Fungal biodiversity in freshwater, brackish and marine habitats was estimated based on reports in the literature. The taxonomic groups treated were those with species commonly found on submerged substrates in aquatic habitats: Ascomycetes (exclusive of yeasts), Basidiomycetes, Chytridiomycetes, and the non-fungal

Surveys (in 2002 and 2003) were performed for fungal endophytes in roots of 24 plant species growing at 12 sites (coastal and inland soils, both sandy soils and salt marshes) under either water or salt stress in the Alicante province (Southeast Spain). All plant species examined were colonized by endophytic fungi. A total of 1830 fungal isolates were obtained and identified by morphological and molecular [internal transcribed spacer (ITS) and translation elongation factor-1alpha gene region (TEF-1alpha) sequencing] techniques. One hundred and forty-two fungal species were identified, belonging to 57 genera. Sterile mycelia were assigned to 177 morphospecies. Fusarium and Phoma species were the most frequent genera, followed by Aspergillus, Alternaria and Acremonium. Fungal root endophytic communities were influenced by the soil type where their respective host plants grew, but not by location (coastal or inland sites). Fusarium oxysporum, Aspergillus fumigatus and Alternaria chlamydospora contributed most to the differences found between endophytic communities from sandy and saline soils. Host preference was found for three Fusarium species studied. Fusarium oxysporum and Fusarium solani were especially isolated from plants of the family Leguminosae, while Fusarium equiseti showed a preference for Lygeum spartum (Gramineae). In some cases, specificity could be related to intra-specific variability as shown by sequencing of the TEF-1alpha in the genus Fusarium.

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The plant trade is unwittingly accelerating the worldwide spread of well-known and new or undescribed Phytophthora species and creating novel niches for emerging pathogens. The results of a survey carried out from 2001 to 2006 in garden centres and nurseries of the Balearic Islands and eastern Spain combined with the analysis of samples received from ornamental nurseries from northern Spain reflected the extent of this global issue at the local scale. A total of 125 Phytophthora isolates were obtained from 37 different host species and 17 putative species identified on morphological features and direct sequencing of the internal transcribed spacer and four mitochondrial and nuclear genes. Five species, P. ramorum , P. hedraiandra , P . 'niederhauserii', P . 'kelmania' and P . 'taxon Pgchlamydo' were formally unknown to science prior to 2001. In addition, 37 new host/pathogen combinations were first records for Spain, highlighting the risk of non-coevolved organisms from different biogeographic origins coming into contact under managed environments. The problem generated by new or rare taxa of Phytophthora found in nurseries for which no prior information on natural habitat and ecology is available for pest risk analysis is discussed.

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Despite predicted global warming, the temperature effects on headwater stream functioning are poorly understood. We studied these effects on microbial-mediated leaf decomposition and the performance of associated aquatic hyphomycete assemblages. Alder leaves were incubated in three streams differing in winter water temperature. Simultaneously, in laboratory, leaf discs conditioned in these streams were incubated at 5, 10 and 15 °C. We determined mass loss, leaf N and sporulation rate and diversity of aquatic hyphomycete communities. In the field, decomposition rate correlated positively with temperature. Decomposition rate and leaf N presented a positive trend with dissolved nutrients, suggesting that temperature was not the only factor determining the process velocity. Under controlled conditions, it was confirmed that decomposition rate and leaf N were positively correlated with temperature, leaves from the coldest stream responding most clearly. Sporulation rate correlated positively with temperature after 9 days of incubation, but negatively after 18 and 27 days. Temperature rise affected negatively the sporulating fungi richness and diversity only in the material from the coldest stream. Our results suggest that temperature is an important factor determining leaf processing and aquatic hyphomycete assemblages and that composition and activity of fungal communities adapted to cold environments could be more affected by temperature rises. Highlight: Leaf decomposition rate and associated fungal communities respond to temperature shifts in headwater streams.

The capacity of Phytophthora ramorum to colonize the inner bark of 18 native and two exotic tree species from the Iberian Peninsula was tested. Living logs were wound-inoculated in a growth chamber with three isolates belonging to the EU1 and two to the NA1 clonal lineages of P. ramorum . Most of the Quercus species ranked as highly susceptible in experiments carried out in summer, with mean lesion areas over 100 cm 2 in Q. ). Pinus halepensis and P. pinea were highly susceptible, exhibiting long, narrow lesions; but three other pine species, P. pinaster , P. nigra and P. sylvestris , were resistant to slightly susceptible. No significant difference in aggressiveness was found between the isolates of P. ramorum . In addition, there was evidence of genetic variation in susceptibility within host populations, and of significant seasonal variation in host susceptibility in some Quercus species. The results suggest a high risk of some Iberian oaks to P. ramorum , especially in forest ecosystems in southwestern Spain, where relict populations of Q. canariensis grow amongst susceptible understory species such as Rhododendron ponticum and Viburnum tinus . One isolate of P. cinnamomi used as positive control in all the inoculations was also highly aggressive to Iberian oaks and Eucalyptus dalrympleana .

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