Surplus zinc ameliorates the response of tobacco plants to Xylella Fastidiosa infectios

Trabajo presentado en la XXIV Reunión de la Sociedad Española de Biología de Plantas y XVII Congreso Hispano-Luso de Biología de Plantas, celebrados en Vigo (online) del 7 al 9 de julio de 2021.Xylella fastidiosa, (Xf), is a xylem-confined bacteria and a quarantine pathogen organism in the EU that causes important diseases in vineyards and almond tree orchards in Mallorca (Balearic Islands) (Gomila et al., 2019). Zinc is a key micronutrient that participates in the plant’s protection against pathogens (Cabot et al., 2019). The virulence of Xf is affected, among other factors, by plant ionic composition. Zinc concentration has been related to planktonic growth and Xf biofilm production (Andersen et al., 2007; Navarrete et al., 2015). Here, the role of surplus Zn in the plant response to Xf has been studied in N. tabacum var. Petit Havana. Plants were grown in 50% Hoagland nutrient solution modified with 2 (control) or 12 μM (surplus Zn) Zn. In 2-month-old plants, the lowest non-senescent leaf in half of the plants for each Zn treatment were inoculated with Xf subp. fastidiosa. Forty days after inoculation, visual symptoms, plant biomass, and water content were recorded. Bacterial population in plant extracts was quantified by qPCR. Wilting symptoms were shown in the lower leaves of inoculated plants in both Zn treatments. Moreover, Xf accelerated flowering more markedly in control than in surplus Zn plants. In both Zn treatments, leaf fresh and dry biomass decreased in infected plants, with the exception of the youngest leaves in surplus Zn, which showed no differences with respect to control. Xf decreased water content in the leaves closest to the inoculation site, which showed the highest Xf colonization in both Zn treatments. Bacterial colonization decreased in the upper leaves, with surplus Zn plants showing the lowest values. Xf decreased total plant biomass in control plants, while no differences were found in the surplus Zn treatment. In surplus Zn, Xf-inoculated plants showed a significant increase in root growth with respect to control. Our results suggest that the ameliorating effect of surplus Zn in the response of tobacco plants to Xf could be related to promotion of the development of a larger root system, which could contribute to maintain plant growth, rather than surplus Zn having an inhibitory effect on bacterial colonization or improving leaf water status.This study is funded by the Regional Ministry of Agriculture, Fisheries and Food (Direcció General de Sanitat i Producció Agrària) of the Autonomous Government of the Balearic Islands and the Spanish Government (grant reference PID2019-104000-R).Peer reviewe

Descripción y caracterización de las variedades minoritarias tintas Esperó de gall y Callet negrella,y blancas Argamussa y Vinater blanc

[spa] La especie Vitis vinifera L. agrupa un número de variedades grande e impreciso. Hoy día, y a causa de razones económicas y administrativas básicamente (apego por la estandarización de los mercados hacia variedades señaladas, programas de reestructuración y transformación, etc.), su cultivo acostumbra a reunirse en un número concreto de ellas pudiendo significar esto una amenaza para la conservación del patrimonio genético vitícola. España es uno de los países cabecillas en el cultivo de la vid con un elevado número de variedades cultivadas. La región de las Baleares es una zona con una antigua y gran tradición vitivinícola. Sin embargo, y a pesar de su relevancia, el patrimonio vitícola balear ha residido parcialmente oculto a nivel oficial. De hecho, algunas variedades minoritarias, cuya excepcionalidad es contemplada a nivel local, siguen sin estar incorporadas en el registro de variedades comerciales (RVC). Teniendo en cuenta las limitaciones en el empleo de estas variedades y las exigencias del consumidor en cuanto a calidad y personalidad de los vinos, son precisas labores de caracterización de su potencial vitivinícola. Antes de incorporar estas variedades a los registros comerciales o de variedades recomendadas o autorizadas es necesario distinguirlas, catalogarlas y preservarlas. A continuación, se describen y caracterizan las variedades minoritarias tintas Esperó de gall y Callet negrella, así como las blancas Argamussa y Vinater blanc, con la finalidad de demostrar sus válidas aptitudes vitícolas y enológicas, además de evidenciar una conexión histórica como variedades autóctonas de las Islas Baleares, para su autorización en la misma región. Todas ellas muestran singularidades propias tales como la agudeza, el dulzor y la armonía de los vinos resultantes de las vinificaciones de la variedad Argamussa. Así como, por su parte, las aportaciones afrutadas de las variedades Esperó de gall y Vinater blanc y, la persistencia, estructura e intensidad en nariz y boca de la variedad Callet negrella.[eng] The species Vitis vinifera L. groups a large and imprecise number of varieties. Nowadays, and basically because of economic and administrative reasons (attachment for the standardization of the markets towards singular varieties, restructuring and transformation programs, etc.), their cultivation usually concentrated in an specific number of them, which can mean a threat to the conservation of the viticulture genetic resources. Spain is one of the leading countries in the cultivation of vines with a high number of cultivated varieties. The Balearic region is an area with an ancient and great winemaking tradition. However, and despite its relevance, the Balearic wine heritage has resided partially hidden at the official level. In fact, some minority varieties, whose exceptionality is contemplated at the local level, are still not included in the commercial variety register (CVR). Taking into account the limitations in the use of these varieties and the demands of the consumer in terms of quality and personality of the wines, precise work is required to characterize their winemaking potential. Before incorporating these varieties into commercial registers or of recommended or authorized varieties, it is necessary to distinguish, catalogue and preserve them. Below, the local red varieties Esperó de gall and Callet negrella are described and characterized, as well as the white Argamussa and Vinater blanc, with the aim of demonstrating their valid viticulture and oenological skills, as well as evidencing a historical connection as indigenous varieties of the Balearic Islands, to get their authorizations in the same region. All of them show their own peculiarities such as the sharpness, the sweetness and the harmony of the wines resulting from the winemaking of the Argamussa variety. As well as, on the other hand, the fruity contributions of the varieties Esperó de gall and Vinater blanc and the persistence, structure and intensity in the nose and mouth of the Callet negrella variety

Evaluation of Control Strategies for Xylella fastidiosa in the Balearic Islands

The emergence of Xylella fastidiosa (Xf) in the Balearic Islands in October 2016 was a major phytosanitary challenge with international implications. Immediately after its detection, eradication and containment measures included in Decision 2015/789 were implemented. Surveys intensified during 2017, which soon revealed that the pathogen was widely distributed on the islands and eradication measures were no longer feasible. In this review, we analyzed the control measures carried out by the Balearic Government in compliance with European legislation, as well as the implementation of its control action plan. At the same time, we contrasted them with the results of scientific research accumulated since 2017 on the epidemiological situation. The case of Xf in the Balearic Islands is paradigmatic since it concentrates on a small territory with one of the widest genetic diversities of Xf affecting crops and forest ecosystems. We also outline the difficulties of anticipating unexpected epidemiological situations in the legislation on harmful exotic organisms on which little biological information is available. Because Xf has become naturalized in the islands, coexistence alternatives based on scientific knowledge are proposed to reorient control strategies towards the main goal of minimizing damage to crops and the landscape

Camps d'aprenentatge de les Illes Balears

Se recoge la oferta de campos de aprendizaje de las Islas Baleares para el profesorado y alumnado de las Islas Baleares, a los que se ofrece la posibilidad de realizar estancias en un medio singular. Esta red está formada por los campos de aprendizaje de Son Ferriol, Es Palmer, sa Cala, es Pinaret y Orient.BalearesGovern de les Illes Balears. Secció de material didàctic i divulgació educativa; Passatge de Guillem de Torrella, 1, planta quarta; 07002 Palma de Mallorca, Illes Balears; 971 17 65 00; [email protected]

Phylogenetic inference enables reconstruction of a long-overlooked outbreak of almond leaf scorch disease (Xylella fastidiosa) in Europe

The recent introductions of the bacterium Xylella fastidiosa (Xf) into Europe are linked to the international plant trade. However, both how and when these entries occurred remains poorly understood. Here, we show how almond scorch leaf disease, which affects ~79% of almond trees in Majorca (Spain) and was previously attributed to fungal pathogens, was in fact triggered by the introduction of Xf around 1993 and subsequently spread to grapevines (Pierceʼs disease). We reconstructed the progression of almond leaf scorch disease by using broad phylogenetic evidence supported by epidemiological data. Bayesian phylogenetic inference predicted that both Xf subspecies found in Majorca, fastidiosa ST1 (95% highest posterior density, HPD: 1990–1997) and multiplex ST81 (95% HPD: 1991–1998), shared their most recent common ancestors with Californian Xf populations associated with almonds and grapevines. Consistent with this chronology, Xf-DNA infections were identified in tree rings dating to 1998. Our findings uncover a previously unknown scenario in Europe and reveal how Pierce’s disease reached the continent.This work was partially funded by projects XF-ACTORS (Xylella fastidiosa Active Containment Through a Multidisciplinary-Oriented Research Strategy; grant 727987 from European Union’s Horizon 2020 Framework Research Programme) and ERTA2017-00004-02 and E-RTA2017-00004-04 (Desarrollo de estrategias de erradicación, contención y control de X. fastidiosa en España) from ‘Programa Estatal de I + D + I Orientada a los Retos de la Sociedad of the Spanish Government’ and FEDER) and from the Organización Profesional del Aceite de Oliva Español’. M.P.V-A. was recipient of a PhD fellowship from Intramural Project 201840E111from CSIC. A.B. was recipient of a postdoctoral UIB contract funded by the Vicerectorado de Investigación e Internacionalización of the University of the Balearic Islands

Landscape Epidemiology of Xylella fastidiosa in the Balearic Islands

Xylella fastidiosa (Xf ) is a vascular plant pathogen native to the Americas. In 2013, it was first reported in Europe, implicated in a massive die-off of olive trees in Apulia, Italy. This finding prompted mandatory surveys across Europe, successively revealing that the bacterium was already established in some distant areas of the western Mediterranean. To date, the Balearic Islands (Spain) hold the major known genetic diversity of Xf in Europe. Since October 2016, four sequence types (ST) belonging to the subspecies fastidiosa (ST1), multiplex (ST7, ST81), and pauca (ST80) have been identified infecting 28 host species, including grapevines, almond, olive, and fig trees. ST1 causes Pierce’s disease (PD) and together with ST81 are responsible for almond leaf scorch disease (ALSD) in California, from where they were introduced into Mallorca in around 1993, very likely via infected almond scions brought for grafting. To date, almond leaf scorch disease affects over 81% of almond trees and Pierce’s disease is widespread in vineyards across Mallorca, although producing on average little economic impact. In this perspective, we present and analyze a large Xf -hosts database accumulated over four years of field surveys, laboratory sample analyses, and research to understand the underlying causes of Xf emergence and spread among crops and wild plants in the Balearic Islands. The impact of Xf on the landscape is discussed

Landscape Epidemiology of Xylella fastidiosa in the Balearic Islands

[eng] Xylella fastidiosa (Xf) is a vascular plant pathogen native to the Americas. In 2013, it was first reported in Europe, implicated in a massive die-off of olive trees in Apulia, Italy. This finding prompted mandatory surveys across Europe, successively revealing that the bacterium was already established in some distant areas of the western Mediterranean. To date, the Balearic Islands (Spain) hold the major known genetic diversity of Xf in Europe. Since October 2016, four sequence types (ST) belonging to the subspecies fastidiosa (ST1), multiplex (ST7, ST81), and pauca (ST80) have been identified infecting 28 host species, including grapevines, almond, olive, and fig trees. ST1 causes Pierce's disease (PD) and together with ST81 are responsible for almond leaf scorch disease (ALSD) in California, from where they were introduced into Mallorca in around 1993, very likely via in- fected almond scions brought for grafting. To date, almond leaf scorch disease affects over 81% of almond trees and Pierce's disease is widespread in vineyards across Mallorca, although producing on average little economic impact. In this perspective, we present and analyze a large Xf-hosts da- tabase accumulated over four years of field surveys, laboratory sample analyses, and research to understand the underlying causes of Xf emergence and spread among crops and wild plants in the Balearic Islands. The impact of Xf on the landscape is discussed