Abstract
The Mediterranean basin is recognized as a global biodiversity hotspot accounting for more than 25,000 plant species that represent almost 10% of the world’s vascular flora. In particular, the maquis vegetation on Mediterranean islands and archipelagos constitutes an important resource of the Mediterranean plant diversity due to its high rate of endemism. Since 2009, a severe and widespread dieback and mortality of Quercus ilex trees and several other plant species of the Mediterranean maquis has been observed in the National Park of La Maddalena archipelago (northeast Sardinia, Italy). Infected plants showed severe decline symptoms and a significant reduction of natural regeneration. First studies revealed the involvement of the highly invasive wide-host range pathogen Phytophthora cinnamomi and several fungal pathogens. Subsequent detailed research led to a better understanding of these epidemics showing that multiple Phytophthora spp. were involved, some of them unknown to science. In total, nine Phytophthora species were isolated from rhizosphere soil samples collected from around symptomatic trees and shrubs including Asparagus albus, Cistus sp., Juniperus phoenicea, J. oxycedrus, Pistacia lentiscus and Rhamnus alaternus. Based on morphological characters, growth-temperature relations and sequence analysis of the ITS and cox1 gene regions, the isolates were identified as Phytophthora asparagi, P. bilorbang, P. cinnamomi, P. cryptogea, P. gonapodyides, P. melonis, P. syringae and two new Clade 6 taxa which are here described as P. crassamura sp. nov. and P. ornamentata sp. nov. Pathogenicity tests supported their possible involvement in the severe decline that is currently threatening the Mediterranean maquis vegetation in the La Maddalena archipelago.
Highlights
The Mediterranean basin has been recognised as one of the world’s 25 biodiversity hotspots for priority conservation, accounting for more than 25,000 plant species, around half of which are endemic [1]
Growth-temperature relations and sequence analysis of the ITS and cox1 gene regions, the isolates were identified as Phytophthora asparagi, P. bilorbang, P. cinnamomi, P. cryptogea, P. gonapodyides, P. melonis, P. syringae and two new Clade 6 taxa which are here described as P. crassamura sp. nov. and P. ornamentata sp. nov
Dieback and mortality of plant species typical of the Mediterranean maquis were common along slopes downhill of roads and trekking paths in all the three investigated sites within the National Park of La Maddalena archipelago (Fig 1)
Summary
The Mediterranean basin has been recognised as one of the world’s 25 biodiversity hotspots for priority conservation, accounting for more than 25,000 plant species, around half of which are endemic [1]. The Tyrrhenian islands and archipelagos are characterized by an extremely high degree of endemism [2] This characteristic is mainly the outcome of the geological and climatic history during the Cenozoic era, when these territories became a crossroad of taxa from different continents and served as floristic refuges during interglacial periods [3]. The National Park of La Maddalena archipelago (Italy), located between northeast Sardinia and southern Corsica, is considered a micro-hotspot, hosting more than one thousand vascular-plant taxa, 54 being Sardinian endemics [4]. This archipelago comprises 7 major islands and 55 small islets, covering a land area of around 5,134 hectares [5]. Because of its unique habitats, the archipelago of La Maddalena has been declared as a Site of Community Importance and Special Protection Area for biodiversity conservation (Council Directive 92/43/EEC)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
