Amb a 1-linked CpG oligodeoxynucleotides reverse established airway hyperresponsiveness in a murine model of asthma

BACKGROUND

Recently, it has been demonstrated that immunostimulatory DNA sequences (ISS) containing CpG motifs prevent the development of allergic airway responses in murine models of disease. However, few studies have addressed the issue of whether these agents will reverse established Tm(H)2-driven allergic airway responses.

OBJECTIVE

The aim of this study was to determine whether intradermal delivery of an immunogenic protein of ragweed pollen linked to an immunostimulatory DNA sequence could reverse an established allergic response in the mouse lung.

METHODS

Mice sensitized and challenged with ragweed pollen extract were treated intradermally twice at 1-week intervals with an ISS chemically linked to Amb a 1 (Amb a 1-ISS). One week after the Amb a 1-ISS treatment, mice were rechallenged intratracheally with ragweed extract, and airway responses were assessed.

RESULTS

Amb a 1-ISS treatment of ragweed-sensitized and ragweed-challenged mice significantly reversed allergen-induced airway hyperresponsiveness and suppressed the total number of eosinophils in bronchoalveolar lavage fluid. The inhibitory effect of Amb a 1-ISS was associated with a marked increase in IFN-gamma levels by Amb a 1-stimulated splenocytes and a shift in the antibody profile from a T(H)2-directed IgG1 response to a T(H)1-directed IgG2a response. Interestingly, the inhibitory effect of Amb a 1-ISS on allergen-driven airway hyperresponsiveness was independent of suppression of T(H)2 cytokine production.

CONCLUSION

These results demonstrate that intradermal delivery of allergen-specific DNA conjugates can reverse established allergic responses in the murine lung, supporting their potential use in the treatment of human asthma.

Immunostimulatory sequence DNA linked to the Amb a 1 allergen promotes T(H)1 cytokine expression while downregulating T(H)2 cytokine expression in PBMCs from human patients with ragweed allergy

BACKGROUND

Recent studies have demonstrated that bacterially derived immunostimulatory sequences (ISSs) of DNA can activate the mammalian innate immune system and promote the development of T(H)1 cells. Promotion of T(H)1 immunity by means of immunotherapy in allergic patients has led to the alleviation of symptoms that result from allergen-specific T(H)2 responses.

OBJECTIVE

Our purpose was to investigate whether the T(H)1-enhancing properties of ISSs could be used to alter the T(H)2-dominated immune response of allergic PBMCs in vitro.

METHODS

Ragweed protein-linked ISS (PLI) was generated from a specific, highly active 22-base ISS and Amb a 1, the immunodominant allergen in ragweed pollen, to combine the T(H)1-enhancing properties of ISSs with allergen selectivity, and its activity was investigated in PBMC cultures from subjects with ragweed allergy.

RESULTS

PLI was markedly successful at reversing the dominant allergen-induced T(H)2 profile while greatly enhancing IFN-gamma production. Delivering ISSs in a linked form proved to be much more effective at modulating the resulting cytokine profile than delivering free ISSs in a mixture with unlinked Amb a 1. PLI also demonstrated cytokine-modulating properties, even when used to stimulate cells that had already been primed for 6 days with Amb a 1. The antigen specificity of the action of PLI was confirmed by the observations that PLI enhances Amb a 1--specific T-cell proliferation.

CONCLUSION

These data indicate that delivery of ISSs within an antigen-specific context exhibits potent cytokine-modulating activity and, combined with its reduced allergenicity, makes this molecule a strong candidate for use in improved immunotherapy applications.

Colophonium and Compositae mix as markers of fragrance allergy: Cross-reactivity between fragrance terpenes, colophonium and Compositae plant extracts

The aim of this study was to assess the strength of any association between sensitization to 'new' fragrance compounds and sensitization to Compositae, fragrance mix, Myroxylon pereirae resin and colophonium, respectively. Consecutive eczema patients were tested with a series of essential oils and selected fragrance compounds and another series of oxidized terpenes in connection with European multicentre fragrance projects. Contact allergy to either series was frequently detected, in 5% of 318 and 4.6% of 262 persons tested, and both had a statistically significant association with Compositae, colophonium and fragrance mix sensitization. The individual results indicated that simultaneously occurring positive reactions to essential oils, colophonium and Compositae were based on cross-reactivity rather than concomitant sensitization. Thus, all patients with positive reaction to the rare fragrance sensitizer beta-caryophyllene had positive colophonium reactions, and cross-reactivity between essential oils and Compositae was related to the Compositae plant extracts of the Compositae mix and not the pure sesquiterpene lactones of the standard series. The implication is that Compositae mix and colophonium may be markers of fragrance allergy, which is important to know when assessing the relevance of positive reactions to Compositae plant extracts and colophonium.

Airborne Compositae dermatitis: monoterpenes and no parthenolide are released from flowering Tanacetum parthenium (feverfew) plants

The air around intact feverfew (Tanacetum parthenium) plants was examined for the presence of airborne parthenolide and other potential allergens using a high-volume air sampler and a dynamic headspace technique. No particle-bound parthenolide was detected in the former. Among volatiles emitted from the aerial parts of feverfew plants and collected by the dynamic headspace technique a total of 41 compounds, mainly monoterpenes, were identified and quantified by GC and GC-MS. Alpha-Pinene, camphene, limonene, gamma-terpinene, (E)-beta-ocimene, linalool, p-cymene, (E)-chrysanthenol, camphor and (E)-chrysanthenyl acetate were the predominant monoterpenes accounting for nearly 88% of the total volatiles emitted. The average total yield of volatiles emitted over 24 h was 18,160 ng/g fresh weight of leaves and flowers, corresponding to the emission of approximately 8 mg volatiles per day from one full-grown feverfew plant. No parthenolide or other sesquiterpene lactones were detected. The present investigation does not support the theory of airborne sesquiterpene lactone-containing plant parts or of direct release of sesquiterpene lactones from living plants as the only explanations for airborne Compositae dermatitis. Potential allergens were found among the emitted monoterpenes and their importance in airborne Compositae dermatitis is discussed.

Routine patch testing with the sesquiterpene lactone mix in Europe: a 2-year experience. A multicentre study of the EECDRG

To test the screening value of the sesquiterpene lactone (SL) mix in Europe today and describe epidemiological and clinical features of Compositae-sensitive patients, the SL mix 0.1% pet. was included in the standard patch test series in 11 European clinics. 10,695 patients were tested, and 106 (1%) had positive reactions, 74% of which were of current or old relevance. The prevalence of positive reactions varied between 0.1 and 2.7% in different centres. The median age of the 66 females was 51.5 years, and 55.2 in the 40 males. The 20 occupationally sensitized had a higher % of males and a median age of 43 years, whereas 7 UV-sensitive patients had a median age of 72 years. Garden plants were the major suspected sensitizers and the clinical patterns were partly, in accordance with plant dermatoses in general, involving hands, forearms and face, and partly widespread eczema in a large proportion of the patients. More than 1/3 were positive to perfume and/or colophony, possibly reflecting cross-reactivity. With only 1 case of active sensitization and no irritant reactions, the SL mix is a safe allergen and the overall prevalence of positive reactions supports its continued use in the standard patch test series.

Asteraceae species as potential environmental factors of allergy

The statistics from Europe and the USA have proven a high risk for skin diseases associated with plant contact. Therefore, plant-induced dermatitis is of increasing attention in dermatology. The focus of this paper was to present the current knowledge on aspects of contact allergy related to Asteraceae (Compositae) species. The Asteraceae family is one of the largest in the world with members across all continents. The PubMed/Medline databases have been searched. The Asteraceae representatives consist of diverse secondary metabolites, which exhibit various advantageous effects in humans. In particular, sesquiterpene lactones (SLs) may cause sensitization resulting in skin irritation and inflammation. In this study, we tried to reveal the allergenic potential of several Asteraceae species. The Asteraceae-related allergy symptoms involve eczema, hay fever, asthma, or even anaphylaxis. Furthermore, the evidence of severe cross-reactivity with food and pollen allergens (PFS) in patients sensitive to Asteraceae allergens have been announced. Further identification and characterization of secondary metabolites and possible allergens in Asteraceae are necessary for the better understanding of Asteraceae-related immune response. The Asteraceae allergy screening panel (the SL mix and the Compositae mix of five plant species) is a promising tool to improve allergy diagnostics and therapy.

Characterization of polyclonal allergen-specific IgE responses by affinity distributions

Polyclonal IgE responses have been previously characterized by allergen-specific antibody levels and by identification of amino acid sequences related to immunodominant epitopes. However, the binding affinities related to these antibody families are not well known. Using sera from donors with known sensitivities to ragweed or house dust mite allergens, we studied the binding reactions between the purified allergens Amb a 1 and Der p 1 and allergen-specific IgE's by determining affinity distribution functions. The distributions of binding affinities only exhibited a few dominant reactions indicated by peaks in an affinity distribution display. In all the donors tested, there were two dominant peaks and in 2/3 of the cases there was a third peak for both Amb a 1 and Der p 1. We further characterized the polyclonal interactions between IgE and Der p 1 by inhibiting the specific binding of IgE using peptide fragments known to be constituents of Der p 1 epitopes. Each peptide inhibited only a single peak in the affinity distributions. It would appear that the peaks in the affinity distribution represent antibodies directed to single epitopes. These results suggest that in our atopic population the response is surprisingly uniform. The bulk of the IgE response (70-80%) is of high affinity (10(8)-10(11) M(-1)) and directed towards a few epitopes. The relative affinities towards epitopes seem to be determined by the structure of the epitope and not variations of individuals' immune responses.

Chlamydia trachomatis infection inhibits airway eosinophilic inflammation induced by ragweed

While much progress has been achieved in controlling infectious diseases, there is a startling increase in the prevalence of allergic disorders in developed countries. Previous studies using experimental murine models of asthma have demonstrated that mycobacterial infections are capable of suppressing asthma-like reactions induced by ovalbumin (OVA). Using a different intracellular bacterium, Chlamydia trachomatis mouse pneumonitis (MoPn), we examined the effect of infection on the development of allergic responses to a common natural airborne allergen, ragweed (RW). The data showed that airway eosinophilia induced by ragweed sensitization/challenge was significantly reduced in MoPn-infected mice. MoPn-infected mice also exhibited significantly lower levels of allergen-driven Th2 cytokine production, namely IL-4, IL-5, IL-10, and IL-13, following ragweed exposure in comparison with those treated with ragweed only. Additionally, the production of eotaxin, a C-C chemokine for eosinophil chemoattraction following RW exposure, was significantly reduced in the lungs of MoPn-infected mice. However, MoPn infection did not reduce the levels of RW-specific IgE and IgG1 production in the sera, nor did it diminish the level of total serum IgE. These data provide evidence that the suppression of the allergic airway inflammation induced by a common environmental allergen is attainable through intracellular bacterial infection.

[Compositae dermatitis]

INTRODUCTION

Compositae dermatitis is an allergic contact dermatitis caused by plant species of the Compositae family. The first report of a cutaneous reaction to the Chrysanthemum genus was made by Howe JS in 1887. In 1895 Maiden JH reported about skin lesions among men working with Tagetes minuta. Case reports of contact allergic-ragweed dermatitis appeared in the American literature as early as 1919. The North American feverfew--Parthenium Hysterophorus was brought to India from America in 1956 and it caused thousands of cases of so-called parthenium dermatitis. Ragweed and parthenium dermatitis became prototypes for the classic, so-called "airborne" Compositae dermatitis, that affects primarily exposed skin surfaces, and produces a universal erythroderma.

EPIDEMIOLOGY

The frequency of contact allergy to Compositae in Europe is higher than previously believed. It occurs most frequently in middle-aged and elderly persons, but also in all age groups. During the two past decades a more equal sex ratio has been established. The prevalence varies from 0.7-1.4% in the general population, up to 4.5% among occupationally exposed persons. Compositae allergy is among the top ten contact sensitivities in Europe. In North Europe plants were the cause of 4.4% cases of occupational allergic contact dermatitis. ETIOLOGY AND PATHOGENESIS: Among cultivated Compositae plants, Chrysanthemum is considered to be a major sensitizer in Europe (60%). Among the edible types, it is lettuce--Lactuca sativa and endive Cichorium endivia (20-30%), and wild-growing feverfew--Tanace--tum parthenium (70-90%), tansy--Tanacetum vulgare (54%), and dandelion--Taraxacum officinale (65%). Sesquiterpene lactones are the main sensitizers of the Compositae family. Other components, thiophenes and acetylenes are said to elicit only phytophotodermatitis, but recent studies have demonstrated that some thiophenes and benzofuran derivates possess not only phototoxic activity, but also sensitizing properties. Photosensitivity is present in 22-75% Compositae sensitive individuals. Extracts from Compositae are known to be phototoxic in vitro. Photoreactivity of alpha-methylene-gamma-la-ctone group of sesquiterpene-lactone directed towards the DNA base thymine, thus producing intermolecular 2 + 2 photoadducts (antigen within the cell), was also thought to be related to photosensitivity. Clinical manifestations vary from generalized eczema (20-30%), eczema of hands and face (24%), hand (36-44%), or facial eczema (11-28%). 65% of patients have vesicular hand eczema.

DIAGNOSIS

Routine patch testing with sesquiterpene lactone mix, aimed testing with Compositae extracts screening mix, Compositae plants, and with their extracts, whereas the treatment of choice is a specific allergen-immunotherapy.

Bee pollen sensitivity in airborne pollen allergic individuals

BACKGROUND

Physicians who practice alternative medicine often prescribe bee pollen as a food supplement and a treatment for various ailments.

OBJECTIVES

To determine the qualitative and quantitative composition of bee pollen and to investigate the cutaneous reactivity of atopic patients to bee pollen extracts.

METHODS

The absolute number of pollen grains per gram of bee pollen was calculated, and morphologic identification of the botanical family was performed. Five extracts of bee pollen were prepared for skin prick testing, according to standard methods. Two hundred two volunteers participated in the study; 145 were atopic patients with respiratory allergy. The remaining 57 were healthy volunteers or nonatopic patients and served as a control group. All participants underwent skin prick testing with a standard battery of 6 aeroallergens (olive, grasses mix, Parietaria, mugwort, Dermatophagoides pteronyssinus, and Dermatophagoides farinae) and with all homemade bee pollen extracts.

RESULTS

All samples of bee pollen contained Oleaceae pollen in high concentrations. Small amounts of anemophilous pollen (Compositeae, Chenopodiaceae) were detected in various samples. A strong positive correlation was observed between cutaneous reactivity to bee pollen extracts and olive, grasses, and mugwort.

CONCLUSIONS

Bee pollen contains a large amount of pollen, which belongs to various allergenic families of plants. Bee pollen retains its allergenic potential as demonstrated by strong cutaneous responses to bee pollen extracts observed in atopic patients in contrast to nonatopic subjects. Regarding pollen allergic individuals, further studies are needed to evaluate the safety of ingesting large amounts of bee pollen.

Expression of IgH chain genes in antibody response to ragweed and purified Amb a 1: evidence for differential regulation of isotype production

A survey of the work with Ig response to allergens carried out previously reveals an allergen-specific response both by IgE and all of IgG subclasses. Response of non-sensitive people is characterized by the appearance of a variety of the IgG subclasses. We have reexamined ragweed and Amb a 1 specific Ig response in 54 nonsensitive and 147 atopic or atopic-allergic people using a new inverse sandwich immunoassay allowing discrimination based on antibody affinity. We show that non-sensitive people present no, 0 out of 54, Ig response with affinities higher than Ka 10(7) M(-1). The subpopulation of 66 atopics who never have experienced desensitization responds vigorously and solely (56 out of 66) with genes of the sequence gamma2-alpha2. Only ten showed an additional weak response from gamma1-alpha1. This suggests a possible association between the atopic state and selective activation of part of the gene sequence.

Immunodetection of Pectic Epitopes, Arabinogalactan Proteins, and Extensins in Mucilage Cells from the Ovules of Pilosella officinarum Vaill. and Taraxacum officinale Agg. (Asteraceae)

The main aim of this study was to compare the cytological difference between ovular mucilage cells in two Asteraceae species-Pilosella officinarum and Taraxacum officinale-in order to determine whether pectic epitopes, arabinogalactan proteins, or extensins are present. The immunocytochemical technique was used. Both the Taracacum and Pilosella genera have been used recently as models for understanding the mechanisms of apomixis. Knowledge of the presence of signal molecules (pectic epitopes, arabinogalactan proteins, and extensins) can help better understand the developmental processes in these plants during seed growth. The results showed that in Pilosella officinarum, there was an accumulation of pectins in the mucilage, including both weakly and highly esterified pectins, which was in contrast to the mucilage of Taraxacum officinale, which had low amounts of these pectins. However, Taraxacum protoplasts of mucilage cells were rich in weakly methyl-esterified pectins. While the mucilage contained arabinogalactan proteins in both of the studied species, the types of arabinogalactan proteins were different. In both of the studied species, extensins were recorded in the transmitting tissues. Arabinogalactan proteins as well as weakly and highly esterified pectins and extensins occurred in close proximity to calcium oxalate crystals in both Taraxacum and Pilosella cells.

The effect of 4α,5α-epoxy-10α,14-dihydro-inuviscolide, a novel immunosuppressant isolated from Carpesium abrotanoides, on the cytokine profile in vitro and in vivo

The plant Carpesium abrotanoides (CA) is used in Asian herbal medicines as an insecticide and to treat bruises. However, the effect of single compounds from CA blooms and the mechanism of its immunosuppressive effect remain poorly understood. The aim of this study was to investigate the mechanism of the immunosuppressive effect in the three kinds of immune cells, and the immunosuppressive effect of CA bloom extract (CAE) in acute inflammation models (LPS and ConA-induced inflammation). Interleukin-6, IL-4, IL-13, IFNγ, and IL-10-but not TNFα-were significantly reduced in a dose-dependent manner by 4α,5α-epoxy-10α,14-dihydro-inuviscolide (INV). Furthermore, INV inhibited NF-κB transcriptional activation and IL-10 promoter activity in the same manner as for Bay11. Meanwhile, treatment with dexamethasone reduced the levels of IFNγ, but not IL-10, and resulted in no change in NF-κB transcriptional activation or the IL-10 promoter. INV did not affect PMA-induced IκB kinase complex phosphorylation, IκB degradation, or MAPK and the nuclear translocation of p65, as with DEX. The in vivo, CAE has an immunosuppressive effect on the LPS-induced inflammation response model by inhibiting the plasma level of IFNγ and IL-6 levels. CAE treatment also tends to attenuate the plasma level of IFNγ, IL-4, and IL-6 in ConA-induced inflammation. These findings indicate that INV causes the reduction of the cytokine profile by blocking the NF-κB transcription factor activation and the molecular mechanism by which INV operates could provide new insights into the unique mechanisms responsible for NF-κB inhibition, in contrast to established immunosuppressants, as a therapeutic agent for immunopathological treatment.

Diagnostic Workup in IgE-Mediated Allergy to Asteraceae Weed Pollen and Herbal Medicine Products in Europe

Anemophilous weeds from the Asteraceae family are highly allergenic and represent a significant source of aeroallergens in late summer and autumn. Ragweed and mugwort pollen allergies have become a significant health burden in Europe. Some people with respiratory allergies to weed pollen may also suffer hypersensitivity reactions to herbal medicines obtained from certain cross-reactive plants in the Compositae family, such as chamomile, marigold, and purple coneflower. General physicians, ear, nose, and throat (ENT) specialists, and pulmonologists need to be familiar with the diagnostic tests used by allergists in clinical practice to support accurate diagnosis in such patients. Allergists must also be aware of the suggestions of the European Medicines Agency (EMA)'s Herbal Medicinal Products Committee and the broad spectrum of herbal therapies to educate their patients about potential risks.

[Clinical diagnostic assay of allergic patients with pollen extract from Parthenium hysterophorous L]

AIMS

There are no antecedents in Cuba of studies developed to prove the efficacy of on allergy test to pollen Parthenium hysterophorus L.

OBJECTIVE

Evaluate the allergenic extract pollen Parthenium hysterophorus L elaborated at the reference hospital William Soler City Havana.

MATERIAL AND METHODS

We selected 100 patients with a positive clinic history of inhalant allergy and 100 healthy person. All the persons selected were skin prick tested with dillution's of the extract (1:100 and 1:1000 P/V) and positive and negative control. We measured the average diameter of the wheal and the perpendicular diameter, then we calculated the average. We also calculated size of the wheal in the duplicated, which constituted the size of the reaction. We estimated the validity of the test calculating the sensibility and specificity. We used the EPITABLE program to do this.

RESULTS

The skin prick tested positive in 79% of the patients and 9% in the healthy persons, for a sensitivity of 79% the interval of confidence (IC), 69.5, 86.2 and specificity of 91%, IC 83.2, 95.5, the predictive positive value 89.8% IC 81.04, 94.9 and the predictive negative value 81.3%, IC 72.5, 87.8.

CONCLUSIONS

The allergenic extract of Parthenium hysterophorus L in very sharp to test the allergy to his pollen produced by the allergology laboratory of Hospital William Soler, is efficacy by diagnostic of the alterations caused by this pollen.

Lactic acid bacterial fermentation increases the antiallergic effects of Ixeris dentata

Ixeris dentata (ID, family Asteraceae), called Seumbakuy in Korea, was fermented with lactic acid bacteria (LAB) and their antiallergic activities were investigated. Fermentation of ID with Bifidobacterium breve or Lactobacillus acidophilus increased its inhibition of degranulation in RBL-2H3 cells induced by the IgE-antigen complex. Oral administration of these extracts to mice inhibited the passive cutaneous anaphylaxis (PCA) reaction induced by the IgE-antigen complex and scratching behaviors induced by compound 48/80. The fermented ID more potently inhibited the PCA reaction and scratching behaviors than the non-fermented one. These extracts also inhibited mRNA expression of TNF-alpha and IL-4, as well as NF-kappaB activation in RBL-2H3 cells induced by the IgE-antigen complex. These findings suggest that LAB fermentation improves ID-mediated inhibition of IgE-induced allergic diseases such as rhinitis and asthma, and that ID works by inhibiting degranulation and NF-kB activation in mast cells and basophils.

Anti-allergic effects of fermented Ixeris sonchifolia and its constituent in mice

To evaluate the antiallergic effect of fermented Ixeris sonchifolia (IS, family Compositae), we prepared IS Kimchi, isolated Lactic acid bacteria (LAB) from it, fermented IS with these LAB, and investigated their antiallergic effects. IS Kimchi more potently inhibited the passive cutaneous anaphylaxis (PCA) reaction induced by an IgE-antigen complex as well as the scratching behavior induced by compound 48/80 or histamine than IS. When IS was fermented with LAB isolated from IS Kimchi, its antiallergic effects was also increased. Of LAB used for fermentation, Lactobacillus brevis more potently increased the antiallergic effects. Its main constituents, chlorogenic acid and luteolin potently inhibited PCA reaction induced by IgE-antigen complex as well as pruritus induced by compound 48/80 or histamine. These constituents inhibited the expression of proinflammatory and allergic cytokines, TNF-alpha and IL-4, and transcription factor, NF-kappaB, activation induced by IgE-antigen complex in RBL-2H3 cells, as well as the degranulation of RBL-2H3 cells induced by an IgE-antigen complex. Luteolin more potently inhibited these allergic reactions than chlorogenic acid. These findings suggest that antiallergic effect of IS can be increased by LAB fermentation and fermented IS might improve allergic reactions, such as pruritus, anaphylaxis, and inflammation.

Associations among pollen sensitizations from different botanical species in patients living in the northern area of Madrid

OBJECTIVE

To determinate the existence of associations among sensitizations to antigens produced by pollen grains of different botanical species as assessed by skin prick tests in patients with respiratory disorders.

METHODS

Six hundred twenty nine consecutive patients living in the northern area of Madrid who underwent clinical evaluation because of rhinoconjunctivitis, and/or asthma were studied. All patients were tested with a skin prick test using a battery of inhalants including pollens, dust mites, molds and danders. The exploratory multivariate technique of Multiple Correspondence Analysis was used to compare the homogeneity of sensitizations between groups. Of the 629 patients, 459 (73.0%) had positive skin prick tests to pollen and were selected as the study group.

RESULTS

The most prevalent pollen sensitization was to Gramineae pollen (83.7%) followed by Oleaceae sensitisation (75.8%). Multiple Correspondence Analysis revealed the existence of an association among pollen sensitizations, showing that they clustered two groups: sensitizations to Gramineae, Oleaceae, Cupressaceae, Chenopodiaceae, Plantaginaceae (group I), and sensitizations to Betulaceae, Platanaceae, Compositae (group II). Sensitization to Parietaria was not included in any of the sensitization groups and showed an independent behaviour.

CONCLUSION

Pollen sensitizations in our area cluster into two association groups which have not previously been reported.

Susceptibility of gerbera and chrysanthemum varieties (Gerbera jamesoni and Chrysanthemum morifolium) to Fusarium oxysporum f.sp. chrysanthemi

In 2002, gerbera plants (cv Kaliki) were observed exhibiting symptoms of a wilt in a soilless cultivation at Albenga area (Northern Italy). A similar wilt was also observed in the Sanremo area (Northern Italy) on cv Red Bull, Anedin and Gud finger grown in soil. The same observations were carried out in 2004 in SW Spain where gerbera plants showing wilt symptoms were observed in soilless crops. In all cases, the planting material originated from the Netherlands. Recently on the base of experimental trials F. oxysporum f. sp. chrysanthemi was recognized as the causal agent of wilts of gerbera both in Italy and in Spain. The aim of this experimental work was the evaluation of the resistance/susceptibility of available cultivars of chrysanthemum and gerbera to the Fusarium wilt. The pathogenicity of two isolates of Fusarium chrysanthemi obtained from infected gerbera (Gerbera jamesonii) and chrysanthemum (Chrysanthemum morifolium) plants was tested on several varieties both of gerbera and chrysanthemum in 2004-2006. In 2004 and 2005 respectively 54 and 30 cultivars of chrysanthemum and 57 and 55 of gerbera were tested, while in 2006 only 53 cultivars of gerbera were tested. The results showed that respectively in 2004 and 2005 67 and 33 % of chrysanthemum cultivars were highly resistant to F. chrysanthemi obtained from chrysanthemum while 57 and 53 % were highly resistant to strain isolated from gerbera. In 2004, 2005 and 2006 47, 65 and 75 % of gerbera cultivars were highly resistant to F. chrysanthemi obtained from chrysanthemum and 48, 56 and 72 % were highly resistant to the strain isolated from gerbera.