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Results Paragraph: Ribosomal sequence characterization. Fig. 1: This figure is missing and the legend of Fig. 1 is erroneously labeled as Fig. 2, and associated to the phylogenetic tree which corresponds to Fig. 2.

The spiral nematode Helicotylenchus oleae is an ectoparasite of olive roots and is distributed in some countries in the Mediterranean Basin. In this study, we provided morphological and molecular characterisation of topotypes from southern Italy, as well as of several other populations from Crete (Greece) and Spain. Correct identification of plant-parasitic nematode species is essential to establish appropriate control strategies and for preventing their spread to other areas. Helicotylenchus oleae is reported for the first time in Greece (Crete). Integrative morphometric and molecular data for H. oleae populations using D2-D3 expansion segments of 28S rDNA, ITS-rDNA, and the cytochrome c oxidase subunit 1 (coxI), were in agreement with the original descriptions of the species, except for some minor differences, which may be a result of intraspecific variability. The phylogenetic relationships of this species with other representatives of Helicotylenchus spp. using D2-D3 expansion segments and the ITS-rRNA region was studied showing a low intraspecific diversity for H. oleae species. For the first time, coxI molecular data is obtained for the genus Helicotylenchus., This research was supported by grant P12-AGR 1486 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, ‘Una manera de hacer Europa’, grant 201740E042, "Análisis de diversidad molecular, barcoding, y relaciones filogenéticas de nematodos fitoparásitos en cultivos mediterráneos" from Spanish National Research Council (CSIC), grant KBBE 219262 ArimNET-ERANET FP7 2012-2015 Project PESTOLIVE ‘Contribution of olive history for the management of soilborne parasites in the Mediterranean basin’ from Hellenic Agricultural Organization-DEMETER and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and AGL-2012-37521 from ‘Ministerio de Economía y Competitividad’ of Spain.

The reniform nematodes of the genus Rotylenchulus are semi-endoparasites of numerous herbaceous and woody plant roots and distributed in regions with Mediterranean, subtropical and tropical climates. In this study, we provide morphological and molecular characterisation of three out of 11 valid species of the genus Rotylenchulus: R. macrodoratus, R. macrosoma, and R. reniformis from Greece (Crete), Italy and Spain. The overall prevalence of reniform nematodes in wild and cultivated olives in Greece, Italy, and Spain was 11.5%, 19.0% and 0.6%, respectively. In Greece, R. macrodoratus and R. macrosoma were detected in cultivated olive with a prevalence of 8.2% and 6.2%, respectively, but none of them were found in wild olive. This is the first report of R. macrosoma in Greece. Only one reniform nematode species was detected in olive from Italy and Spain, viz. R. macrodoratus and R. macrosoma, respectively. The parasitism of R. macrosoma on hazelnut in northern Spain was also confirmed for the first time. This study demonstrates that R. macrodoratus and R. macrosoma have two distinct rRNA gene types in their genomes, specifically the two types of D2-D3 for R. macrosoma and R. macrodoratus, the two types of ITS for R. macrodoratus and the testing of the ITS variability in other R. macrosoma populations in different countries. Rotylenchulus macrosoma from Greece and Spain showed differences in nucleotide sequences in the ITS region and D2-D3 of 28S rRNA gene., This research was supported by grant P12-AGR 1486 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, ‘Una manera de hacer Europa’, grant KBBE 219262 ArimNET-ERANET FP7 2012-2015 Project PESTOLIVE ‘Contribution of olive history for the management of soilborne parasites in the Mediterranean basin’ from Hellenic Agricultural Organization-DEMETER and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and AGL-2012-37521 from ‘Ministerio de Economía y Competitividad’ of Spain. I. G. Birmpilis was employed by the ARIMNET-PESTOLIVE project.

During a survey, in the Perthshire hills, Scotland, altitude 800-900 m a.s.l., samples of Dryas octopetala leaves showing concomitantly symptoms of galls and discolored spots, were collected. Several nematodes, juveniles and adults, were isolated by dissecting foliar tissues. Two species of nematodes, recovered and identified at morphological and molecular level as Aphelenchoides sp. and Subanguina radicicola, are herein reported. The most significant diagnostic characters for species identification of nematode specimens extracted from Dryas leaf galls fitted well with those previously reported for S. radicicola. Concerning the Aphelenchoides sp., the diagnostic characters were very similar to those reported for A. ritzemabosi.The ITS and the D2-D3 expansion domain analyses confirmed the presence of S. radicicola from galls, while Aphelenchoides specimens from discoloured leaf areas), despite the morphological similarity with A. ritzemabosi, were genetically distinct from A. ritzemabosi based on two genomic regions (LSU and ITS). The 18S rRNA gene (SSU) was only amplified in S. radicicola. Phylogenetic analyses using ITS and LSU sequences placed S. radicicola with other populations of the same species and Aphelenchoides sp. with species of the same genus. The histopathology, caused by both endoparasites in naturally infected leaves, was examined via serial sections mounted on glass slides. Green Dryas leaves infected by Aphelenchoides sp. appeared discolored (yellowish spots), slightly deformed with a population density of four specimens/cm(2) per single leaf blade. Dryas octopetala leaves infected by S. radicicola showed an average of three galls/leaf, located randomly, mainly at the upper leaf edge. Dissected galls contained a central cavity with a variable number of adult females (3-6)/gall and males, together with several immature females, juvenile stages and eggs. The present study reports on a new host plant and an undescribed type of sedentary parasitism of the root-gall nematode, S. radicicola on D. octopetala leaves with the concomitant infection of specimens of Aphelenchoides sp.

This research carried out an accurate identification of the root-knot and cyst-forming nematode species parasitizing white clover at the Laceno Lake area in Southern Italy. Two species, the root-knot nematode Meloidogyne hapla and the cyst nematode Heterodera daverti were identified by integrative taxonomic approaches (classical, isozyme pattern, and D2-D3 expansion segments of 28S rRNA, ITS rRNA and coxI of mtDNA gene sequences) and found parasitizing white clover roots. These nematodes were detected in stunted plants with a reduced number of rhizobium nodules and the host suitability was confirmed by the high nematode population densities ranging from 53 to 2350 eggs and J2s per g of fresh roots for M. hapla, and 1.36 eggs and J2s/cm3 of soil for H. daverti; and cyst nematode females were also detected on the roots of clover. The studies on the host-parasite relationships of nematode-feeding sites in white clover roots infected by these nematodes showed a high susceptible response. Meloidogyne hapla and H. daverti infections were also observed on nitrogen-fixing root nodules of white clover, where well established feeding sites allowed active nematode reproduction. Histological examination of nitrogen-fixing root nodule tissues revealed that the nematodes established their permanent feeding sites in the vascular bundles of nodules which appeared enlarged deformed and disorganised by the expansion of nematode feeding cells (giant cells and syncytium) and hyperplasia of the nodule cortex. Additionally, coxI of mtDNA gene is an efficient barcoding sequence for discriminating the identification of H. daverti from H. trifolii., The present work has been done in the frame of the Apulia Region Programme: Misura 214/4 sub azione a “Progetti integrati per la Biodiversità” PSR 2007–2013, ASSE II “Miglioramento dell’ ambiente e dello Spazio Rurale” SaVeGraINPuglia.

14 pages, 13 figures., Chickpea (Cicer arietinum) is a cool-season food legume second in importance as a pulse crop in the world after beans (Phaseolus vulgaris). It is an important protein source in many regions of the semi-arid tropics. Chickpea is grown in 47 countries and is a significant component of subsistence cropping systems for farmers in the Indian Subcontinent, West Asia, the Mediterranean Basin, and certain areas of East and North Africa. More than 90% of the chickpea crops are grown in eight countries, including India, Pakistan, Iran, Turkey, Ethiopia, Mexico, Australia and Canada, in decreasing order., Many species of plant-parasitic nematodes have been reported in the roots and rhizosphere of chickpea in the major growing regions in the world (Table 1). However, only certain nematode species are considered constraints to chickpea production, causing an estimated 14% in annual yield losses (61,68). The symptoms and signs of nematode parasitism on chickpea differ depending upon the nematode’s feeding habit. Moreover, nematode attacks can make plants more sensitive to other biotic and abiotic stresses, and overall result in stunting and poor yield., Original results from the authors reported in this article were derived from research supported by grants (AGL2003-0640, AGL2004-01231) from Dirección General de Investigación, Ministerio de Educación y Ciencia, Spain.

Meloidogyne megadora infects coffee trees, an economically important crop worldwide. The accurate identification of M. megadora is essential for the development of preventive measures to avoid the dispersion of this pathogen and establishment of efficient and sustainable integrated pest management programs. One M. megadora isolate was studied by biometrical, biochemical, and molecular characteristics (random amplified polymorphic DNA [RAPD] and PCR of internal transcribed spacer [ITS] region). Biometrical characteristics of M. megadora females, males, and second-stage juveniles were similar to the original description. Biochemical studies revealed a unique enzyme pattern for M. megadora esterases (Me3) that allowed for species differentiation. Three RAPD primers (OPG-4, OPG-5, and OPG-6) produced specific bands to all Meloidogyne spp. studied: M. megadora, M. arenaria, M. incognita, and M. javanica. Molecular analysis of the ITS region resulted in an amplification product of 700 bp. The phylogenetic relationship between M. megadora and several Meloidogyne spp. sequences was analyzed, revealing that M. megadora clearly differs from the most common root-knot nematode species. Based on the studies conducted, isozyme analysis remains a useful and efficient methodology for M. megadora identification when females are available. Further studies will be needed to convert the M. megadora differential DNA fragment obtained by RAPD and develop a species-specific sequence-characterized amplified region PCR assay for its diagnosis based on second-stage juveniles.

A new longidorid nematode, Longidorus asiaticus n. sp., is described and illustrated from a population extracted from soil associated with the movement of crape myrtle (Lagerstroemia indica) flowering bonsai trees imported from China into Italy. The new needle nematode is characterised by a small body size (2.74–3.52 mm), a bluntly-rounded lip region, ca 12 μm wide, continuous with body contour, amphidial fovea pocket-shape with posterior end rounded not bilobed, a moderately long and flexible odontostyle ca 85 μm long, stylet guiding ring located at ca 37 μm from anterior end, vulva almost equatorial (48–54 %), tail short, about 2/3 of its width, dorsally convex-conoid, with rounded terminus, with a c’ ratio ca 0.7, bearing two pairs of caudal pores and male absent. Integrative diagnosis was completed with molecular data obtained using D2-D3 expansion segments of 28S rDNA, ITS-rDNA, and partial 18S-rDNA. The phylogenetic relationships of this species with other Longidorus spp. using D2-D3 expansion segments, ITS and partial 18S-rDNA indicated that L. asiaticus n. sp. clustered together with L. hangzhouensis, Longidorus sp. JH-2014, and L. camelliae: all of them sharing a common Asiatic geographic origin., This research was partially supported by grant AGR-136 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, “Una manera de hacer Europa”.

Cyst nematodes obtained from commercial carrot fields in Ontario (Canada) and northern and southern Italy were subjected to morphological and molecular examination. Morphology of cyst cone tops, males and second-stage juveniles (J2) indicated the nematode species was the Carrot Cyst Nematode (CaCN), Heterodera carotae. The sequence of the Internal Transcribed Spacer (ITS), D2-D3 region of the 28S gene of ribosomal RNA, cytochrome oxidase I of mitochondrial DNA (coxI), and a heat shock protein gene (hsp90), from single cysts were also examined. Sequences of ITS and D2-D3 placed all the nematodes with Heterodera carotae and other Heterodera spp. belonging to the Goettingiana group in the same clade. The novel nine coxI sequences obtained also clustered in a well-supported phylogenetic clade for H. carotae. Similarly, the six new hsp90 sequences of H. carotae generated in this study were placed in a well-supported clade (PP = 1.00) together with other two sequences of H. carotae from Greece. Restriction Fragment Length Polymorphism (RFLP) of ITS-PCR products gave a restriction pattern for RsaI different than H. carotae but the other 6 restriction patterns were similar as described in former research. A diagnostic conventional PCR method was developed based on a primer set to be specific for H. carotae using coxI sequence. These primers were also used in real time PCR to generate a melt curve specific to H. carotae. Limit of detection for CaCN in conventional PCR reaction was a single J2., This research was supported by grant AGR-136 “Consejería de Economía, Innvovación y Ciencia” from Junta de Andalucía and “Una manera de hacer Europa” from Unión Europea, Fondo Europeo de Desarrollo regional, and the Canada Research Chair Program to M. Tenuta. Juan E. Palomares-Rius was a recipient of a “Juan de La Cierva” contract from Ministerio de Economía y Competitividad of Spain.

Plant-parasitic nematodes (PPNs) interact with plants in different ways, for example, through subtle feeding behavior, migrating destructively through infected tissues, or acting as virus-vectors for nepoviruses. They are all obligate biotrophic parasites as they derive their nutrients from living cells which they modify using pharyngeal gland secretions prior to food ingestion. Some of them can also shield themselves against plant defenses to sustain a relatively long lasting interaction while feeding. This paper is centered on cell types or organs that are newly induced in plants during PPN parasitism, including recent approaches to their study based on molecular biology combined with cell biology-histopathology. This issue has already been reviewed extensively for major PPNs (i.e., root-knot or cyst nematodes), but not for other genera (viz. Nacobbus aberrans, Rotylenchulus spp.). PPNs have evolved with plants and this co-evolution process has allowed the induction of new types of plant cells necessary for their parasitism. There are four basic types of feeding cells: (i) non-hypertrophied nurse cells; (ii) single giant cells; (iii) syncytia; and (iv) coenocytes. Variations in the structure of these cells within each group are also present between some genera depending on the nematode species viz. Meloidogyne or Rotylenchulus. This variability of feeding sites may be related in some way to PPN life style (migratory ectoparasites, sedentary ectoparasites, migratory ecto-endoparasites, migratory endoparasites, or sedentary endoparasites). Apart from their co-evolution with plants, the response of plant cells and roots are closely related to feeding behavior, the anatomy of the nematode (mainly stylet size, which could reach different types of cells in the plant), and the secretory fluids produced in the pharyngeal glands. These secretory fluids are injected through the stylet into perforated cells where they modify plant cytoplasm prior to food removal. Some species do not produce specialized feeding sites (viz. Ditylenchus, Subanguina), but may develop a specialized modification of the root system (e.g., unspecialized root galls or a profusion of roots). This review introduces new data on cell types and plant organs stimulated by PPNs using sources varying from traditional histopathology to new holistic methodologies., This research was supported by grant P12-AGR 1486 from “Consejeria de Economia, Innvovacion y Ciencia” from Junta de Andalucia, and Union Europea, Fondo Europeo de Desarrollo regional, “Una manera de hacer Europa”; grants AGL2016-75287-R, PCIN-2013-053 by the Spanish Government and grant PEII-2014-020-P by the Castilla-La Mancha Government. JC is supported by a Cytema-Santander contract from UCLM.

A survey was conducted in 16 fields cultivated with broad bean (Vicia faba L.) and garden pea (Pisum sativum L.) in nine localities of Apulia, southern Italy, to determine whether annual weeds were susceptible to the pea cyst nematode (PEACN), Heterodera goettingiana, and could therefore serve as alternate host for the nematode. The results of this study showed that black medick (Medicago lupulina L.) is a good host for the nematode increasing its population levels in the soil in the absence of the primary hosts. The identity of the PEACN was confirmed by integrative taxonomic approaches (classical, and molecular), resulting identical in all cases (broad bean and garden pea, as well as the spontaneous black medick infections). The phylogenetic analyses using ITS and coxI gene regions strongly support the identification of the populations of H. goettingiana from Italy. Also, ITS and coxI gene sequences were obtained from the same cyst, confirming the species identity in comparison to other nematodes and populations in the Goettingiana group, demonstrating that ITS and coxI gene regions of the PEACN are suitable molecular markers for accurate and unequivocal identification of the PEACN. Reproduction and histopathological analyses demonstrated a good host-suitability of black medick to the PEACN. This record enlarges the relatively narrow host-range of the pea cyst nematode and indicates the need to control M. lupulina to avoid the increase of the nematode population in the absence of the main host crop., The present work has been done in the frame of the Apulia Region Programme: Misura 214/4 sub azione a “Progetti integrati per la Biodiversità” PSR 2007-2013, ASSE II “Miglioramento dell’ ambiente e dello Spazio Rurale” SaVeGraINPuglia. The authors are thankful to Dr. Nicola Vovlas IPSP- CNR, Bari U. O. S. for suggestions and fruitful comments on the manuscript, and C. Cantalapiedra-Navarrete (IAS-CSIC) for the excellent technical assistance.

Summary The potato cyst nematodes (PCNs) Globodera pallida and Globodera rostochiensis are important parasites of potato. PCNs undergo complex biotrophic interactions with their hosts that involve gene expression changes in both the nematode and the host plant. The aim of this study was to determine key genes that are differentially expressed in Globodera pallida life cycle stages and during the initiation of the feeding site in susceptible and partially resistant potato genotypes. For this purpose, two microarray experiments were designed: (i) a comparison of eggs, infective second-stage juveniles (J2s) and sedentary parasitic-stage J2s (SJ2); (ii) a comparison of SJ2s at 8 days after inoculation (DAI) in the susceptible cultivar (Desiree) and two partially resistant lines. The results showed differential expression of G. pallida genes during the stages studied, including previously characterized effectors. In addition, a large number of genes changed their expression between SJ2s in the susceptible cultivar and those infecting partially resistant lines; the number of genes with modified expression was lower when the two partially resistant lines were compared. Moreover, a histopathological study was performed at several time points (7, 14 and 30 DAI) and showed the similarities between both partially resistant lines with a delay and degeneration in the formation of the syncytia in comparison with the susceptible cultivar. Females at 30 DAI in partially resistant lines showed a delay in their development in comparison with those in the susceptible cultivar.

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 1AE5‐2 times longer than the ‘normal race’, stylet delicate (11AE5‐13AE0 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.

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.

Host–parasite relationships and pathogenicity of Meloidogyne javanica on potatoes (newly recorded from Malta) were studied under glasshouse and natural conditions. Potato cvs Cara and Spunta showed a typical susceptible reaction to M. javanica under natural and artificial infections, respectively. In potato tubers, M. javanica induced feeding sites that consisted of three to four hypertrophied giant cells per adult female. Infection of feeder roots by the nematode resulted in mature large galls which usually contained at least one mature female and egg mass. In both tubers and roots, feeding sites were characterized by giant cells containing granular cytoplasm and many hypertrophied nuclei. Cytoplasm in giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density ( P ) [0–64 eggs + second-stage juveniles (J2s) per cm 3 soil] and growth of cv. Spunta potato seedlings was tested under glasshouse conditions. A Seinhorst model [ y = m + (1 − m ) z ( P − T ) ] was fitted to fresh shoot weight and shoot height data of nematode-inoculated and control plants. Tolerance limits ( T ) for fresh shoot weight and shoot height of cv. Spunta plants infected with M. javanica were 0·50 and 0·64 eggs + J2s per cm 3 soil, respectively. The m parameter in that model (i.e. the minimum possible y -values) for fresh shoot weight and shoot height were 0·60 and 0·20, respectively, at P = 64 eggs + J2s per cm 3 soil. Root galling was proportional to the initial nematode population density. Maximum nematode reproduction rate was 51·2 at a moderate initial population density ( P = 4 eggs + J2s per cm 3 soil)., peer-reviewed

Host–parasite relationships in root-knot disease of spinach caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Nematode-induced mature galls were large and usually contained one or more females and egg masses with eggs. Feeding sites were characterized by the development of giant cells containing granular cytoplasm and many hypertrophied nuclei. The cytoplasm in these giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density (Pi) in a series from 0–128 eggs and second-stage juveniles per cm3 soil and growth of spinach cv. Symphony F1 seedlings was tested under glasshouse conditions. A Seinhorst model [y = m + (1 − m)zP–T] was fitted to fresh top- and total plant-weight data for inoculated and control plants. Tolerance limits (T) of spinach cv. Symphony F1 to M. incognita race 1 for fresh top and total plant weights were 0·25 and 0·5 eggs and second-stage juveniles per cm3 soil, respectively. The minimum relative values for fresh top and total plant weights were zero in both cases at Pi ≥ 32 eggs and second-stage juveniles per cm3 soil. Root galling was least at low initial population densities and greatest at 16 eggs and second-stage juveniles per cm3 soil. Maximum nematode reproduction rate was 33·1-fold at the lowest Pi.

An account is given of strain-specific diagnostic methods currently adopted in Italy to detect alfalfa mosaic alfamovirus (AMV), cucumber mosaic cucumovirus (CMV) and tomato spotted wilt tospovirus (TSWV). These viruses are highly detrimental to tomato crops as the introduction of new virus strains has deeply changed the population structure of resident viruses. RT-PCR coupled with restriction analysis of amplicons proved suitable for differentiating CMV and AMV strains whereas single-stranded conformational polymorphism (SSCP) was used for the identification of TSWV isolates. Application of strain-specific diagnostic methods to phytosanitary inspection of plant propagules is suggested as a powerful tool for timely identification of new virus strains

4 pages, 2 figures., High infection rates of olive feeder roots and soil infestation by the cyst-forming nematode Heterodera mediterranea were found in commercial olive orchards cv. Manzanilla established in sandy soils at two localities of Sevilla Province of Andalucía, southern Spain. No disease symptoms were noted on the aboveground plant parts, but slightly distorted feeder roots and necrotic areas were observed near the infection points. Sedentary juvenile stages and adult females showed a semi-endoparasitic feeding habit. Histopathological studies of infected olive roots showed a disease response typical of cyst nematode infection of susceptible hosts. Nematode feeding induced syncytial formation involving cellular alterations in the cortex, endodermis, pericycle, and vascular parenchyma tissues in both cortical and endodermal root cells. Additional keywords: cyst nematodes, host-parasite interaction, Research was supported in part by grant OLI96-2131 from Comisión Interministerial de Ciencia y Tecnología (CICYT) of Spain, and Joint Research Program Consejo Superior de Investigaciones Científicas (CSIC)-Consiglio Nazionale delle Ricerce (CNR).

The camellia root-knot nematode Meloidogyne camelliae was detected in Italy parasitizing roots of Japanese camellia (Camellia sasanqua) flowering bonsai trees imported from Japan, and it represents a new record for Europe.Morphology and morphometrical traits analysis of the intercepted population of M. camelliae were in agreement with those of the original description of the species, except for some minor differences in second-stage juvenile stylet length and c ratio, spicules and gubernaculuminmales, which may be a result of intraspecific variability. Integrative molecular data for this species were obtained using D2¿D3 expansion segments of 28S rDNA, ITS1¿rDNA, and the protein¿coding mitochondrial gene COI. The phylogenetic relationships of this species with other representatives of Meloidogyne spp. using D2-D3 expansion segments and ITS1 indicated that M. camelliae clustered together with M. artiellia and M. baetica. Histological observations of C. sasanqua feeder roots infected by M. camelliae reveal slight swellings of the root feeding sites, and most egg¿laying females protruding from the root. The anatomical alterations at feeding sites consist of 3¿8 hypertrophied, polinucleate giant cells/female, but no hyperplasia was induced unlike what commonly occurs for most members of the genus.

The Japanese cyst nematode Heterodera elachista was detected parasitizing corn cv Rixxer in Bosco Mesola (Ferrara Province) in Northern Italy. The only previous report of this nematode was in Asia (Japan, China and Iran) attacking upland rice; being this work the first report of this cyst nematode in Europe, and confirmed corn as a new host plant for this species. Integrative morphological and molecular data for this species were obtained using D2-D3 expansion regions of 28S rDNA, ITS1-rDNA, the partial 18S rDNA, the protein-coding mitochondrial gene, cytochrome oxidase c subunit I (COI), and the heat-shock protein 90 (hsp90). Heterodera elachista identified in Northern Italy was morphologically and molecularly clearly separated from other cyst nematodes attacking corn (viz. H. avenae, H. filipjevi, H. delvii, H. oryzae, H. sacchari, H. sorghi, H. zeae, Punctodera chalcoensis, and Vittadera zeaphila) and rice (H. oryzae, H. sacchari). The phylogenetic relationships of H. elachista from Northern Italy with other cyst-nematodes using rDNA and mtDNA showed a separation of the genus Heterodera in various morphospecies groups based on vulval cone structures. The development and parasitic habit of H. elachista on naturally infected corn cv Rixxer confirmed a typical susceptible reaction, including multinucleate syncytial cells in parenchymatic cells. Under greenhouse conditions, H. elachista successfully reproduced on two crops widely used in Northern Italy, such as corn (cv PR 33) and rice (cv Baldo). Considering the limited host-range of this nematode, that include two of the three world's most important crops, special attention is needed for avoiding the dispersal of this nematode into new areas, by movement of soil on equipment, water, and contaminated containers infested soil, or agricultural practices. © 2013 KNPV., The present work was supported with funds provided by the Italian Ministry of Economy and Finance to the National Research Council for the project “Innovazione e Sviluppo del Mezzogiorno-Conoscenze Integrate per Sostenibilità ed Innovazione del Made in Italy Agroalimentare-Legge n. 191/2009, and partially by grant AGR-136 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía and the European Social Fund.

A case of heavy infestation on tubers of three potato (Solanum tuberosum L) cultivars (Nicola, Spunta and Sieglinde) by the cyst nematode Globodera pallida Stone, 1973 was observed in Southern Italy on early producing potato cultivars in spring. Tubers were covered by white females and cysts but no other external symptoms were detectible on their surfaces. Detailed observations were directed to study the response of phellem and secondary cortex tissues induced by the expansion of syncytia during nematode feeding activity. The micro details of histological changes observed on serially sectioned infected tissues are described and illustrated. The nematode's feeding activity was confined to the outer part of the tuber while the host-parasite relationships were similar to those induced by the same nematode in the feeder roots.

The non-cyst forming heteroderid nematode Cryphodera brinkmani was detected in Italy parasitizing roots of Japanese white pine bonsai (Pinus parviflora) trees imported from Japan. Morphology and morphometrical traits of the intercepted population on this new host for C. brinkmani were in agreement with the original description, except for some minor differences on male morphology. Integrative molecular data for this species were obtained using D2-D3 expansion regions of 28S rDNA, ITS1-rDNA, the partial 18S rDNA, and the protein-coding mitochondrial gene, cytochrome oxidase c subunit I (COI). The phylogenetic relationships of this species with other representatives of non-cyst and cyst-forming Heteroderidae using ITS1 are presented and indicated that C. brinkmani clustered together with other Cryphodera spp. and with Meloidodera alni suggesting a monophyletic origin of non-cyst forming nematodes (Heteroderinae sensu Luc et al. 1978), which have been considered close to the ancestor of most species of Heteroderidae. Histological observations of P. parviflora feeder roots infected by C. brinkmani indicated that nematode females induce similar anatomical alterations to those reported for C. kalesari, consisting of formation of a single uninucleate giant cell (nurse cell) with hypertrophied nucleus, prominenet nucleolus, thickened cell wall and expanding into the stele and in contact of xylem, vacuum cambium and phloem. These findings are in agreement with the results of the phylogenetic analysis and indicate a close relationship in the plant responses induced by Cryphodera nematode females with those caused by the genetically related Meloidodera spp., which also induce formation of a uninucletate giant cell., The present work was supported with funds provided by the Italian Ministry of Economy and Finance to the National Research Council for the project “Innovazione e Svi-luppo del Mezzogiorno-Conoscenze Integrate per Sostenibilità ed Innovazione del Made in Italy Agroalimentare-Legge n.191/2009.

During nematode surveys in southern Spain and Italy 14 populations of Xiphinema species tentatively identified as Xiphinema americanum-group were detected. Morphological and morphometrical studies identified three new species and six known Xiphinema americanum-group species, viz.: Xiphinema parabrevicolle n. sp., Xiphinema parapachydermum n. sp., Xiphinema paratenuicutis n. sp., Xiphinema duriense, Xiphinema incertum, Xiphinema opisthohysterum, Xiphinema pachtaicum, Xiphinema rivesi, and Xiphinema santos. The Xiphinema americanum-group is the most difficult Xiphinema species group for diagnosis since the morphology is very conservative and morphometric characters often overlap. This group includes vectors of several important plant pathogenic viruses that cause significant damage to a wide range of agricultural crops. Molecular characterisation of these species using D2-D3 expansion regions of 28S rRNA, 18S rRNA, ITS1-rRNA and the protein-coding mitochondrial gene, cytochrome oxidase c subunit 1 was carried out and maximum likelihood and Bayesian inference analysis were used to reconstruct phylogenetic relationships among these species and with other Xiphinema americanum-group species. © 2012 KNPV., This research was supported by grant AGL2009-06955 from ‘Ministerio de Ciencia e Innovación’ of Spain, grant AGR-136 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and the European Social Fund.

The biological and molecular characterization is reported of a Watermelon mosaic virus isolate, denoted WMV-Le, associated with a necrotic phenotype of watermelon plants grown in the Provinces of Lecce and Taranto (Apulia, southern Italy). The fully sequenced WMV-Le genome consists of 10,045 nucleotides and is 99.1% similar to that of WMV-C05-270, a French isolate from melon of the WMV molecular group 3. Using recombination detection program RDP3, putative recombination breakpoints were identified close to nucleotide positions 42 to 1892, covering the 5′UTR/P1/HC-Pro region. The event represents the insertion of a sequence fragment of an isolate similar to WMV-FBR04-37 in the background of an isolate similar to WMV-FMF00-LL1. The field symptomatology was reproduced in watermelon plants grown in an experimental greenhouse but the virus induced severe symptoms also in Cucumis sativus, C. melo, Cucurbita maxima and C. pepo .

Over 70 species, belonging to 33 genera, of plant parasitic nematodes have been reported in association with olive. Several species of Helicotylenchus have been observed to cause root necrosis and considered capable of affecting olive tree growth. Three species of Meloidogyne (M. incognita, M. lusitanica and M. javanica) were responsible for heavy galling and growth retardation in inoculation trials and natural infestation. Pratylenchus vulnus has been demonstrated in inoculation trials as a potential pathogen of olive. Xiphinema species commonly occur around olive roots and X. elongatum has been shown to affect olive plant growth. Several sedentary plant nematodes attack olive. Tylenchulus semipenetrans infects olive in California (US) and Italy. Trophotylenchulus saltensis was described from olive roots in Jordan and a cyst nematode, Heterodera mediterranea, was shown to feed and multiply on olive roots. The cortical feeding cells of roots fed upon by Gracilacus peratica showed thickened and lignified wall near the penetration points of the stylet and those exposed to Ogma rhombosquamatum also presented hypertrophic nuclei and nucleoli. Rotylenchulus macrodoratus induces the formation of an enlarged mononucleate stelar or cortical ‘nurse cell’ with dense cytoplasm and hypertrophic nucleolus.

7 pages., Stunted growth of sweet basil (cv. Genovese) associated with large patches and severe soil infestations by the root-knot nematode Meloidogyne arenaria race 2 were observed in open fields at the end of the crop-growing season in Albenga, province of Savona, Northern Italy by early September 2007. Observed morphological traits of nematode life stages and results of analysis of isozyme electrophoretic patterns and differential host tests were used for nematode species and race identification. Nematode-induced mature galls (either in naturally infected plants or in artificially inoculated root tissues) were spherical or ellipsoidal and confluent along the root axis, containing usually several females, males, and egg-masses with eggs. Feeding sites were characterized by the development of giant cells that contained several hypertrophied nuclei and nucleoli. Giant cell cytoplasm was aggregated along the thickened cell walls. Vascular elements within galls appeared disorganized and disrupted. Due to the heavy damage observed, the relationships between the initial population density and growth of basil plants was also tested in a greenhouse experiment in which inoculum levels varied from 0 to 512 eggs and juveniles/cm3 of soil. Height and top fresh weight data of the inoculated and control plants was fitted to Seinhorst's model. Tolerance limits with respect to plant height and fresh top weight of basil cv. Genovese plants to M. arenaria race 2 were estimated as 0.15 eggs and juveniles/cm3 of soil. The minimum relative values (m) for plant height and top fresh weight were 0.39 and 0.19 at initial nematode population density (Pi) ≥16 eggs and juveniles/cm3 of soil, respectively. The maximum nematode reproduction rate (Pf/Pi) was 448.7 times at an initial population density of 4 eggs and second-stage juveniles/cm3 of soil.

7 pages, 2 figures., Pathogenicity and host-parasite relationships in root-knot disease of celery (Apium graveolens) caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Naturally and artificially infected celery cv. D'elne plants showed severe yellowing and stunting, with heavily deformed and damaged root systems. Nematode-induced mature galls were spherical and/or ellipsoidal and commonly contained more than one female, males and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. The cytoplasm of giant cells was aggregated along their thickened cell walls and consequently the vascular tissues within galls appeared disrupted and disorganized. The relationship between initial nematode population density (Pi) and growth of celery plants was tested in glasshouse experiments with inoculum levels that varied from 0 to 512 eggs and second-stage juveniles (J2) mL−1 soil. Seinhorst's model y = m + (1 – m)z^(P–T) was fitted to height and top fresh weight data of the inoculated and control plants. The tolerance limit with respect to plant height and fresh top weight of celery to M. incognita race 1 was estimated as 0·15 eggs and J2 mL−1 soil. The minimum relative values (m) for plant height and top fresh weight were 0·37 and 0·35, respectively, at Pi ≥ 16 eggs and J2 mL−1 soil. The maximum nematode reproduction rate (Pf/Pi) was 407·6 at an initial population density (Pi) of 4 eggs and J2 mL−1 soil.

7 pages., In the past, the distribution of Meloidogyne hispanica, the Seville root-knot nematode, appeared to be restricted to the southern part of Spain and Prunus spp.; however, its distribution has been confirmed to be worldwide because it occurs in all continents (Europe, Africa, Asia, Australia, and North, Central, and South America). Differentiation of M. hispanica from other Meloidogyne spp., mainly M. arenaria, can be very difficult using morphological and biological traits data. These species are quite similar and can be regularly confused in inaccurate taxonomic comparisons. In this study, species-specific polymerase chain reaction (PCR) and phylogenetic analysis of sequences from three ribosomal (r)DNA regions (18S, internal transcribed spacer [ITS]1-5.8S-ITS2, and D2-D3 of 28S) were used to characterize three M. hispanica isolates from different geographical origins (Brazil, Portugal, and Spain). Molecular analyses showed identical sequences for all three isolates for the three rDNA regions. Maximum parsimony analysis of the three rDNA regions and the species-specific PCR demonstrated and supported the differentiation of M. hispanica from M. incognita, M. javanica, and M. arenaria and from all described root-knot nematode species.

Stunted growth of fall-sown sugar beets (Beta vulgaris) associated with high incidence of crownroot infections and large soil infestations by Ditylenchus dipsaci were observed at the end of the crop growing season in southern Spain by early June 2005. The largest proportion (75%) of the nematode life-stages in plant and soil was the fourth-stage juvenile. The large number (up to 3,750 nematodes per gram of fresh tissue) of D. dipsaci individuals and severe anatomical alterations observed in storage sugar beet roots suggest that the stem and bulb nematode is the causal agent of the impaired growth of sugar beets observed in commercial fields. Observed morphological traits of nematode specimens and results of specific polymerase chain reaction (PCR) and phylogenetic analyses confirmed that the population of D. dipsaci infecting sugar beet belongs to the normal (nongiant) biological type of the nematode. Results of host-range bioassays indicated that the population of D. dipsaci infecting sugar beet in southern Spain reproduces on pea (including seeds and pods), onion, potato, spinach, and tomato, but not on bean, cotton, maize, and tobacco. These results indicate that D. dipsaci may be an important constraint for sugar beet crops in the affected area, but also for other important crops commonly used in rotation with them.

Broomrapes (Orobanche spp., Orobanchaceae) are chlorophyll-lacking, obligately parasitic flowering plants that infect roots of many dicotyledoneous species and cause severe damage to vegetable and field crops worldwide, but particularly in North Africa, southern and eastern Europe, and the Middle East. (1). Orobanche crenata is one of the most important broomrapes and mainly infects legume crops (2). In January 2006, we observed severe broomrape attacks in four commercial fields of fall-sown lettuce (Lactuca sativa cv. Iceberg) crops at Almodóvar del Río (Córdoba Province) in southern Spain. Infected lettuce plants showed severe stunting, foliar yellowing, and had loose-formed heads. Infection of lettuce plants by Orobanche sp. was confirmed by removing plants to verify the attachment of broomrapes to lettuce roots. There were one to four broomrapes per lettuce plant. Incidence of infected lettuce ranged from 10 to 20% in different areas of the fields. Morphological observations of broomrape plants identified the parasite as O. crenata. The main botanical features were as follows: plants 20 to 40 cm tall; corolla 20 to 28 mm, white, lips with lilac, divergent veins, lower lip large with suborbicular lobes, not ciliate; filaments hairy, obliquely inserted 2 to 4 mm above the base of corolla, with short glandular hairs in the upper third; anthers glabrous, 2 to 2.5 mm in length, and stigma yellow or pinkish at anthesis (2). O. crenata also was observed infecting faba bean (Vicia faba) plants in a field in close proximity to the affected lettuce fields. The complete 5.8S ribosomal DNA gene and internal transcribed spacers (ITS) 1 and 2 of O. crenata were sequenced using adventitious roots and stem tissues sampled from infected faba bean and lettuce plants (Genbank Accession Nos. DQ458908 and DQ458909) by standard protocols (3). A nucleotide BLAST search revealed that both sequences were identical and share 100% similarity with three reported ITS1-5.8S-ITS2 sequences from two Orobanche spp. (O. crenata and O. minor; Genbank Accession Nos. AY209267, AY209266, and AY209272). On the basis of the morphological characters described above, the parasite was O. crenata and not O. minor. O. crenata has been reported infecting many legume crops in southern Spain, including faba bean, pea, lentil, and vetch. To our knowledge, this is the first report of O. crenata infecting lettuce in Spain and elsewhere. The high incidence of O. crenata on legume crops, and the severe infections found on lettuce plants suggest that this parasitic plant may be an important constraint for fall-sown lettuce in southern Spain.

8 pages, 5 figures.-- PMID: 18943038 [PubMed].-- Available Open Access at the publisher site., Root-knot nematodes (Meloidogyne spp.) are sedentary, obligate endoparasites in plants, where they induce specialized feeding sites. The feeding sites act as strong metabolic sinks to which photosynthates are mobilized. The histopathological modifications in the nematode-induced feeding sites of artificially inoculated chickpea cv. UC 27 were qualitatively and quantitatively compared using five isolates of M. artiellia and one isolate each of M. arenaria, M. incognita, and M. javanica. All Meloidogyne isolates infected chickpea plants, but root gall thickening was significantly less for M. artiellia isolates than for the other Meloidogyne species. Nevertheless, neither the number of giant cells in the feeding site (averaging four to six) nor the area of individual giant cells was influenced by nematode species or isolate. However, the number of nuclei per giant cell was significantly smaller, and the maximum diameters of nuclei and nucleoli were significantly greater, in giant cells induced by M. artiellia isolates than in those induced by M. arenaria, M. incognita, or M. javanica. In a second experiment, M. artiellia induced giant cells in faba bean and rapeseed also contained a small number of large nuclei., This research was supported by grant AGL2003-00640 from Comisión Interministerial de Ciencia y Tecnología (CICYT), Ministerio de Educación y Ciencia of Spain.

full text: http://www.ias.csic.es/pcastillo/journal%20of%20phytopathology_152_229-234.pdf, Fifteen populations of cyst-forming nematodes belonging to 11 known and one unidentified species collected in countries bordering the Mediterranean Sea were studied using polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP) and internal transcribed spacer (ITS)-rDNA sequences. RFLP profiles generated by the restriction enzymes AluI, AvaI, Bsh1236I, HaeIII, Hin6I, MvaI, PstI and RsaI are presented for Heterodera carotae, H. ciceri, H. fici, H. filipjevi, H. goettingiana, H. hordecalis, H. humuli, H. mediterranea, H. ripae and H. schachtii. Molecular data support the first detection of H. filipjevi from wheat in Italy and H. ripae from nettle in Greece. A relative high level of sequence divergence between populations of H. hordecalis was observed. This suggests that two species might presently be grouped under this taxon. The phylogenetic relationship between the Mediterranean cyst-forming nematode species is analysed based on the ITS-rDNA sequences.

High infection rates of wild olive (Olea europaea sp. sylvestris) feeder roots and soil infestation by a new root-knot nematode were found in sandy soil at Vejer de la Frontera (Cádiz), southern Spain. Morphometric traits and analyses of the nematode esterase electrophoretic pattern as well as of the internal transcribed spacer 1 (ITS1)-5.8S gene and D2-D3 fragment of the 28S gene of rDNA showed that specimens differed clearly from known root-knot nematodes. Studies of host–parasite relationships showed a typical susceptible reaction in naturally infected wild olive plants and in olive planting stocks (cvs. Arbequina and Picual) artificially inoculated with the nematode. However, the nematode did not reproduce in artificially inoculated chickpea, pea, and tomato. Because of the ability of this new nematode to infect wild and cultivated olives only, we suggest the common name, "Mediterranean olive root-knot nematode". The species is herein described and illustrated, and named as Meloidogyne baetica n. sp. The new root-knot nematode can be distinguished from other Meloidogyne spp. by (i) the perineal pattern, which is almost similar to that of M. artiellia, characterized by distinct inner striae forming two distinct longitudinal bands, extending throughout the perineum to just below the vulva; (ii) female excretory pore anterior to the level of stylet knobs, excretory pore distance from anterior end/length of stylet ratio extremely small (0.5 to 0.8); and (iii) second-stage juveniles with elongate-conoid tail. Phylogenetic trees derived from maximum parsimony analyses showed that M. baetica is closely related to M. artiellia, the cereal and legume root-knot nematode., Research was supported in part by a Bilateral Research Program funded by Consejo Superior de Investigaciones Científicas (CSIC), Spain, and Consiglio Nazionale delle Ricerche (CNR), Italy.

Four populations of Pratylenchus thornei from different locations were tested for reproductive fitness in axenic carrot disc cultures and for pathogenicity to chickpea cultivars JG 62 and UC27 and lines K850 and ILC 1929. Parasitism and histopathology on selected chickpea genotypes (JG 62, UC27 and lines ILC 482, ICC 11324 and ICC 12237) were also investigated. Reproductive fitness, assessed as the ratio of the final number of nematodes per carrot disc to the number of nematodes inoculated, was similar among the populations tested and the four populations reproduced to a similar extent in a given chickpea genotype. However, the extent of reproduction was significantly affected by the chickpea genotype, JG 62 and UC27 being the best and poorest hosts, respectively. Pathogenicity to chickpea genotypes was assessed by the difference in fresh root and dry shoot weights between infected and uninfected plants 90 days after inoculation. Plant growth was significantly reduced by the four nematode populations in all chickpea genotypes, with the exception of cv. JG62, which was tolerant of P. thornei. Severity of root necrosis caused by nematode infection was similar for all populations. Histopathological studies of chickpea genotypes infected by P. thornei showed that all were suitable hosts according to nematode reproduction and host reaction. P. thornei always migrated through epidermal and cortical cells by breaking down cell walls along the nematode pathway. In the most susceptible lines (ILC 482 and JG 62), damage to endodermal cells adjacent to nematode feeding sites was occasionally observed., Research was supported in parts by grant AGF97-1479 from Comisión Interministerial de Ciencia y Tecnología (CICYT) of Spain, and Joint Research Program Consejo Superior de Investigaciones Científicas (CSIC)–Consiglio Nazionale delle Ricerce (CNR) for 1995–96. The authors thanks Drs N. Greco and M. Di Vito, CNR, Bari, Italy, for providing us with the population of P. thornei from Syria.

Pratylenchus thornei-chickpea interactions were investigated under controlled and fluctuating environmental conditions in the growth chamber, greenhouse and shadehouse. Under controlled conditions. P. thornei infected chickpea hnes 12071/10054 and P2245 and cultivars Andoum 1, JG62 and UC 27. Line P 2245 and cv. JG 62 were the most susceptible genotypes on the basis of root damage and nematode reproduction, but nematode infection did not significantly reduce root and shoot weights. Cultivars Andoum 1 and UC27 and line 12071/10054 showed the least root damage and nematode reproduction. Inoculation of cv. Andoum 1 with 2500, 5000 or lOOOO nematodes per plant in pots did not affect shoot weight, regardless ofthe conditions of water stress ofthe plants. However, root weight was significantly reduced by nematode infection in plants grown under water stress and fluctuating temperature conditions in the greenhouse, but was not affected by any other treatment. The nematode reproduction index was not affected by soil water content under shadehouse conditions, but was greater on plants watered to soil water-holding capacity than in water-stressed plants under greenhouse conditions. For both environments, the nematode reproduction index decreased when inoculum density was greater than 5000 nematodes per plant., This research was supported by grant AGF92- 0910-CO2-01 from Comision Interministerial de Ciencia y Technologia (CICYT), We thank H, M, Halila, INRA, Tunisia for providing us with seeds of cultivar Andoum 1, and F, Orgaz, Instituto de Agricultura Sostenible, CSIC, Spain for measuring water potential.

Most aspects of the eco-biology of OLV2 are still unclear (e.g. vector transmission, isolate variability, natural host range). OLV2 was previously detected in wild castor bean in Greece (Vovlas et al., 2002); we have described in Italy a disease caused by another OLV2 isolate in the same host. This new finding might suggest a potential role of castor bean in the epidemiology of OLV2, by acting as a natural virus reservoir.

Tomato necrosis devastated the tomato crop in the Basilicata region of Italy in 1988. Several hundred tomato (Lycopersicon esculentum) seedlings representing the cultivars UC82B, Rutgers, Bandera, and Italpeel were preventively inoculated or vaccinated with cucumber mosaic virus (CMV) strain S containing the nonnecrogenic satellite S-CARNA 5 (CMV-associated RNA 5) and placed in a commercial tomato field in the Basilitica region of southern Italy to test for protection against tomato necrosis. When surveyed in July 1989, the protective effect of the vaccination was greater than 95%. The fruit yields from the protected plants were double those of the nonprotected controls (.)

An isometric virus was isolated from cucumber plants growing in a plastic house in Crete and showing stunting and bright yellow mosaic of the leaves. Based on host range, properties in crude sap, behaviour during purification, electron microscopy and serology, the virus was identified as an isolate of artichoke yellow ringspot nepovirus. Ecological data corroborate transmission of the virus via the soil.

A virus with filamentous particles 697 nm in length was isolated from artichoke plants in Southern Italy and identified as a new possible member of Carlavirus group, for which the name artichoke virus M (AVM) is suggested. AVM could not be transmitted by sap inoculation to herbaceous hosts and was always present in artichoke in mixed infections with other viruses. Virus particles had a buoyant density in CsCl of 1.31 g × cm−3 and contained a single species of nucleic acid with an apparent size of 7.5 Kb and a single coat protein species with a mol. wt of 31,000. The virus was distantly related serologically to carnation latent and poplar mosaic carlaviruses but not to other members of the group including the recently described artichoke latent S carlavirus. Cytological alterations consisted of complex cytoplasmic inclusions composed of deranged organelles, lipid droplets and accumulations of membranes.

An isometric virus c. 30 nm in diameter with a single RNA species (mol.wt 1.45 × 106) isolated from cucumber plants from the island of Crete (Greece) is described under the name of cucumber fruit streak virus (CFSV). The most evident symptom on naturally infected plants consisted of longitudinal chlorotic streak of the fruits. In glasshouse, the virus was soil-transmitted to C. sativus, and, mechanically, to a wide range of herbaceous hosts, most of which were infected only locally. Purified virus preparations sedimented as a single component with sedimentation coefficient of 132S. At equilibrium these preparations were homogeneous in CsCl gradients but formed two bands in Cs2SO4 gradients. Virus particles were stabilized by forces involving divalent cations, pH-dependent bonds and salt links between protein and RNA. Although some of the properties of CFSV are similar to those of other small spherical viruses with single RNA species there are differences which do not allow for the assignment of the virus to any of established taxonomic group of plant viruses.

CYMV-T, CYMV-C and CYMV-RS are three strains of CYMV, a nepovirus isolated from chicory in Southern Italy. They are serologically indistinguishable, but display different electrophoretic and analytical ultracentrifugation patterns. In fact the RNAs obtained from CYMV-T, when analyzed in 2.4% polyacrylamide cylindrical gels, showed the presence of a 170,000 mol. wt. satellite-like RNA (CYMV-T Sat RNA) and several other RNAs, whereas CYMV-RS gave only the genomic RNAs and CYMV-C, in addition, some ofthe RNAs present in CYMV-T but not the Sat RNA. When these three strains were assayed on Nicotiana glutinosa L., CYMV-C and CYMV-RS elicited typical necrotic rings, whereas CYMV-T infections were symptomless. The conclusions were drawn that CYMV-T Sat RNA is another low mol. wt. RNA able to display viral disease regulation and that CYMV-T, CYMV-C and CYMV-RS could represent an example of natural oscillation among different stages of RNA satellite emergence.

During a nematode survey, severe infections of tobacco feeder roots and heavy soil infestations by Meloidogyne incognita race 1 were found in S. Miguel (Azores islands, Portugal). This is thought to be the first record of M. incognita infection of tobacco in Azores. The morphology of various life stages, analysis of the esterase electrophoretic pattern and differential host tests were used for nematode characterization and identification. Nematode-induced mature galls were spherical and/or ellipsoidal and usually contained more than one female, males and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. Giant cell cytoplasm was aggregated along a thickened cell wall. Vascular tissues within galls appeared disorganized. The relationship between the initial nematode population density and growth of tobacco plants was tested in a glasshouse experiment in which inoculum levels varied from 0 to 512 eggs and juveniles (J2) cm-3 of the soil. Seinhorst's model was fitted to height and top fresh weight data of the inoculated and control plants. Tolerance limits with respect to plant height and fresh top weight of tobacco cv. Erzegovina plants to M. incognita race 1 were estimated as 1.25 eggs and J2 cm-3 of the soil. The maximum nematode reproduction rate was 404.7 at an initial population density of 4 eggs and J2 cm-3 of the soil.