El Calafate (Berberis microphylla G. Forst.), es una especie endémica de Los Andes Patagónicos de Chile y Argentina, con potencial de cultivo para la agroindustria. Un aspecto que pudiere ser restrictivo para su establecimiento y producción es la roya del Calafate, cuya última referencia en Chile data del 1945. El objetivo de este estudio fue identificar y actualizar la prevalencia de esta roya en la Región de La Araucanía, Chile. La identificación morfológica fue consistente con Puccinia meyeri-albertii P. Magn, determinación corroborada por el Centre for Agricultural Bioscience International (CABI) y registrada con el número IMI-50016. La secuencia amplificada desde el 28S del ADN ribosomal (accession KY555071), tuvo una identidad de 97% con otras seis especies de Puccinia. El análisis de relaciones genéticas de P. meyeri-albertii, representadas en un árbol filogenético, generó amplias divergencias sobre las substituciones de nucleótidos respecto de las otras royas comparadas en este estudio; es de consignar que en la base de datos del NCBI no se dispone secuencias nucleotídicas para este hongo. A través de prospecciones realizadas durante la temporada 2011-2012 en un huerto experimental de calafate, la incidencia y severidad de P. meyeri-albertii fueron respectivamente: 24,70% (rango 4,72%-36,90%) y 2,97 (2,15 – 3,30, rango de área afectada) en hojas; mientras que en frutos fue de 13,78 % (1,13-23,84%) y 2,40 (2,01-2,78, rango de área afectada). Al respecto, sería conveniente generar información en aspectos moleculares, epidemiológicos y de control de este patógeno, como también evaluar el nivel de infección en ecotipos de calafate y especies de Berberis que crecen en diversas condiciones edafoclimáticas.
Kiwifruit bleeding sap samples, collected in Italian and Chilean orchards from symptomatic and asymptomatic plants, were evaluated for the presence of Pseudomonas syringae pv. actinidiae, the causal agent of bacterial canker. The saps were sampled during the spring in both hemispheres, before the bud sprouting, during the optimal time window for the collection of an adequate volume of sample for the early detection of the pathogen, preliminarily by molecular assays, and then through its direct isolation and identification. The results of molecular analyses showed more effectiveness in the P. syringae pv. actinidiae detection when compared with those of microbiological analyses through the pathogen isolation on the nutritive and semiselective media selected. The bleeding sap analyses allowed the isolation and identification of two hypersensitive response (HR) negative and hypovirulent P. syringae pv. actinidiae strains from different regions in Italy. Moreover, multilocus sequence analysis (MLSA) and whole genome sequence (WGS) were carried out on selected Italian and Chilean P. syringae pv. actinidiae virulent strains to verify the presence of genetic variability compared with the HR negative strains and to compare the variability of selected gene clusters between strains isolated in both countries. All the strains showed the lack of argK and coronatine gene clusters as reported for the biovar 3 P. syringae pv. actinidiae strains. Despite the biologic differences obtained in the tobacco bioassays and in pathogenicity assays, the MLSA and WGS analyses did not show significant differences between the WGS of the HR negative and HR positive strains; the difference, on the other hand, between PAC_ICE sequences of Italian and Chilean P. syringae pv. actinidiae strains was confirmed. The inability of the hypovirulent strains IPV-BO 8893 and IPV-BO 9286 to provoke HR in tobacco and the low virulence shown in this host could not be associated with mutations or recombinations in T3SS island.
Este proyecto de carácter nacional busca entregar un espacio en la red donde se pueda encontrar las herramientas necesarias para realizar vigilancia, pronóstico, investigación y control de la plaga emergente Drosophila suzukii. Busca articular información técnica, proyectos, artículos de investigación e investigadores. Además entrega información en tiempo real a los beneficiarios, productores, investigadores, asesores, sobre las detecciones validadas a nivel comunal.
Plant bacterial diseases are routinely managed with scheduled treatments based on heavy metal compounds or on antibiotics; to reduce the negative environmental impact due to the use of such chemical compounds, as pollution or selection of antibiotic resistant pathogens, the integrated control management is required. In the frame of a sustainable agriculture the use of bacterial antagonists, biological agents, plant defence response elicitors or resistant host plant genotypes are the most effective approaches. In this work, cold atmospheric pressure plasma (CAP) was applied to sterile distilled water, inducing the production of a hydrogen peroxide, nitrite and nitrate, and a pH reduction. In particular, an atmospheric pressure dielectric barrier discharge (DBD) has been used to produce plasma activated water (PAW), that was firstly assayed in in vitro experiments and then in planta through application at the root apparatus of tomato plants, against Xanthomonas vesicatoria (Xv), the etiological agent of bacterial leaf spot. Moreover, the transcription abundance of five genes related to the plant defense was investigated in response to PAW treatment.
PAW did not show direct antimicrobial activity against Xv in in vitro experiments, but it enhanced the tomato plants defenses. It was effective in reducing the disease severity by giving relative protections of ca. 61, 51 and 38% when applied 1 h, 24 h and 6 days before the experimental inoculation, respectively. In addition, the experiments highlighted the pal gene involvement in response to the PAW treatments and against the pathogen; its transcription levels resulted significantly high from 1 to 48 h until their decrease 192 h after PAW application.
Actualmente, ante el escenario de cambio climático la fruticultura chilena enfrenta importantes desafíos, siendo los más críticos la adaptabilidad de las plantas a las nuevas condiciones edafoclimáticas y la escasez de mano de obra capacitada (FIA, 2017). Para afrontar el problema, el sector frutícola ha recurrido a diversas estrategias, entre ellas, la introducción de nuevas variedades con mejor adaptabilidad, bajos requerimientos de horas frío, alto valor agregado y mayor productividad, junto con la adopción de nuevas tecnologías y la diversificación de las especies en los huertos, de manera de asegurar la mano de obra durante toda la temporada.
El kiwi (Actinidia spp.) es uno de los cultivos que se perfila como una atractiva alternativa productiva por su creciente demanda mundial (3 millones ton), donde Chile se caracteriza por ser el tercer exportador (179.833 ton) después de Italia y Nueva Zelanda (FAO, 2017). Las regiones del Maule y OHiggins representan cerca del 90% de la superficie nacional (respectivamente 50,8% y 37%), siendo la variedad Hayward (pulpa verde) tradicionalmente la más cultivada. Dadas las condiciones de alta demanda y mejores precios internacionales, en la última década se han introducido nuevas variedades de pulpa amarilla, las cuales presentan mayor rentabilidad en comparación a ´Hayward. En particular, la Región de OHiggins con 3.376 ha de kiwi en producción (equivalentes a 73.554 ton), se destaca por la mayor superficie de variedades de pulpa amarilla (50,4% del total nacional; 622 ha) (ASOEX, 2017). Sin embargo, estas últimas son conocidas por su mayor susceptibilidad al cancro bacteriano (Pseudomona syringae pv. actinidiae; Psa) y a eventos climáticos adversos (e.g. heladas y lluvias primaverales), por lo que se requiere adoptar nuevas estrategias de manejo agronómico.
La experiencia internacional menciona a los sistemas de cobertura como una óptima alternativa para contener y disminuir la presencia del cancro bacteriano del kiwi, reducir el riesgo por adversidades climáticas y mejorar la producción de los huertos. Bajo las condiciones regionales, existen experiencias en el uso de sistemas de cobertura en manzano, cerezo y vid, mientras que en kiwi sólo se han realizado algunas aproximaciones, lo cual constituye una oportunidad para aumentar la eficiencia productiva y la rentabilidad del sector frutícola local.
Objetivo general
Aumentar la competitividad de los productores de kiwi mediante la generación de directrices tecnológicas para el uso de sistemas de cobertura foto-selectivas en la Región de OHiggins
Cumplo un rol de Investigador Asociado.
Which are the molecular and physiological mechanisms involved in priming and defense activation in cherry plants upon Pss infection?
Are these mechanisms differentially activated between susceptible and resistance cherry varieties?
Do susceptible and resistance cherry varieties present a differential priming under different PRIs exposure?
Even more, the increasing of aridity and drought in the North of the country, the advancing desert toward the South and a
reduction in water resources in the central zone of Chile, are expected along the XXI century. In this scenario of climate change, other question arises: Which are the molecular and physiological mechanisms involved in priming and defense activation in cherry plants upon Pss infection combined with water deficit?
Through this proposal, we intend to answer to these questions, in order to establish the basis for optimize the control of the bacterial canker in cherry fruit tree, by strategies that provide for the use of resistance inductors.
We propose two hypotheses: a) Cherry cultivars with differential susceptibility to bacterial canker, caused by Pseudomonas syringae pv. syringae, present genetic differences in the molecular machinery of plant immunity; b) Pseudomonas syringae pv. syringae infection is enhanced by water restriction due to an alteration of the molecular machinery of plant immunity.
The aims of this proposal is to obtain a better understanding of the plant-pathogen molecular interactions of sweet cherry bacterial canker in relationship with water deficit, using mainly omics strategies.
The efficacy of the bio-fungicide Amylo-X®, based on Bacillus amyloliquefaciens subsp. plantarum (Bap) strain D747, was evaluated in vivo against Pseudomonas syringae pv. actinidiae (Psa), the causal agent of kiwifruit bacterial canker disease. By in vivo tests, under controlled conditions, Amylo-X® reduced the disease severity caused by Psa in Actinidia chinensis var. deliciosa and in A. chinensis var. chinensis plants providing a protection of about 50 and 70%, respectively. By in vivo trials Bap strain D747 was able to colonize A. chinensis var. chinensis female flowers up to 96 h (ca. 105-7 CFU flower‑1) and to persist on A. chinensis var. deliciosa leaves up to 4 weeks (ca. 104-6 CFU cm‑2), during 2017 and 2018 in northern and central Italy (Emilia Romagna and Lazio Regions). In particular, on flowers, Bap strain D747 caused a significant reduction in the Psa population as compared to the control samples. In Lazio Region field trials, during 2018, Amylo-X® reduced the disease severity on leaves of A. deliciosa plants with a protection up to 40%. The strain Bap D747 sensitivity to streptomycin sulphate was confirmed by applying the most commonly used concentration in those countries where antibiotics are allowed against phytopathogenic bacteria. Moreover, the strain D747 treated at roots was able to reduce the leaf spot severity provoked by Psa in A. chinensis var. chinensis plants.