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Development of two loquat [Eriobotrya japonica (Thunb.) Lindl.] linkage maps based on AFLPs and SSR markers from different Rosaceae species
Get PDFLoquat [Eriobotrya japonica (Thunb.) Lindl.] is a Rosaceae fruit species of growing interest as an alternative to the main fruit crops. However, only a few genetic studies have been carried out on this species. This paper reports the construction of the first genetic maps of two loquat cultivars based on AFLP and microsatellite markers from Malus, Eriobotrya, Pyrus and Prunus genera. An F1 population consisting of 81 individuals, derived from the cross between ‘Algerie’ and ‘Zaozhong-6’ cultivars, was used to construct both maps. A total of 111 scorable simple sequence repeat (SSR) loci resulted from the testing of 440 SSR primer pairs in the analyzed progeny and the SSR transferability to Eriobotrya was found to be 74% from apple, 58% from pear and 49% from Prunus spp. In addition, 183 AFLP polymorphic bands were produced using 42 primer combinations. The ‘Algerie’ map was organized in 17 linkage groups covering a distance of 900 cM and comprising 177 loci (83 SSRs and 94 AFLPs) with an average marker distance of 5.1 cM. Self-incompatibility trait was mapped at the distal part of the LG17 linkage group, as previously reported in Malus and Pyrus. The ‘Zaozhong-6’ map covered 870 cM comprising 146 loci (64 SSRs and 82 AFLPs) with an average marker distance of 5.9 cM. The 44 SSRs and the 48 AFLPs share in common by both maps were essentially collinear and, moreover, the order of the 75% of apple and pear SSRs mapped in Eriobotrya was shown to be consistent across the Maloideae subfamily. As a whole, these maps represent a useful tool to facilitate loquat breeding and an interesting framework for map comparison in the Rosaceae
Constitutive Expression of OsGH3.1 Reduces Auxin Content and Enhances Defense Response and Resistance to a Fungal Pathogen in Rice
Get PDFGH3 genes are main components of the hormonal mechanism regulating growth and development and, hence, are deeply involved in a broad range of physiological processes. They are implicated in hormonal homeostasis through the conjugation to amino acids of the free form of essential plant growth regulators such as indoleacetic and jasmonic acids. In this work, we showed that OsGH3.1 overexpression in rice caused dwarfism and significantly reduced both free auxin content and cell elongation. Functional classification of the transcriptomic profiling revealed that most genes involved in auxin biosynthesis and auxin signaling inhibition were induced and repressed, respectively. Many genes related to cell organization and biogenesis were also significantly downregulated. The survey also showed that, although the response to abiotic stresses was not clearly stimulated, OsGH3.1 overexpression did activate a significant number of defense-related genes. In successive bioassays, it was demonstrated that the resistance of rice plants to pathogen infection, evaluated with two different Magnaporthe grisea strains, was higher in the transformants overexpressing OsGH3.1. Taken together, these results indicate that OsGH3.1 overexpression reduces auxin content, inhibits cell growth and cell wall loosening, and enhances resistance to a fungal pathogen. Our results provide evidence that auxin homeostasis can regulate the activation of the defense response in rice
Efecto del bicarbonato sobre el crecimiento de los patrones de cítricos: mandarino Cleopatra, Poncirus trifoliata, Forner-Alcaide nº 030131 y Forner-Alcaide nº 030141
Get PDFSe ha llevado a cabo un ensayo en el que se estudia el crecimiento (altura y
peso fresco y seco del brote nuevo) de mandarino Cleopatra, Poncirus trifoliata y
dos de sus híbridos Forner-Alcaide (FA) FA 030131 y FA 030141 ante diferentes
concentraciones de bicarbonato. Estos patrones se cultivaron durante 84 días, en
macetas de 3L con arena silícea, regadas con soluciones nutritivas tipo Hoagland (20
μM de hierro) con diferentes concentraciones de bicarbonato sódico (0, 10 y 20 mM).
El patrón menos afectado por la concentración creciente de bicarbonato ha sido el
mandarino Cleopatra. Por el contrario el P. trifoliata fue el patrón en el que más se
redujo el crecimiento, tanto en altura como en peso fresco y seco del brote nuevo. El
efecto del bicarbonato fue diferente según el híbrido, el FA 030141 disminuyó más su
crecimiento con altas dosis de bicarbonato (20 mM), aunque estadísticamente no fue
significativo, mientras que en el FA 030131 el efecto reductor fue similar con ambas
dosis de bicarbonato (10 y 20mM)
Comparación de portainjertos en berenjena
Get PDFEl injerto sobre patrones resistentes puede solucionar algunos problemas de suelo
actuales ( Verticillium, Meloidogyne) o potenciales (Ralstonia solanacearum).
En España la práctica de injerto de berenjena está aún poco introducida, aunque se
va extendiendo. Aparte de los problemas por patógenos de suelo, el injerto permite
aumentar la calidad del fruto en un ciclo de cultivo largo.
Con este experimento se pretende evaluar la capacidad productiva de dos variedades
de berenjena semilarga injertadas sobre patrones pertenecientes a distintas especies y
compararlas con las de la planta sin injertar.
Se han utilizado dos variedades de berenjena semilarga y cuatro portainjertos.
La plantación se realizó en un invernadero con cubierta de malla y lámina de plástico
que el año anterior había tenido también berenjena y en la que se había detectado
Verticillium y Meloidogyne.
En varias ocasiones se ha estimado el vigor de las plantas y se han observado las que
tenían síntomas de enfermedad vascular (Verticicillium dahliae).
Al final del cultivo se han arrancado las plantas y se ha observado la presencia y cantidad
de nematodos. Se han medido los diámetros del tallo del patrón y la variedad por
debajo y por encima del injerto.
Los cuatro portainjertos ensayados han proporcionado una protección suficiente
frente a Verticillium y Meloidogvne. La afinidad de berenjena con todos ellos ha sido
buena, aunque con algunos presenta diferencias de diámetro de tallo.
La mayor producción se ha obtenido con los patrones Spirit y Beaufort
Discrimination Between Mild and Severe Citrus tristeza virus Isolates with a Rapid and Highly Specific Real-Time Reverse Transcription-Polymerase Chain Reaction Method Using TaqMan LNA Probes
Get PDFSevere isolates of Citrus tristeza virus (CTV) inducing seedling yellows (SY) and/or stem pitting (SP) in grapefruit or sweet orange are a major threat for the citrus industry worldwide. Identification of these CTV variants was achieved by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) using a general primer set and three TaqMan locked nucleic acids (LNA) probes targeting sequences characteristic of severe, mild (non-SY, non-SP), and T36-like isolates. Successful amplification was achieved from fresh or silica-desiccated CTV-infected samples and all isolates but one reacted with one or more probes. Standard curves using RNA transcripts homologous to the three probes allowed a reproducible quantitative assay, with a wide dynamic range of detection starting with 102 copies. RT-PCR assays with homologous and heterologous transcript RNA mixes demonstrated that each probe reacted only with its cognate sequence which was detected even at ratios below 2.5%. Analysis of 56 pathogenically distinct CTV isolates from 20 countries showed that mild isolates reacted only with the mild probe, whereas severe SP and SY isolates reacted with the severe-SP or the T36-like probes, respectively, and often with a second probe. This procedure can be useful to identify and control potentially dangerous CTV isolates in areas affected only by mild isolates
Potassium Sorbate Residue Levels and Persistence in Citrus Fruit as Detected by a Simple Colorimetric Method
No full textA colorimetric method that employed extraction of the macerated fruit, followed by a reaction with 2-thiobarbituric acid, was used to quantify potassium sorbate residues in citrus fruit. A recovery of more than 90% in oranges and lemons was obtained. Potassium sorbate residues determined by this method and a standard high-performance liquid chromatography (HPLC) method were similar. Residues were proportionate to the potassium sorbate concentration in the treatment solution. In oranges stored at 15 degrees C, following the potassium sorbate treatments, residues declined initially rapidly and later more slowly, until residues stopped declining after 6 days. A brief double-dip rinse in tap water applied immediately after immersion of lemons in a 2% (wt/vol) potassium sorbate removed more than 90% of the potassium sorbate residue. The influence of high-pressure water washing (HPWW) on potassium sorbate residues in potassium-sorbate-treated fruit was determined. Potassium sorbate residues were more effectively reduced by rinsing oranges than lemons
Quantitative estimation of plum pox virus targets acquired and transmitted by a single Myzus persicae
No full textThe viral charge acquired and inoculated by single aphids in a non-circulative transmission is estimated using plum pox virus (PPV). A combination of electrical penetration graph and TaqMan real-time RT-PCR techniques was used to establish the average number of PPV RNA targets inoculated by an aphid in a single probe (26,750), approximately half of the acquired ones. This number of PPV targets is responsible for a systemic infection of 20% on the inoculated receptor plants. No significant differences were found between the number of PPV RNA targets acquired after one and after five intracellular punctures (pd), but the frequency of infected receptor plants was higher after 5 pd. The percentage of PPV-positive leaf discs after just 1 pd of inoculation probe (28%/4,603 targets) was lower than after 5 pd (45.8%/135 x 10(6) targets). The methodology employed could be easily extended to other virus-vector-host combinations to improve the accuracy of models used in virus epidemiology
Evaluación del comportamiento del injerto simple y doble en melón
Get PDFUna de las razones por las que no se utiliza apenas el injerto en melón es la falta de afinidad entre los cultivares de tipo español (Piel de Sapo) y los patrones interespecíficos de Cucurbita (tipo Shintoza), que son las más tolerantes a Monosporascus y MNSV, capaces de producir el colapso. Los cultivares de tipo español, sin embargo, son plantas compatibles con portainjertos de la especie Cucumis melo (melón), pero de éstas, según nuestra experiencia, ninguna es capaz de soportar un ataque intenso de Monosporascus. El injerto, utilizando como patrón intermedio un cultivar con mejor compatibilidad, puede reducir los problemas que ocasiona la falta de afinidad. El injerto (simple y doble adosado) se hizo los días 26 y 28-03-07. La plantación se realizó el 17-04-07 en un campo que los 8-10 años anteriores había tenido sandía injertada. El marco de plantación era de 2,5 entre hileras y 0,675 y entre plantas (0,59 plantas/m2). La parcela elemental constaba de 8 plantas. La distribución del experimento fue de bloques al azar, con cuatro repeticiones. El injerto de Piel de Sapo directamente sobre Cucurbita híbrida, a diferencia de lo que
ha ocurrido en otras ocasiones, ha funcionado perfectamente, no observándose «miriñaque» en la unión del injerto de ninguna de las plantas, ni se ha producido clorosis o muerte prematura en ningún caso. Las plantas han producido perfectamente y han aguantado hasta el final. A pesar de ello, el injerto intermedio con el cultivar Sienne ha mejorado ligeramente la producción, el número de frutos, el aspecto de las parcelas y el porcentaje de plantas vivas al final del cultivo. Este cultivar, injertado sobre Strongtosa, ha tenido mejor comportamiento que el resto, lo cual indica que la unión del injerto, en este caso, es perfecta. La mayor producción comercial ha sido la de la combinación Piel de Sapo/Sienne/ Strongtosa (4,93 kg/m2), que ha sido significativamente mayor que la del resto de combinaciones. Todas las plantas injertadas han producido significativamente más (99% de probabilidad) que las no injertadas
Are the palms Washingtonia filifera and Chamaerops humilis suitable hosts for the red palm weevil, Rhynchophorus ferrugineus (Col. Curculionidae)?
No full textThe red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera, Curculionidae), is a widely distributed pest which has recently become the major pest of palms in the Mediterranean Basin. This weevil has been recorded on 19 different palm species, however, the host status of Washingtonia filifera and Chamaerops humilis remains unclear. The present study was carried out to check whether these species had either antixenotic or antibiotic mechanisms of resistance against this pest. Our results show that both W. filifera and C. humilis are resistant to R. ferrugineus. Resistance in W. filifera is based on antibiosis whereas in C. humilis resistance is based on antixenosis
Effects of antagonists and inhibitors of ethylene biosynthesis on maize root elongation.
No full textDuring the first days of development, maize roots showed considerable variation in the production of ethylene and the rate of elongation. As endogenous ethylene increases, root elongation decreases. When these roots are treated with the precursor of ethylene aminocyclopropane- 1-carboxylic acid (ACC), or inhibitors of ethylene biosynthesis 2-aminoethoxyvinyl glycine (AVG) or cobalt ions, the root elongation is also inhibited. Because of root growth diminishes at high or reduced endogenous ethylene concentrations, it appears that this phytohormone must be maintained in a range of concentrations to support normal root growth. In spite of its known role as inhibitor of ethylene action, silver thiosulphate (STS) does not change significantly the root elongation rate. This suggests that the action of ethylene on root elongation should occur, at least partially, by interaction with other growth regulators