Diversity of Phytophthora Communities across Different Types of Mediterranean Vegetation in a Nature Reserve Area

Research Highlights: Protected natural areas are a reservoir ofPhytophthoraspecies and represent the most suitable sites to study their ecology, being less disturbed by human activities than other environments. Background and Objectives: The specific objective of this study was to correlate the diversity and distribution ofPhytophthoraspecies with the vegetation in aquatic, riparian and terrestrial habitats within a protected area in Eastern Sicily, Southern Italy. Materials and Methods: Environmental samples (water and soil) were sourced from two streams running through the reserve and six different types of vegetation, includingPlatano-Salicetum pedicellatae, theSarcopoterium spinosumcommunity,Myrto communis-Pistacietum lentisci,Pistacio-Quercetum ilicis,Oleo-Quercetum virgilianaeand a gallery forest dominated byNerium oleander(Natura 2000 classification of habitats).Phytophthoraspecies were recovered from samples using leaf baiting and were classified on the basis of morphological characteristics and sequencing of internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA). Results: As many as 11Phytophthoraspecies, within five different ITS clades, were identified, includingP. asparagi,P.bilorbang,P. cryptogea,P. gonapodyides,P. lacustris,P. multivora,P. nicotianae,P. oleae,P. parvispora,P. plurivoraandP. syringae. NoPhytophthoraspecies were found in theSarcopoterium spinosumcomm.Phytophthora asparagi, P. lacustrisandP. plurivorawere the prevalent species in the other five plant communities, but onlyP. plurivorawas present in all of them. Overall aquatic species from clade 6 (100 out of 228 isolates) were the most common; they were recovered from all five types of vegetation, streams and riparian habitats.Phytophthorapopulations found in thePlatano-Salicetum pedicellataeandOleo-Quercetum virgilianaeshow the highest diversity, while no correlation was found with the physicochemical characteristics of the soil.Conclusions:The vegetation type and the aquatic or terrestrial habitat were identified as major environmental factors correlated with the diversity ofPhytophthoracommunities in this reserve.