A Review of the Studies and Interactions of Pseudomonas syringae

Wheat is affected by some pathovars of Pseudomonas syringae and by other Pseudomonas species. Of these, P. syringae pv. syringae is the major one responsible for reduction. Recent studies have been made to characterize and identify the pathogen and to determine its aggressiveness and the pattern of colonization in seed and its effects on seed yield, yield components, and source-sink relationships during postanthesis. It was found that the reduction in the aerial biomass production is the best way to evaluate the aggressiveness of this bacterium, and the spray inoculation is good tool to make evaluations at seedling stage. The characterization of bacteria fingerprintings with molecular markers such as RAPD-PCR, ERIC, and REP-PCR is available. Genomic evolution has been elucidated with next-generation genome sequencing. Also, the colonization pattern shows that, early on, microcolonies are frequently detected in the aleurone layer, later in the endosperm and finally close to the crease and even in some cells of the embryo itself. In the wheat cultivars Seri M82 and Rebeca F2000 seed yield and its components are negatively affected. In general, P. syringae pv. syringae reduces the plant height, seed yield, and yield components, as well as the growth of most organs. When this bacterium attacks, the stems are the predominant sink organs and the leaf laminae and panicles are the predominant source organs

Germinación de conidios de Botryosphaeria dothidea Mough.: Fr (Ces. & De Not.) y alteraciones histológicas en tallos de pitahaya (Hylocereus undatus) (Haworth) Britton & Rose

Conidial germination of Botryosphaeria dothidea (anamorph: Fusicoccum) in sterile distilled water and 1% sterile dextrose solutionwas evaluated at 4, 6, 12, 24 and 36 h after incubation. Also, it was described the anatomical changes on pitahaya stems induced by this fungus, collected in the field and artificially inoculated in the laboratory. Conidial germination was less than 30% in water and it was improved when 1% dextrose was added to the water. In 1% dextrose solution the germination was 90% after 4h of incubation and 100% at 6 h. Pathogen germ tubes had entered through wounds and sometimes through stomata and hyphae colonized intra and intercellularly in the parenchyma-chlorenchyma tissues. On naturally and artificially diseased stems the main alterations were: destruction of cuticle, hyperplasia of epidermal and collenchymatous hypodermal cells and conform the advance of the pathogen a layer of lignified periderm was formed surrounding the damaged tissues; however, it couldn't stop the advance of the pathogen and the cells that surrounded the lesion suffered necrosis.Conidial germination of Botryosphaeria dothidea (anamorph: Fusicoccum) in sterile distilled water and 1% sterile dextrose solutionwas evaluated at 4, 6, 12, 24 and 36 h after incubation. Also, it was described the anatomical changes on pitahaya stems induced by this fungus, collected in the field and artificially inoculated in the laboratory. Conidial germination was less than 30% in water and it was improved when 1% dextrose was added to the water. In 1% dextrose solution the germination was 90% after 4h of incubation and 100% at 6 h. Pathogen germ tubes had entered through wounds and sometimes through stomata and hyphae colonized intra and intercellularly in the parenchyma-chlorenchyma tissues. On naturally and artificially diseased stems the main alterations were: destruction of cuticle, hyperplasia of epidermal and collenchymatous hypodermal cells and conform the advance of the pathogen a layer of lignified periderm was formed surrounding the damaged tissues; however, it couldn't stop the advance of the pathogen and the cells that surrounded the lesion suffered necrosis

Germinación de conidios de Botryosphaeria dothidea Mough.: Fr (Ces. & De Not.) y alteraciones histológicas en tallos de pitahaya (Hylocereus undatus) (Haworth) Britton & Rose

Conidial germination of Botryosphaeria dothidea (anamorph: Fusicoccum) in sterile distilled water and 1% sterile dextrose solution was evaluated at 4, 6, 12, 24 and 36 h after incubation. Also, it was described the anatomical changes on pitahaya stems induced by this fungus, collected in the field and artificially inoculated in the laboratory. Conidial germination was less than 30% in water and it was improved when 1% dextrose was added to the water. In 1% dextrose solution the germination was 90% after 4h of incubation and 100% at 6 h. Pathogen germ tubes had entered through wounds and sometimes through stomata and hyphae colonized intra and intercellularly in the parenchyma-chlorenchyma tissues. On naturally and artificially diseased stems the main alterations were: destruction of cuticle, hyperplasia of epidermal and collenchymatous hypodermal cells and conform the advance of the pathogen a layer of lignified periderm was formed surrounding the damaged tissues; however, it couldn't stop the advance of the pathogen and the cells that surrounded the lesion suffered necrosis.Se evaluó la germinación de conidios de Botryosphaeria dothidea (anamorfo: Fusicoccum) en agua destilada estéril y en una solución de dextrosa 1% a las 4, 6, 12, 24 y 36 h de incubación. También, se describieron los cambios anatómicos en tallos de pitahaya inducidos por este hongo, tanto aquellos naturalmente infectados en campo como inoculados artificialmente en laboratorio. La germinación de conidios en agua estéril solo alcanzó el 30%, mientras que la adición de dextrosa al 1% mejoró la germinación. En una solución de dextrosa al 1% la germinación a las 4 h fue de 90% y del 100% a las 6 h. Los tubos germinativos del hongo penetraron a través de las heridas y algunas veces a través de los estomas y se multiplicaron inter e intracelularmente en los tejidos del parénquima-clorénquima. En tallos enfermos natural y artificialmente, las principales alteraciones fueron: destrucción de la cutícula, hiperplasia de las células epidermales e hipodermales colenquimatosas. Conforme el avance del patógeno se formó una capa de peridermis lignificada que rodeó el tejido dañado; sin embargo, no se detuvo el avance del patógeno y las células que rodeaban la lesión se necrosaron.Fil: Valencia-Botín, Alberto J.. Universidad de Guadalajara (México)Fil: Cisneros-López, María E..Fil: Ruíz-Sánchez, Esaú. Instituto Tecnológico de Conkal (México

Disponibilidad de polen y producción de semilla en sorgo (Sorghum bicolor) bajo diferente proporción de plantas macho y hembra en valles altos de México

The availability of pollen in sorghum (Sorghum bicolor [Moench] L.) production is generally not considered a restrictive factor due to the sorghum self-pollination process. However, during the cross pollination process restrictions could play a role that depends on the distance of the pollen source, the proportion of male to female plants and the sowing date. The objective of this experiment was to establish the relationship between pollen production, deposition and season variations in seed set under different proportion male:female rows. The A9/B9-line was sowed on May 3, June 10, 2005, with the proportions: 2:4, 2:6 andon April 3, 2006 with proportions of 2:12 and 2:16 in Montecillo, State of Mexico. In isolines, number of flowers per panicle was measured at the ending of flowering. During all the flowering period, pollen production was quantified in male line and pollen deposition on female line rows using passive traps. During harvest the length of panicle was measured, quantified by the number of seeds per panicle and seed set was estimated. The pollen availability, synchrony floral, duration of phenological stage and seed production were influenced by sowing date and varied with the male and female rows. Precocity was observed in A9 female isoline more than B9-male line in three sowing dates. Number of pollen grains and seeds declined proportionally with increasing distance from the pollen source, but the rate was different for each proportion. The pollination was associated more to the size of pollen source and its dispersion than with population of female plants.La disponibilidad de polen en la producción de sorgo (Sorghum bicolor [Moench] L.) generalmente no se considera un factor restrictivo debido al proceso de auto polinización; sin embargo durante la polinización cruzada diversas restricciones como la distancia de la fuente del polen, proporción de plantas macho y hembra y la fecha de siembra, podrían jugar un papel importante. El objetivo de este experimento fue establecer la relación entre la producción, deposición y cambios estacionales de polen en la producción de semilla; utilizando diferentes proporciones de surcos masculinos:femeninos. La línea A9/B9 se sembró el 3 de mayo y 10 de junio de 2005 con las proporciones 2:4, 2:6 y el 3 de abril de 2006 con los proporciones 2:12 y 2:16 en Montecillo, Estado de México. El isolíneas, se midió el número de flores por panícula al final de la floración. Durante todo el período de floración, se cuantificó la producción de polen en línea masculina y la deposición de polen en surcos femeninos, utilizando trampas pasivas. En la cosecha se midió la longitud de la panícula, cuantificado por el número de semillas por panícula y la producción estimada de semillas. La disponibilidad de polen, sincronía floral, duración del estado fenológico y la producción de semillas fueron influenciadas por la fecha de siembra y varió por los surcos masculinos y femeninos. Se observó precocidad en la isolínea femenina A9 más que en la línea masculina B9 para las tres fechas de siembra. El número de granos de polen y semillas declinó proporcionalmente según se incrementó la distancia de la fuente de polen, pero la tasa fue diferente para cada proporción. La polinización se asoció más con el tamaño de la fuente de polen y su dispersión más que con la población de plantas femeninas.Fil: Cisneros López, María E..Fil: Valencia Botín, Alberto J.. Universidad de Guadalajara (México)Fil: Estrada-Girón, Yokiushirdhilgilmara. Universidad de Guadalajara (México

L'ÉVOLUTION DU HINDI DANS UNE AIRE MULTILINGUE

International audienceDie Studie beschäftigt sich mit der Entwicklung der Hindisprache in der mehrsprachiger Umwelt, die typisch für den Sübindischen Kontinenten ist. Nach einer kurzen Darstellung der Klassifizierung des Hindis in der indogermanischen Familie und der Hauptmerkmale der diakronischen Entwicklung der Sprache aus dem Sanskrit, werden die Kontaktphänomenen mit der dravidischen Sprachen, die Entwicklung von Dialekten erörtert, deren einige einzige Sprach sind, Zweisprachigkeit, Diglossie, Kontaktsprachen und Pidgin.The study bears on the evolution of the Hindi language in the multilingual environment which characterizes the Indian subcontinent. After a brief presentation of the classifications of Hindi within the Indo-Aryan family and of the main features of the evolution of the language out of Sanskrit, the main phenomenons of contact with Dravidian are treated, as well as the development of dialects, some of which are linguistically full fledged languages, bilinguism and diglossia, contact languages and pidgins.L'étude porte sur l'évolution du hindi dans l'environnement multilingue caractéristique du sous continent indien : après une brève présentation des classifications du hindi dans la famille indo-aryenne et des principaux traits de l'évolution diachronique de la langue à partir du sanskrit, sont abordés les phénomènes de contact avec le dravidien, déploiement des « dialectes », dont certains sont linguistiquement des langues à part entière, bilinguisme et diglossie, langues de contact et pidgins.