Establishment of an experimental field to explore the differential olive cultivar response to Xylella fastidiosa infection

AuthorsM. Saponari, F. Palmisano, C. Dongiovanni, V. Cavalieri, G. Altamura, G. D’Attoma, G. Loconsole, M. Morelli, A. Saponari, D. Tavano, S. Zicca and D. Boscia

Type of contribution: Conference Abstract | Oral Presentation
Conference: 22th Congress of the Italian Society of Plant Pathology, 19-22 September 2016, Roma (Italy)
Keywords: Xylella, Field trials, Olive
Corresponding author: M. Saponari (CNR-IPSP)


While different sources of natural resistance to Xylella fastidiosa (Xf) have been described in grapevines and citrus, lack of consolidated information exists on the wide panel of cultivars characterizing the vast olive germplasm. Preliminary observations on few cultivars, support the evidence that differential cultivar responses to Xf infections may exist. To explore the response of a larger panel of cultivars, in April 2015, an experimental olive plot, located within the Xf-heavily affected olive groves, was established in the Apulia Region (Italy). Twenty-four trees for each of the ten different cultivars were planted in randomized blocks. Each tree was caged with 15-20 specimens of Philaenus spumarius collected from the neighboring infected olive groves. Upon removing the cages, the trees are then continuously exposed to the natural vector populations occurring in the area. Nine and 12-months after planting, the trees were sampled, tested for Xf and inspected for symptoms. The first data confirmed the infectivity of the vector populations occurring in the Apulian contaminated area and the Xf susceptibility of the olive cultivars tested. Almost 50% of the trees tested positive, with an infection incidence ranging from 25% (Leccino) to 78% (Koroneiki). Symptoms of shoot dieback started to appear 1-year after planting, limitedly on few replicates of Cellina di Nardò. In April 2016, the number of cultivars has been increased up to 30. Periodical surveys for symptoms and quantitative analyses to monitor the differential bacterial titer and expression of target genes involved in the host response, are underway.