Xiphinema herakliensen. sp. from wild olive and cultivated trees in Vathy Rema and other localities, Heraklion province of Crete, Greece, is described based on morphological and molecular characters. The new species is characterised by having differentiation in the tubular part of the uterus, body length 4.1 (3.3-5.5) mm, odontostyle 149 (135-163) μm long, odontophore 85 (71-98) μm long, female tail dorsally convex-conoid with subdigitate peg, and presence of functional males. The polytomous identification code of the new species is: A4, B2 + 3, C5a, D6(5), E5, F4(5), G3, H2, I3, J5, K5, L2. The new species belongs to morphospeciesXiphinemanon-americanumGroup 5 characterised by having two equally developed female genital branches with uterine differentiation, presence of pseudo-Z-organ with small granular bodies plus small spines (in low number) and crystalloid bodies along uterus, and a short, rounded tail ending in a peg.Xiphinema herakliensen. sp. appears closely related toX. barense,X. horvatovicae,X. lanceolatum,X. loteni,X. sphaerocephalumandX. thorneanum, from which it may be differentiated morphologically and/or molecularly. The results of the phylogenetic analyses based on the sequences of the D2-D3 expansion regions of the 28S rRNA gene and ITS1 rRNA genes are also supportive of its specific status.

Summary: The present study is part of a survey for the identification of plant-parasitic nematodes in the rhizosphere of cultivated and wild olive trees in Crete, Greece. Sixteen species corresponding to 13 genera are added to 20 species belonging to 8 genera, previously reported in the survey. Seven nematode species, Filenchus ditissimus, Filenchus vulgaris, Ogma civellae, Pratylenchoides crenicauda, Psilenchus hilarulus, Tylenchus elegans, and Zygotylenchus guevarai, are recorded for the first time in Greece.

Defensins are small and rather ubiquitous cysteine-rich anti-microbial peptides. These proteins may act against pathogenic microorganisms either directly (by binding and disrupting membranes) or indirectly (as signaling molecules that participate in the organization of the cellular defense). Even though defensins are widespread across eukaryotes, still, extensive nucleotide and amino acid dissimilarities hamper the elucidation of their response to stimuli and mode of function. In the current study, we screened the Solanum lycopersicum genome for the identification of defensin genes, predicted the relating protein structures, and further studied their transcriptional responses to biotic (Verticillium dahliae, Meloidogyne javanica, Cucumber Mosaic Virus, and Potato Virus Y infections) and abiotic (cold stress) stimuli. Tomato defensin sequences were classified into two groups (C8 and C12). Our data indicate that the transcription of defensin coding genes primarily depends on the specific pathogen recognition patterns of V. dahliae and M. javanica. The immunodetection of plant defensin 1 protein was achieved only in the roots of plants inoculated with V. dahliae. In contrast, the almost null effects of viral infections and cold stress, and the failure to substantially induce the gene transcription suggest that these factors are probably not primarily targeted by the tomato defensin network.