacao black pod, particularly, is an economically serious problem in all areas of the world where cacao is grown, causing significant pod losses of up to 30% and killing up to 10% of the trees annually. The disease is caused by different species of the stramenopile genus Phytophthora and, once it has infected a cacao field, its control is fairly difficult. Black pod rot control strategies . Several approaches are used to manage black pod: chemical control, phytosanitary and cultural methods, genetic resistance, and biological control. Losses in yield due to black pod could be reduced through integrated management practices, although the results may vary for each cacao-growing region. Main challenges and new approaches Black pod control could be achieved if an integrated management strategy is established, with the combination of biological and chemical methods, genetic control, and adequate cultural methods in an integrated program.

The aerobiology can play a key role in protecting the rice crop since many fungi can cause serious damage to agricultural areas. In this way, the ideal time to implement different security measures can be identified. To determine the presence of potentially pathogenic fungi in the air of the rice agroecosystem, a weekly monitoring of viable fungi was carried out using a volumetric sampler. Collected fungi were quantified, isolated, and identified based on their morphological characteristics. The results obtained demonstrated that the annual average concentration of filamentous fungi in the atmosphere of rice agroecosystem studied was 1,225 cfu m−3 levels ranging between 115 cfu m−3 (April) and 2,865 cfu m−3 (August). Pyricularia grisea was detected in the air for 5 months, since the second week of June until the first week of October, and highest average concentration (25 cfu m−3) was observed in August. Of the meteorological factors evaluated, temperature and relative air humidity influence the concentration of propagules of P. grisea in the air. Besides, other fungi were detected such as Curvularia, Bipolaris, Alternaria, and Cercospora, all with relevance to rice cultivation. This is the first characterization of aeromycological biodiversity in the studied region.

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.

Plants growth promoting bacteria (PGPB) are capable of increasing directly or indirectly crop yield. Burkholderia and Pseudomonas have been found in large populations, which inhabit in the rhizosphere of several agriculture crops. The aim of this study was to determine the antagonistic activity in vitro and in vivo of Cuban native plant growth promoting rhizobacteria against Fusarium verticillioides M1, and to assess their ability to produce IAA and to promote plant growth. The bacterial strains were tested to assess their fungal growth inhibition and plant growth stimulation. The plant growth assays were done in a modified microcosm experiment and in greenhouse conditions. The results demonstrated that these rhizobacteria produce IAA and exhibit antagonistic effect on F. verticillioides M1 inoculated in the substrate. Burkholderia sp. MBf21, MBp1, MBf15 and Pseudomonas fluorescens MPp4 stood out for their plant growth stimulation in maize and for the biological control exerted on F. verticillioides M1. The strains Burkholderia sp. MBf21 and MBf15 showed the best results in disease suppression, which was achieved up to 80%. These results have practical relevance, since potentially effective bacterial strains were selected and could be used in agriculture, for the enhancement of plant growth and disease control in maize crop.

Aim: To isolate and characterize rhizobacteria from Theobroma cacao with antagonistic activity against Phytophthora palmivora, the causal agent of the black pod rot, which is one of the most important diseases of T. cacao. Methods and Results: Among 127 rhizobacteria isolated from cacao rhizosphere, three isolates (CP07, CP24 and CP30) identified as Pseudomonas chlororaphis, showed in vitro antagonistic activity against P. palmivora. Direct antagonism tested in cacao detached leaves revealed that the isolated rhizobacteria were able to reduce symptom severity upon infection with P. palmivora Mab1, with Ps. chlororaphis CP07 standing out as a potential biocontrol agent. Besides, reduced symptom severity on leaves was also observed in planta where cacao root system was pretreated with the isolated rhizobacteria followed by leaf infection with P. palmivora Mab1. The production of lytic enzymes, siderophores, biosurfactants and HCN, as well as the detection of genes encoding antibiotics, the formation of biofilm, and bacterial motility were also assessed for all three rhizobacterial strains. By using a mutant impaired in viscosin production, derived from CP07, it was found that this particular biosurfactant turned out to be crucial for both motility and biofilm formation, but not for the in vitro antagonism against Phytophthora, although it may contribute to the bioprotection of T. cacao. Conclusions: In the rhizosphere of T. cacao, there are rhizobacteria, such as Ps. chlororaphis, able to protect plants against P. palmivora. Significance and Impact of the Study: This study provides a theoretical basis for the potential use of Ps. chlororaphis CP07 as a biocontrol agent for the protection of cacao plants from P. palmivora infection. © 2015 The Society for Applied Microbiology.

We studied the echolocation behaviour of Nycticeius cubanus in the field in western Cuba. During hunting, N. cubanus search for insects emitting cries that sweep from 80 to 40 kHz in 4 to 12 ms. Search call characteristics correlate with the clutter structure of the hunting areas. Bats hunting in an uncluttered space broadcast longer and narrower signals, while bats hunting in cluttered space broadcast shorter and broadband signals. Longer calls were emitted with longer intervals while the duty cycle was kept below 15 % during search and approach phases. The call's minimal frequency remained about 43 kHz showing variation coefficients of less than 3%. As a consequence, bandwidth correlates positively with the maximal frequency. Calls emitted by different sympatric individuals are accurately classified by sender using a discriminant function analysis, suggesting vocal signatures in N. cubanus. The statistical analysis of several passes of calls broadcast during the hunting activity of a single ind...

El arroz es fuente de alimento para una gran parte de la población mundial, con alto promedio de consumo anual. En este cultivo las enfermedades de origen microbiano constituyen uno de los factores que inciden en la obtención de bajos rendimientos y calidad de los granos. La piriculariosis o añublo del arroz, causada por Pyricularia grisea, es la enfermedad más importante en este cultivo en América Latina, ya que puede provocar hasta el 100% de reducción de los rendimientos. Como parte de la estrategia de agricultura sostenible, se trata de controlar estos patógenos y lograr altos rendimientos del cultivo mediante una combinación adecuada de fertilizantes químicos y productos biológicos. En este sentido, la aplicación de inoculantes bacterianos constituidos por bacterias promotoras del crecimiento vegetal (Plant Growth- Promoting Bacteria, PGPB, por sus siglas en inglés) ha constituido una alternativa ecológica que favorece la conservación del medioambiente y el ecosistema. Este trabajo tiene como objetivo abordar el estado actual y las perspectivas de uso de bacterias rizosféricas en el control de Pyricularia grisea en el cultivo del arroz, tratando algunos temas relevantes, como son las principales enfermedades que afectan al cultivo, los géneros de PGPB más utilizados para el control de las mismas y sus principales mecanismos de acción. Rice is an important food supply for a large part of the world population and its consumption rates are very high. Microbial diseases are one of the main causes that provoke low yields and low-quality spotted grains. Although fungi, bacteria and viruses are mostly the responsible for these losses, fungal diseases strike more frequently. Among fungi, Pyricularia grisea, the blast fungus is responsible for up to 100% of reduction in yields, being the blast the most important rice disease in Latin America. To control this pathogen, a strategy of sustainable agriculture might be developed, combining accurately chemical and biological products. PGPB based bioproducts have been considered as an eco-friendly alternative, which favours environment preservation. This work was aimed to approach the current status and outlook of the use of rhizobacteria in the biocontrol of Pyricularia grisea on rice. Main diseases attacking rice, most beneficial PGPB and its mechanisms of action will be discussed too in this review.

La fumagina (Capnodium spp.) afecta a las plántulas de café durante la aclimatación. El objetivo de este estudio fue evaluar el efecto de un producto biológico obtenido de Burkholderia cepacia en el control de esta enfermedad. Se emplearon diferentes concentraciones del producto (50-250 mg L-1) para evaluar su efecto en la inhibición del crecimiento micelial de Capnodium spp. Se estudió el efecto del producto biológico sobre el índice de infección, crecimiento (pares de hojas, altura y peso seco), contenido de proteínas totales, fenoles y sobrevivencia de las plántulas. Los resultados mostraron una inhibición del crecimiento de Capnodium spp. hasta en un 79.3% (200 mg mL-1). Se logró el control total de la enfermedad (150 mg mL-1) en el clon M-28, del 95 y 90% en los clones M-229 y K-234 (150-200 mg mL-1). Además se observó un mejor comportamiento en los indicadores del crecimiento, proteínas, fenoles y sobrevivencia de las plántulas. Los resultados corroboraron la factibilidad del uso de este producto biológico para el control de la fumagina en plántulas de café durante la aclimatación.

"Se evaluaron diferentes rizobacterias en la elicitación de resistencia sistémica inducida (RSI) en los sistemas frijol (Phaseolus vulgaris) - Colletotrichum lindemuthianum y tomate (Lycopersicon esculentum) - Botrytis cinerea. Como inductores se utilizaron las cepas de Pseudomonas aeruginosa 7NSK2-562, KMPCH y 7NSK2, Pseudomonas fluorescens WCS 417 y J-143, Burkholderia cepacia 0057, y el producto químico Benzothiadiazole (BTH). Para la elaboración de los inóculos fúngicos se utilizaron las cepas de Colletotricum lindemuthianum 06/038 y Botrytis cinerea R16. Los resultados demostraron que en el cultivo del frijol, las cepas de P. aeruginosa 7NSK2 y KMPCH, P. fluorescens WCS 417 y J-143, y B. cepacia 0057, así como el BTH indujeron resistencia en las plantas contra C. lindemuthianum. P. aeruginosa KMPCH y P. fluorescens J-143 fueron las mejores cepas en este sistema. En el cultivo del tomate todas las rizobacterias estudiadas y el BTH inducen resistencia contra B. cinerea. Las cepas de B. cepacia 0057, P. fluorescens J-143 y P. aeruginosa KMPCH manifestaron las mejores respuestas, demostrándose un grado de inducción de resistencia dependendiente de la especie vegetal donde se aplicaron. "

Esta investigación se desarrolló en el Departamento de Ge nética y Me joramie nto de Plantas del Instituto Nacional de Cie ncias Agrícolas (INCA ), provincia La Habana, Cuba, durante el período de 2002 al 2004, con el objetivo de evaluar el comportamie nto de suspensiones celulares de tres genotip os de Coffea canephora P. var. Robusta, para ello se procedió a estudiar la edad del callo más eficiente para el establecimiento del cultivo en medio líquido, para lo cual se evaluaron callos de 15, 21, 28, 35, 42, 49 y 56 días de cultivo. También se estudiaron diferentes medios de cultivos para la multip licación celular, MMC -1 con 0,2 mg/l de Kinetina y 0,5 mg/l de 2,4-D, empleado como medio control y el medio MMC -2 donde el 2,4-D fue sustituido por 0,7 mg/l de un extracto auxínico de origen bacteriano. Se determinaron los efectos de estos factores en la velocidad de desagregación, la coloración de la suspensión, así como en la concentración de células totales y meristemáticas. Se encontró que las suspensiones a partir de callos de 28 y 35 días de cultivo en medio sólido, presentaron mejor respuesta, dado el mayor número de células, velocidad de desagregación y adecuada coloración de la suspensión, destacándose los callos de estas edades como los más favorables para la inducción del cultivo en medio líquido, a partir de los genotip os estudiados. Se obtuvie ron mejores resultados con el medio de multip licación celular MMC -2.

La mayoría de los suelos tropicales y subtropicales son deficientes en fósforo biodisponible, por lo que el empleo de bacterias promotoras del crecimiento vegetal, principalmente las solubilizadoras de fosfato, pueden reducir el uso de fertilizantes químicos. El objetivo de este trabajo es ofrecer una panorámica actual acerca de los principales géneros y mecanismos de acción de las bacterias solubilizadoras de fosfatos (BSF), así como analizar su posible empleo en cultivos de importancia económica. La utilización de géneros bacterianos con mayores potencialidades de uso como Pseudomonas y Bacillus unido a aislados promisorios de Azospirillum y Herbaspirilum en cultivos como arroz y café permitiría reducir a largo plazo el uso de productos químicos en la agricultura, así como desarrollar estrategias agronómicas que preserven el medio ambiente. El éxito de estos inoculantes bacterianos depende de la selección de cepas autóctonas eficientes por tipo de suelo, su capacidad de colonizar la rizosfera y de mantener la actividad biológica.