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Several fungal species have been found associated with the Olive Quick Decline Syndrome (OQDS) caused by X. fastidiosa CoDiRO strain, among which some have long been recognized as primary pathogens of many plants (i.e. Phaeoacremonium and Pleurostomophora spp.), whereas other have not been described before. The new species Ps. oleae and Ps. oleicola, were associated with brown wood streaking of various olive varieties, both on young and centenarian trees. In order to ascertain the role of these fungi in the OQDS, pathogenicity tests were performed both in glasshouse, on young plants, and in the open field, on centenarian olive plants cv Cellina di Nardò. In glasshouse tests, fungal strains (Ph. aleophilum B1a, Ph. rubrigenum N20, Ps. oleae Fv84, Ps. oleicola M24, Pseudophaeomoniella sp. M51), were inoculated alone or in combination with X. fastidiosa CoDiRO strain. For the test in the field, naturally X. fastidiosa CoDiRO-infected and uninfected centenarian plants were inoculated with the same fungal strains. Results from the glasshouse tests, collected two years after the inoculation, indicate that fungal strain(s) alone are able to colonize the olive xylem, and to cause wood streaking. However, only few twigs showed wilting symptoms. Conversely, the combined inoculations with X. fastidiosa CoDiRO, induced extensive OQDS wilting symptoms. To date, results from the field observation 8 months after fungal inoculation show no differences in symptoms severity between X. fastidiosa infected and healthy plants. Aknowledgment This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N. 635646 “Pest Organisms Threatening Europe POnTE”. Bibliography Nigro F., Boscia D., Antelmi I. 6 Ippolito A. 2013. Fungal species associated with severe decline of olive in southern Italy. Journal of Plant Pathology, 95, 668. Martelli G. P., Boscia D., Porcelli F. & Saponari M. 2015. The olive quick decline syndrome in southeast Italy: a threatening phytosanitary emergency. European Journal of Plant Pathology (2015) DOI 10.1007/s10658-015-0784-7. Crous P.W., Wingfield M.J., Guarro J., Hernández-Restrepo M., Sutton D.A., Acharya K. & Barber P.A., et al. 2015. Fungal Planet description sheets: 320–370. Persoonia 34: 167–266. doi: 10.3767/003158515X688433 |
