xf-actors | icerya

Projects on Xylella fastidiosa and its insect vectors (2016 - 2021)

This project aims to answer the urgent need to improve prevention, early detection and control of the bacteria Xylella fastidiosa (Xf) in Europe through a multidisciplinary approach. Recently, Xf was introduced to Italy, where it is causing severe damage to olive crops, and to France, where it is so far limited to ornamental plants and some landscape trees. The overall goal of the research program is to assess the potential of Xf to spread throughout the EU territory, through a multifactor / multidisciplinary approach, based on a seamless integration amongst the 29 partners involved. Proposed actions are complementary to those carried out under the Project POnTE - 635646, thus ensuring an unbroken continuity with currently ongoing efforts. Specific objectives have been outlined following a step-by-step route, from preventing the introduction of Xf to free areas to the establishment of successful eradication strategies in infected zones. Preventive measures against Xf will be strengthened by implementing EU certification programs and developing a plan for establishing a EU Clean Plant Network. EU policy makers will be supported through the development of pest risk assessment tools, focused on current outbreaks and forecasting potentially threatened regions. Surveillance will be properly implemented, supporting the development of early detection tools for field use, remote sensing technology and predictive modelling. Critical information on the pathogen biology, epidemiological traits and hosts under threat, will be gathered with the guidance of an American research groups with long-established research (Almeida lab). At the same time, the insect-bacteria interactions will be determined, for developing strategic control measures. The final overall objective is a comprehensive integrated management strategy for diseases associated with Xf, applicable to both IPM and organic farming systems, to prevent Xf spread, control its economic, environmental/social impact, when an outbreak would occur.

Leader : Maria Saponari (IPSP, CNR, Italy).

Partners : see the dedicated website : http://www.xfactorsproject.eu/

Project founded by The EU Framework Program for Research and Innovation

more about the project

Our contribution to the project : We will contribute to the global database for the molecular identification of insect vectors of Xf and we also propose to decipher the network of feeding and hosting relationships between vectors, plant hosts and Xf using Next Generation Sequencing (NGS) methods. Indeed, thanks to NGS methods it is possible to sequence a dozen of genetic markers on a thousand of samples while keeping sufficient sequencing depth to obtain reliable sequences. We will work on an integrated tool to infer networks of interaction in French contaminated areas to enable i) the identification of the potential vectors (via COI sequencing and comparison to the barcode database), ii) the identification of the last species of plants the vector fed on (via sequencing of RbCl + MatK) as well as iii) the identification of the strain of Xf the vector may host (via sequencing of the 7 loci included in the MLST scheme of Xf). By allowing the multiplexing of a thousand specimens (or pool of specimens) at a time, this tool may lead to quantitative data and consequently quantitative network of relationships. Once completely adapted such a tool could help to better understand the exchanges within and between plant - vector communities in space and time around the infested crops. It offers the possibility to address further questions on the dynamics of the epidemy as well as on the involved actors (spontaneous vegetation, asymptomatic plants and vector communities)

XF-ACTORS (2017 - 2021)

Xylella Fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy

We are involved in several research projects that deal with the bacterium Xylella fastidiosa (Xf) and its insect vectors. Our main objectives are :

i) to better understand the parameters that drive the spread of Xf (dispersion, climat, landscape, vector occurences).

ii) build up a reference database for the identification of european vectors of Xf that will contain information regarding their taxonomy, biology as well as images and a short sequence of DNA (barcode) for ca 10 specimens per species in different geographic areas. The database will be web-interfaced and users could compare a query DNA sequence to our reference database to get an identification (see examples of databases we already developped)

iii) develop highthrouput methods for the identification of the strain of Xf insects may carry. The idea here is to be able to rapidely screen populations of insects to assess the spread of Xf in the environment

iv) decipher the network of feeding and hosting relationships between vectors, plants and Xf using Next Generation Sequencing (NGS) methods. Indeed, thanks to NGS methods it is possible to sequence a dozen of genetic markers on a thousand of insect samples (one to identify the insect, a few others to identify the last plant they fed on and the strain of Xf). The idea is to better understand the exchanges within and between plant - vector communities in space and time around the infested crops. We could then better understand the dynamics of the epidemy as well as who are the involved actors (spontaneous vegetation, asymptomatic plants and vector communities) and what is their respective role.

People involved : A. Cruaud, J.-Y. Rasplus, J.-P. Rossi, J.-C Streito, G. Genson, S. Nidelet, E. Pierre, J.-M. Thuillier, M. Chartois, M. Godefroid, A.-A. Gonzalez

Below a few more details on the projects. Some have a much larger scope that our own objectives listed above :

Eco-epidemiology of Xylella fastidiosa in Corsica

In this project we will analyse the interactions between plants and insect vectors of Xf in Corsica. The goal is to produce knowledge about the ecology and biology of the insects (host plant, abundancy, phenology etc.) and potentail features that may influence the tranmission of Xf to plants. This should help to implement better strategies to limit the spread of the disease (e.g. through agroecology) and predict what are the areas that may be impacted in the next future (e.g because of climate change).

More specifically this project aims to : i) assess vector ability to transmit the disease to plants (indeed an insect may carry Xf but be unable to transmit it) ii) study the biology and ecology of species identified as efficient vectors (i.e. Philaenus spumarius) or that are supposed to be efficient, iii) study the network of interactions between Xf / plants / insects and what are the consequences on the spread of the disease. The expected output is to propose methods that may be implemented in Corsica to limit the spread of the disease. During the course of the project we will implement a reference database for the identification of corsican plants and vectors that we will use to decipher the network of interaction. The database will contain information regarding the taxonomy, biology/ecology of plants / insects as well as images and a short sequence of DNA (barcode) that will allow to identify them. The database will be web-interfaced and users could compare a query DNA sequence to our reference database to get an identification.

Leaders : F. Casabianca (INRA) & J.-Y. Rasplus

Partners : L. Hugot CNBC, M. Gibernau Univ. Corse

projet corse

projet Xfactors

Increasing knowledge on Xylella fastidiosa and its

insect vectors to monitor epidemics and better battle its spread

In this project we have three mains objectives :

1) Identify the host range of the different strains of Xf detected in France. This task is managed by M.-A. Jacques (INRA IRHS)

2) Develop high-throughput methods for the simultaneous identification of insect vectors and the strain of Xf they may carry. The idea here is to be able to rapidely screen populations of insects to assess the spread of Xf in the environment. This work will be conducted in collaboration with S. Santoni (INRA AGAP)

3) Provide a first risk assessment through modelling : i.e. try to understand the parameters that drive the spread of Xf (dispersion, climat, landscape, vector occurences, etc.). This work will be conducted in collaboration with S. Soubeyrand (INRA, BIOSP)

Ultimately, our goal is to improve our toolbox to prevent the introduction of phytopathogens transmitted by insects, monitor epidemics and better battle their spread. Thus, the tools developped during the project will be transferred to the french ministry of agriculture and the French Agency for Food, Environmental and Occupational Health & Safety (ANSES)

Leaders : J. Auricoste (DGAL), C. Lannou (INRA)

Harmonized protocol for monitoring and detection

of Xylella fastidiosa in its host plants and its vectors

The project has the objective to produce rapid and reliable detection protocols for monitoring Xf in different species of plants and vectors, with emphasis on improving sampling techniques, protocols for processing of samples (i.e., DNA extraction), and methods for isolating X. fastidiosa in culturing medium to fulfil quarantine and monitoring requirements. The key outputs should be i) a common protocol for sampling and processing of plant/bacteria extract, with special emphasis on isolation of viable cells of X. fastidiosa. ii) Harmonized and validated detection methods to determine the prevalence of Xf in plants and insects.