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El presente estudio se realizó en el Instituto Nacional de Ciencias Agrícolas de Cuba, con el objetivo de evaluar el efecto de diferentes concentraciones del compuesto bacteriano CB-1 sobre el crecimiento y desarrollo in vitro de tres clones seleccionados de cafeto, var. Robusta, así como valorar la posible sustitución de la auxina AIA en el medio de cultivo establecido para la multiplicación del cafeto, donde se realizaron ensayos durante la fase de aclimatización de las vitroplantas. Se estudiaron diferentes tratamientos. Como testigo se empleó el medio de multiplicación establecido convencionalmente, mientras que los otros tres tratamientos consistieron en sustituir el AIÁ del medio por el CB-1 a diferentes concentraciones (0.5; 1.0 y 2.0 mg.L-1). Durante la aclimatización, se estudió el efecto del biopreparado (sólido y líquido), a través de la exposición del sistema radical de las plántulas a una concentración de 20 mg/L del compuesto por 30 minutos. Se evaluaron las variables: número de explantes vivos, altura de la vitroplanta (cm), número de brotes, número de pares de hojas, porcentaje de plantas enraizadas y contenido de proteínas totales y fenoles (mg/g tejido). Como resultado se detectaron variaciones en la respuesta de los clones estudiados, así como en los indicadores evaluados, obteniéndose mayor capacidad de respuesta en el clon M-229 y con concentraciones de 0.5 y 1.0 mg.L-1 de CB-1. Se obtuvo mayor efectividad con el CB-1 en estado líquido durante la aclimatización de las vitroplantas. Se demostró la factibilidad del empleo del nuevo biopreparado en la estimulación del crecimiento vegetal.

Copyright of Cuban Journal of Biological Sciences / Revista Cubana de Ciencias Biológicas is the property of Cuban Journal of Biological Sciences / Revista Cubana de Ciencias Biologicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the present article is to show the relevance of «Experimental Methods in Microbiology and Virology» subject in the Professional Education Process. To this aim, we will analyze its contribution in program «D» to the comprehensive education of the microbiologist. Different Methodological Strategies were designed and executed which covered from subjects groups to methodological workshops, as well as compilation and analysis of the results of surveys made to students. All these elements allowed perceiving a greater comprehensive education of the students, particularly their acquisition of more abilities through the integration of theoretical knowledge with the practical one, together with the strengthening of human values. All this promotes the formation of professionals in the fields of services, production and scientific research according to the priorities of the country. [ABSTRACT FROM AUTHOR]

This study aimed to evaluatein vitrografting ofTheobroma cacaowhere 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 toex vitroconditions. 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%. Overall, side grafting with axillary buds is the most appropriate method for cacao micrografting. This method can be used for clonal propagation and for the establishment ofin vivoand/orin vitrocacao germplasm collection. [ABSTRACT FROM AUTHOR]

Copyright of Cuban Journal of Biological Sciences / Revista Cubana de Ciencias Biológicas is the property of Cuban Journal of Biological Sciences / Revista Cubana de Ciencias Biologicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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, México. 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. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM PUBLISHER]

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The identification of rhizobacteria with potential for the biocontrol and plant growth promotion is of great interest for the improvement of rice crop (Oryza sativa L.) in Cuba. This work was aimed at identifying native fluorescent pseudomonas isolates with antagonistic activity against Curvularia pallescens and Curvularia trifolii. The results showed that all the isolates selected had antagonistic effect against the fungal isolates tested, showing inhibition percentages ranging from 49% to 83%. They were classified as Pseudomonas putida (14 of them) and Pseudomonas fluorescens (three). In general, it suggests the potential of these rhizobacteria as biocontrol agents against fungal pathogens in rice crop. [ABSTRACT FROM AUTHOR]

Sooty molds (Capnodium spp.) affect coffee seedlings during acclimatization. The objective of this study was to evaluate the effect of a biological product obtained from Burkholderia cepacia for control of this disease. Different concentrations of the product (50-250 mg L-1) were used to evaluate its effect on mycelial growth inhibition of Capnodium spp., as well as the effect of the biological product on infection index, growth (pairs of leaves, height and dry weight), total protein content, phenolics, and seedling survival. The results showed growth inhibition of Capnodium spp. up to 79.3% (200 mg mL-1). Total control of the disease was obtained(150 mg L-1) on clone M-28, and 95 and 90% on clones M-229 and K-234 (150-200 mg mL-1), respectively. In addition, it was observed a better behavior of growth indicators: proteins, phenolics, and seedling survival. The results corroborated the feasibility of the use of this biological product for control of sooty molds in coffee seedlings during acclimatization. [ABSTRACT FROM AUTHOR]

The article offers information on the use of rhizobacteria as biocontrol agents in crops of economic importance. It is mentioned that the presence of rhizosphere in bacteria can be isolated and inoculated to several crops inducing positive effect on plants. Biological control of pathogens is one important method for beneficial effect expressed in rhizobacteria. The three basic characteristics expressed by rhizobacteria include the ability to produce antibiotics, siderophores, volatile compounds among other metabolites. Rhizobacteria induce systemic resistance against fungal, bacterial and viral plants.

The objective of this work was to determine the antagonistic effect of three strains of fluorescent Pseudomonas spp. against a pathogenic strain of A. solani isolated from potato. Two culture media were tested in in vitro dual culture assays to determine the antagonistic effect of the Pseudomonas strains, the preventive action, and the fungistatic effect of the bacterial strains and of their metabolites. In each experiment, the treatments were compared by analysis of variance and Tukey's test; in addition, the percentages of the preventive action and the fungistatic effect were tested according to the comparison of proportions. Pseudomonas spp. strains markedly inhibited the growth of the pathogen; Pseudomonas protegens Pf-5 excelled for being the best in all the tests performed, besides the apparent mycoparasitism. These results showed that this latter strain could be promising for the biological control of this pathogen in the potato crop. [ABSTRACT FROM AUTHOR]

Potyvirus genus is one of the most studied among the plant virus group. It is worldwide distributed and affects different hosts and solanaceus crops. The aims of this work was to determinate the potyvirus incidence in agroeconomical important solanaceus crop in the west zones of Cuba. 1120 young leaves of Solanum lycopersicum, Capsicum annuum and Nicotiana tabacum were collected and analyzed by indirect ELISA, using monoclonal antibodies. Among 34 and 75 % of the plant material was positive. Highest incidence value was detected on San Juan y Martínez and San Antonio de los Baños districts while the lowest values was registered in Güira de Melena [ABSTRACT FROM AUTHOR]

The article presents a study on the use of antagonistic microorganisms to control postharvest diseases of fruits. It states that antagonistic microorganisms have been utilized as biological control agents for several postharvest diseases of fresh fruits. It discusses that to properly use this type of microorganism, it is essential to understand the action mechanisms involved in biocontrol activities that would allow a more secure development of the application processes and a base to choose new and efficient strains.