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The occurrence of Grapevine fanleaf virus (GFLV) in 74 vineyards in grapevine-growing areas of Andalusia, southern Spain, was investigated, as well as the genetic variability of the coat protein (CP) gene on RNA2. Overall, the prevalence of GFLV (the percentage of vineyards with GFLV) was 24·3%, and it was most common in the Jerez-Xérès-Sherry and Manzanilla-Sanlúcar de Barrameda denomination of origin (DO) (29·4%) and Condado de Huelva DO (24·0%), followed by the Montilla-Moriles DO (13·3%). GFLV-infected plants showed fanleaf and yellow mosaic symptoms together with general vine decline. In almost all samples, except one from Jerez-Xérès-Sherry and Manzanilla-Sanlúcar de Barrameda DO and one from Condado de Huelva DO, GFLV-infected plants showed soil infestation by the virus vector nematode species Xiphinema index and/or the potential vector X. italiae. Reverse transcription-polymerase chain reaction (RT-PCR) successfully amplified the partial CP gene product of the expected size (555 bp) in leaves and nematode vectors. A total of 135 clones of the partial GFLV CP gene were analysed for sequence variation using single-strand conformation polymorphism, yielding 12 different haplotype patterns. Haplotypes were separated among the three different DO. The haplotype patterns MOB, MOC, MMA, MMC and HB were detected in leaf samples and nematode vectors for each locality, except for Jerez de la Frontera-429. Sequence analysis of the GFLV haplotypes revealed sequence variability within the haplotypes and greater abundance of some variants than others in the same sequenced haplotype pattern. Consequently, GFLV in southern Spain exists as a 'quasispecies', as it has been reported in other grapevine-growing areas of the world. This paper is the first report on the molecular variability of GFLV in Spain. [ABSTRACT FROM AUTHOR]

Morphologial, biochemical, molecular and karyological analyses of different populations and races of the stem and bulb nematode Ditylenchus dipsaci have suggested that it represents a species complex, of which only D. dipsaci sensu stricto and its morphologically larger variant, known as the giant race of the stem and bulb nematode, are plant parasites of economic importance. The present study singles out the giant race from this complex, herein described as a new species named Ditylenchus gigas n. sp., on the basis of morphological and molecular data obtained from several populations collected from broad beans in southern Italy, southern Spain and Lebanon. The new species epithet, which refers to the large body size of the nematode with respect to the normal races, must be considered to be conspecific with the D. dipsaci ‘giant race’ from Fabaceae in recent literature. Morphologically, the new species is characterized by a body size 1Æ5–2 times longer than the ‘normal race’, stylet delicate (11Æ5–13Æ0 lm long) with knobs distinctly sloping backwards, and long post-vulval uterine sac (81–150 lm long). Results of molecular analysis of rDNA sequences including the ITS1-5.8S-ITS2 region, the D2–D3 fragment of the 28S gene, the small 18S subunit, the partial mitochondrial gene for cytochrome c oxidase I (mtCOI), and hsp90 gene sequences, support the new taxonomic species status for the former D. dipsaci giant race from Vicia faba, and clearly distinguish D. gigas n. sp. from D. dipsaci sensu stricto. [ABSTRACT FROM AUTHOR]

High infection rates of European holly ( Ilex aquifolium) feeder roots by an unknown root-knot nematode were found in a holly forest at Arévalo de la Sierra (Soria province) in northern Spain. Holly trees infected by the root-knot nematode showed some decline and low growth. Infected feeder roots were distorted and showed numerous root galls of large (8–10 mm) to moderate (2–3 mm) size. Morphometry, esterase and malate dehydrogenase electrophoretic phenotypes and phylogenetic trees of sequences within the ribosomal DNA (rDNA) demonstrated that this nematode species differs clearly from other previously described root-knot nematodes. Studies of host-parasite relationships showed a typical susceptible reaction in naturally infected European holly plants, but did not reproduce on a number of cultivated plants, including tomato, grapevine, princess-tree and olive. The species is described here, illustrated and named as Meloidogyne silvestris n. sp. The new root-knot nematode can be morphologically distinguished from other Meloidogyne spp. by: (i) roundish perineal pattern, dorsal arch low, with fine, sinuous cuticle striae, lateral fields faintly visible; (ii) female excretory pore level with stylet knobs, or just anterior to them, EP/ST ratio about 0·8; (iii) second-stage juveniles with hemizonid located 1 to 2 annuli anterior to excretory pore and short, sub-digitate tail; and (iv) males with lateral fields composed of four incisures, with areolated outer bands. Phylogenetic trees derived from maximum parsimony analysis based on 18S, ITS1-5·8S-ITS2 and D2–D3 of 28S rDNA showed that M. silvestris n. sp. can be differentiated from all described root-knot nematode species, and it is clearly separated from other species with resemblance in morphology, such as M. ardenensis, M. dunensis and M. lusitanica. [ABSTRACT FROM AUTHOR]