Summary This review comprises both well‐known and recently described Phytophthora species and concentrates on Phytophthora–woody plant interactions. First, comprehensive data on infection strategies are presented which were the basis for three models that explain invasion and spread of Phytophthora pathogens in different woody host plants. The first model describes infection of roots, the second concentrates on invasion of the trunk, and the last one summarizes infection and invasion of host plants via leaves. On the basis of morphological, physiological, biochemical and molecular data, scenarios are suggested which explain the sequences of reactions that occur in susceptible and tolerant plants following infections of roots or of stem bark. Particular emphasis is paid to the significance of Phytophthora elicitins for such host–pathogen interactions. The overall goal is to shed light on the sequences of pathogenesis to better understand how Phytophthora pathogens harm their host plants.

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Elicitins are a group of highly conserved proteins secreted by species of Phytophthora and a species of the related genus Pythium, Pythium vexans. Some of these proteins act as inducers of the necrotic hypersensitive-like response and the associated systemic acquired resistance phenomenon, in some species. We cloned and characterised the cinnamomin-beta and -alpha genes and two related elicitin genes from Phytophthora cinnamomi. These four open reading frames (ORFs) are clustered in tandem pairs. Two out of these four genes present homologies with the basic and acidic elicitin groups; but the two others encode, if expressed, elicitin isoforms exhibiting homologies with the class II of highly acidic elicitins.

Climate change is impacting locally adapted species such as the keystone tree species cork oak (Quercus suber L.). Quantifying the importance of environmental variables in explaining the species distribution can help build resilient populations in restoration projects and design forest management strategies. Using landscape genomics, we investigated the population structure and ecological adaptation of this tree species across the Mediterranean Basin. We applied genotyping by sequencing and derived 2,583 single nucleotide polymorphism markers genotyped from 81 individuals across 17 sites in the studied region. We implemented an approach based on the nearest neighbour haplotype ‘coancestry’ and uncovered a weak population structure along an east–west climatic gradient across the Mediterranean region. We identified genomic regions potentially involved in local adaptation and predicted differences in the genetic composition across the landscape under current and future climates. Variants associated with temperature and precipitation variables were detected, and we applied a nonlinear multivariate association method, gradient forest, to project these gene–environment relationships across space. The model allowed the identification of geographic areas within the western Mediterranean region most sensitive to climate change: south‐western Iberia and northern Morocco. Our findings provide a preliminary assessment towards a potential management strategy for the conservation of cork oak in the Mediterranean Basin.

The genetic variability of cork oak (Quercus suber, L.) in Portugal was evaluated by AFLP using five primer combinations. Three hundred and thirteen trees from three geographically contrasting regions exhibited a high level of genetic variation. The genetic profile of each individual is composed of 291 loci, randomly positioned in the genome and consists of monomorphic and polymorphic fragments. Similarities and dissimilarities among the individuals were quantitatively evaluated by numerical taxonomy. The overall sample shows a proportion of AFLP polymorphic markers of 71%, denoting a high level of variability. Ninety percent of the polymorphic markers identified in cork oak genotypes are uniformly distributed throughout the cork oak populations of Algarve, Alentejo and Trás-os-Montes regions. The coefficients of genetic similarity vary from 0.61 to 0.88 implying that 60% of fragments found are common. A sample of 52 holm oak [Quercus ilex subsp. rotundifolia (Lam.)] trees from overlapping areas was also analysed by AFLP with the same five primer combinations. However the codification of markers together with those selected on cork oak profiles was feasible with only one primer combination due to an apparent much higher polymorphism. AFLP and numerical taxonomy analysis enabled to differentiate the taxa and showed that the level of similarity observed between the profiles of the individuals from holm oak species was lower than that observed in cork oak, implying that apparently the degree of polymorphism is higher in Q. ilex subsp. rotundifolia than that quantified in Q. suber. A Bayesian approach was used to assess Q. suber total genetic diversity (Ht = 0.2534, P < 0.001) of which 1.7% (Fst = 0.0172, P < 0.001) was assigned to differences among populations. Analysis of molecular variance (AMOVA) showed that most genetic variation is comprised within populations (96%) while 3.6% is among populations (Φst = 0.036, P < 0.001). Differences among populations within geographic regions account for 2.6% (Φsc = 0.026, P < 0.001) of the total variation and only 1.3% (Φct = 0.013, P = 0.007) is attributed to variation among regions denoting little differentiation of populations over a range of 700 km.