Search

In order to conserve sugarcane germplasm, produce microbial disease-free material, detect resistance to diseases and pests, etc., in vitro propagation of sugarcane has been established in many commercial varieties. In this sense, the aim of this work was to analyze the efficiency of 2,4-dichlorophenoxyacetic acid (2,4D) and 3,6-dichloro -2- methoxybenzoic acid (Dicamba) to induce somatic embryogenesis and regeneration of plantlets from sugarcane varieties C26670, RB855546, V99245, V756, V781, V0050, CC8592, CC8475. For induction of embryogenic callus, leaf discs in tillering stage of 1 cm diameter and 2 mm thick, were inoculated on Murashige-Skoog, 1962 medium (MS), supplemented with 50 ml.l-1 coconut water, 30 g.l-1sucrose and two different treatments: 3 mg.l-1 2,4D or 6.63 mg.l-1 Dicamba, both of them in total darkness at 25 °C, during 1 month. For plant regeneration, embryogenic calli were transferred to ½ MS salts supplemented with coconut water 200 ml.l-1 and sucrose 60 g.l-1 and incubated under continuous light, 25 °C, for 2 months. The highest percent of embryogenic callus induction was obtained in media supplemented with Dicamba, an average of 70.83 % of embryogenic callus by variety, while in media with 2,4-D, 62.08 % of embryogenic callus was obtained by variety. An average of 89,00 % of plantlets was obtained from calli induced on media with Dicamba and an average of 66.12% of plantlets was obtained from calli induced on media supplemented with 2,4D. Using Dicamba it was possible to establish an efficient somatic embryogenesis protocol for these sugarcane varieties. Resumen El cultivo in vitro de la caña de azúcar ha sido establecido en muchas variedades comerciales con el propósito de producir material libre de enfermedades microbianas, conservar germoplasma, detectar resistencia a enfermedades y plagas, etc. En este sentido, el objetivo de este trabajo fue analizar la efectividad de las auxinas sintéticas ácido 2,4-diclorofenoxiacético (2,4D) y ácido 3,6-dicloro-2-metoxibenzoico (Dicamba), en la inducción del proceso de embriogénesis somática y la regeneración de vitroplántulas de distintas variedades de caña de azúcar (C26670, RB855546, V99245, V756, V781, V0050, CC8592, CC8475). Para esto se cultivaron discos de hojas en fase de macollamiento, de 1 cm de diámetro y 2 mm de grosor, en medio Murashige-Skoog, 1962 (MS) suplementado con 50 ml.l-1 agua de coco, 30 g.l-1 sacarosa y dos tratamientos diferentes: 3 mg.l-1 2,4-D ó 6.63 mg.l-1 Dicamba, ambos en completa oscuridad a 25°C, durante 1 mes. Los callos obtenidos se colocaron en medio de regeneración, conteniendo ½ sales MS, 200 ml.l-1 agua de coco y 60 g.L-1 sacarosa, incubándose bajo luz continua, 25°C, por 2 meses. El mayor porcentaje de callo embriogénico se obtuvo en medios suplementados con Dicamba un promedio de 70,83 % de callo embriogénico por variedad ; mientras que en los medios con 2,4D se obtuvo 62,08 % de callo embriogénico por variedad. Se obtuvo un promedio de 89,00 % de plantas regeneradas a partir de los callos obtenidos en medios con Dicamba y 66,12 % de plantas a partir de callos obtenidos en medios con 2,4D. Con el uso de Dicamba se estableció un sistema eficiente de embriogénesis somática para estas variedades de caña de azúcar.

La escaldadura foliar (EF) causada por Xanthomonas albilineans (Ashby) Dowson, es una de las enfermedades de mayor importancia en el cultivo de la caña de azúcar, Saccharum sp., ocasionando pérdidas estimadas entre 90-100% de la producción. El uso de la reacción en cadena de la polimerasa (por sus siglas en inglés pcR) como herramienta de diagnóstico de fitopa tógenos se incrementó a nivel mundial dada su rapidez, sensi bilidad y especificidad. Dada la importancia que tiene esta enfermedad en Venezuela, se llevó a cabo el diagnóstico de la bacteria a partir de plantas de caña de azúcar sintomáticas, empleando pruebas microbiológicas, bioquí micas y moleculares. Utilizando diversos métodos de purifi cación se obtuvieron aislados bacterianos, los cuales se some tieron a análisis fenotípicos y bioquímicos, así como a ensayos de pcR con iniciadores espe cíficos y las secuencias consenso repetitivas intragénicas de entero bacterias (siglas en inglés ERIc-pcR). con el método de macerado de hojas se obtuvieron 50 aislados, de los cuales 14 se selec cionaron por pruebas microbio lógicas y bioquí micas, de estos, sólo tres cepas fueron identi ficadas como X. albilineans. Este resultado se corroboró al obtener por pcR la banda esperada de 360 pb con los iniciadores específicos sólo en estos tres aislados. Finalmente, con la técnica de genotipificación ERIC-PCR se obtuvieron patrones de bandas para las bacterias identificadas como X. albilineans que no son similares a los descritos por otros autores en otras regiones del mundo. Este trabajo representa la primera genotipificación de aislados de X. albilineans en Venezuela Leaf scald caused by Xanthomonas albilineans, is one of the most important diseases in sugarcane, Saccharum sp., which causes serious economical losses estimated between 90-100%. The use of pcR as a diagnostic tool for plant pathogens has increased because of its speed, sensitivity and specificity. Given the importance of leaf scald in Venezuela, in this work we carried out the diagnosis of X. albilineans from symptomatic sugarcane plants, using microbiological, biochemical and molecular methods. Bacterial isolates were obtained using different methods of purification. These isolates were then subjected to phenotypic and biochemical analysis, PCR with specific primers and ERIc pcR. With the method of macerated leaves 50 isolates were obtained, out of which 14 were selected for biochemical tests. From these 14 isolates only three strains were identified as X. albilineans by microbiological and biochemical tests. These results were confirmed by PCR by obtaining the expected band of 360 bp using specific primers. Finally, the ERIc-pcR banding patterns obtained for the isolates identified as X. albilineans were found to be different to those described by other authors in other regions. This work represents the first genotyping assay of isolates of X. albilineans in Venezuela

Tissue culture techniques are routinely used for mass propagation and the establishment of disease free stock material. Virtually all pot type Anthuriums available in the market today are produced by tissue culture. In this chapter, we describe an efficient protocol to obtain Anthurium andreanum cv Rubrun vitro plants through micropropagation and organogenesis. Seeds from plant spadixes were germinated on MS medium supplemented with 0.5 mg/L BA. Micro-cuttings from in vitro germinated seedlings were subcultured on MS medium containing 2 mg/L BA and 0.5 mg/L NAA. Four-week-old in vitro plants obtained from microcuttings, showed callus proliferation at the stem base. The development of shoots and plantlets was observed from callus tissue. We also describe a detailed method for the histological analysis of callus tissue and a vitro plants acclimatization protocol.

Tissue culture techniques are routinely used for mass propagation and the establishment of disease free stock material. Virtually all pot type Anthuriums available in the market today are produced by tissue culture. In this chapter, we describe an efficient protocol to obtain Anthurium andreanum cv Rubrun vitro plants through micropropagation and organogenesis. Seeds from plant spadixes were germinated on MS medium supplemented with 0.5 mg/L BA. Micro-cuttings from in vitro germinated seedlings were subcultured on MS medium containing 2 mg/L BA and 0.5 mg/L NAA. Four-week-old in vitro plants obtained from microcuttings, showed callus proliferation at the stem base. The development of shoots and plantlets was observed from callus tissue. We also describe a detailed method for the histological analysis of callus tissue and a vitro plants acclimatization protocol.

The genetic stability of Solanum tuberosum L. cv. Désirée plantlets obtained from embryogenic cell suspension cultures that were induced from mixoploidy calli tissue with abundant binucleated cells was analyzed. Plants regenerated from these tissues showed an euploid number of chromosomes (2n=4x=48). This result indicates that in this system, euploid cells were selected to go through a somatic embryogenesis process and plant regeneration. Genotype stability of the regenerated plants was screened by RAPD analysis. The results indicated that the new plant population was highly homogeneous Se analizó la estabilidad genética de plántulas de Solanum tuberosum L. cv. Désirée obtenidas a partir del cultivo de células embriogénicas en suspensión, las que fueron inducidas a partir de callos mixoploides con abundantes células binucleadas. Las plantas regeneradas a partir de estos tejidos presentaron un número euploide de cromosomas (2n=4x=48). Este resultado indica que en este sistema las células euploides fueron seleccionadas para seguir el proceso de embryogenesis somática y regeneración de plantas. La estabilidad genotípica de las plantas regeneradas fue evaluada mediante marcadores RAPD. Los resultados indican que las nuevas poblaciones de plantas son altamente homogéneas Analisou-se a estabilidade genética de plântulas de Solanum tuberosum L. cv. Désirée obtidas a partir do cultivo de células embriogênicas em suspensão, as que foram induzidas a partir de calos com ploidia mista com abundantes células binucleadas. As plantas regeneradas a partir de estes tecidos apresentaram um número euplóide de cromossomos (2n=4x=48). Este resultado indica que neste sistema as células euplóides foram selecionadas para seguir o processo de embriogênese somática e regeneração de plantas. A estabilidade genotípica das plantas regeneradas foi avaliada mediante marcadores RAPD. Os resultados indicam que as novas populações de plantas são altamente homogêneas

La micropropagación y la organogénesis de Aster ericoides cultivar "Monte Cassino" fueron establecidas a partir del cultivo de yemas, microesquejes y hojas obtenidos de plantas de 2 meses de edad mantenidas en condiciones de vivero. Las yemas y microesquejes fueron cultivados en medios MS suplementados con 1mg·l-1 de cinetina (K) y 0,5mg·l-1 de ácido indolacético (AIA), obteniendo a los 2 meses de cultivo un promedio de 4,68 brotes a partir del cultivo de microesquejes y de 2,64 brotes a partir del cultivo de yemas. El proceso de organogénesis fue inducido utilizando explantes de hojas de plantas cultivadas in vitro en medios MS suplementados con benciladenina (BA) y ácido naftaleno-acético (ANA). El proceso de organogénesis directa fue observado en medio MS suplementado con 0,5mg·l-1 BA y 0,5mg·l-1 ANA, obteniendo un número promedio de 1 brote por explante, a los 30-45 días de cultivo. La organogénesis indirecta se observó a partir de callos cultivados en medios suplementados con las mayores concentraciones de BA, obteniéndose el mayor índice de formación de brotes (1,16) en el medio suplementado con 5mg·l-1 BA y 0,5mg·l-1 ANA, a los 6 meses de cultivo. El mayor porcentaje de aclimatación (80%) fue observado en plantas obtenidas a partir del proceso de organogénesis en sustratos de tierra negra. La micropropagación a través del cultivo de microesquejes resultó el sistema de propagación in vitro más eficiente para Aster ericoides cultivar "Monte Cassino". Micropropagation and organogenesis were established for Aster ericoides cv. "Monte Cassino". Buds and micro cuttings were obtained from 2 months old greenhouse grown plants and cultured on an MS medium supplemented with kinetin (K) 1mg·l-1 and indol acetic acid (IAA) 0,5mg·l-1. Two months later, an average of 4.68 shoots from micro cuttings culture and 2.64 shoots from buds culture were obtained. Organogenic processes were induced using leaf explants obtained from in vitro plants. These explants were cultured on an MS medium supplemented with bencyladenine (BA) and naphthalene acetic acid (NAA). Direct organogenesis was observed on a medium supplemented with BA 0.5mg·l-1 and NAA 0.5mg·l-1. After 30-45 days, an average of one shoot per explant was obtained. Indirect organogenesis was observed 15 days after culture initiation in almost all the culture media. After six months, the highest shoot formation index (1.16) was obtained on an MS medium supplemented with BA 5mg·l-1 and NAA 0.5mg·l-1. Plants regenerated by organogenesis were transferred to pots and a rate of 80% of plant acclimatization was obtained. Micropropagation from micro cuttings was the most efficient in vitro propagation system for Aster ericoides cv "Monte Cassino". A micropropagação e a organogênese de Aster ericoides Cultivar "Monte Cassino" foram estabelecidas a partir do cultivo de gemas, microestaquias e folhas obtidas de plantas de 2 meses de idade mantidas em condições de viveiro. As gemas e microestaquias foram cultivadas em meios MS suplementados com 1mg·l-1 de cinetina (K) e 0,5mg·l-1 de ácido indolacético (AIA), obtendo aos 2 meses de cultivo uma média de 4,68 brotes a partir do cultivo de microestaquias e de 2,64 brotes a partir do cultivo de gemas. O processo de organogênese foi induzido utilizando explantes de folhas de plantas cultivadas in vitro em meios MS suplementados com benziladenina (BA) e ácido naftaleno acético (ANA). O processo de organogênese direta foi observado em meio MS suplementado com 0,5mg·l-1 BA e 0,5mg·l-1 ANA, obtendo um número médio de 1 brote por explante, aos 30-45 dias de cultivo. A organogênese indireta se se observou a partir de calos cultivados em meios suplementados com as maiores concentrações de BA, obtendo-se o maior índice de formação de brotes (1,16) no meio suplementado com 5mg·l-1 BA e 0,5mg·l-1 ANA, aos 6 meses de cultivo. A maior porcentagem de aclimatação (80%) foi observado em plantas obtidas a partir do processo de organogênese em substratos de terra negra. A micropropagação através do cultivo de microestaquias resultou o sistema de propagação in vitro mais eficiente para Aster ericoides cultivar "Monte Cassino".