QTL mapping of slow-rusting, adult plant resistance to race Ug99 of stem rust fungus in PBW343/Muu RIL population.

Races of stem rust fungus pose a major threat to wheat production worldwide. We mapped adult plant resistance (APR) to Ug99 in 141 lines of a PBW343/Muu recombinant inbred lines (RILs) population by phenotyping them for three seasons at Njoro, Kenya in field trials and genotyping them with Diversity Arrays Technology (DArT) markers. Moderately susceptible parent PBW343 and APR parent Muu displayed mean stem rust severities of 66.6 and 5 %, respectively. The mean disease severity of RILs ranged from 1 to 100 %, with an average of 23.3 %. Variance components for stem rust severity were highly significant (p < 0.001) for RILs and seasons and the heritability (h (2)) for the disease ranged between 0.78 and 0.89. Quantitative trait loci (QTL) analysis identified four consistent genomic regions on chromosomes 2BS, 3BS, 5BL, and 7AS; three contributed by Muu (QSr.cim-2BS, QSr.cim-3BS and QSr.cim-7AS) and one (QSr.cim-5BL) derived from PBW343. RILs with flanking markers for these QTLs had significantly lower severities than those lacking the markers, and combinations of QTLs had an additive effect, significantly enhancing APR. The QTL identified on chromosome 3BS mapped to the matching region as the known APR gene Sr2. Four additional QTLs on chromosomes 1D, 3A, 4B, and 6A reduced disease severity significantly at least once in three seasons. Our results show a complex nature of APR to stem rust where Sr2 and other minor slow rusting resistance genes can confer a higher level of resistance when present together.

Sensitization to airborne ascospores, basidiospores, and fungal fragments in allergic rhinitis and asthmatic subjects in San Juan, Puerto Rico.

BACKGROUND: Fungal spores are the predominant biological particulate in the atmosphere of Puerto Rico, yet their potential as allergens has not been studied in subjects with respiratory allergies. The purpose of this study was to determine the level of sensitization of subjects with respiratory allergies to these particles. METHODS: Serum samples were drawn from 33 subjects with asthma, allergic rhinitis, or nonallergic rhinitis and 2 controls with different skin prick test reactivity. An MK-3 sampler was used to collect air samples and the reactivity of the sera to fungal particles was detected with a halogen immunoassay. RESULTS: All subjects reacted to at least 1 fungal particle. Thirty-one subjects reacted to ascospores, 29 to basidiospores, 19 to hyphae/fungal fragments, and 12 to mitospores. The median percentage of haloes in allergic rhinitis subjects was 4.82% while asthma or nonallergic rhinitis subjects had values of 1.09 and 0.39%, respectively. Subjects with skin prick tests positive to 3, 2, 1, or no extract had 5.24, 1.09, 1.61, and, 0.57% of haloed particles, respectively. If skin prick tests were positive to basidiomycetes, pollen, animals, or deuteromycetes, the percentages of haloes were 4.72, 4.15, 3.63, and 3.31%, respectively. Of all haloed particles, 46% were unidentified, 25% ascospores, 20% basidiospores, 7% hyphae/fungal fragments, and 2% mitospores. IgE levels and the number of positive skin prick test extracts correlated with the percentage of haloes. CONCLUSION: In tropical environments, sensitization to airborne basidiomycetes, ascomycetes, and fungal fragments seems to be more prevalent than sensitization to mitospores in subjects with active allergies, suggesting a possible role in exacerbations of respiratory allergies.

Glucans from the Caripia montagnei mushroom present anti-inflammatory activity.

Caripia montagnei is a basidiomycete species which contains polysaccharides with immunomodulatory properties. An extract of this mushroom underwent removal of the fat content by organic solvent and subsequently proteolysis. The aqueous phase obtained after proteolysis was precipitated with methanol yielding a fraction containing carbohydrates (98.7+/-3.3%) and protein (1.3+/-0.25%). Chemical analysis, infrared spectroscopy and nuclear magnetic resonance (NMR) showed that the carbohydrate fraction contained (63.3+/-4.1) of beta-glucans and proteins (2.2+/-0.3%). These glucans (50mg/kg of body weight) significantly reduced the inflammatory infiltrate produced by thioglycolate-induced peritonitis by 75.5+/-5.2%, when compared to Wy-14643 (60.3+/-6.1%), PFOA (37.8+/-2.8%) and clofibrate (52.2+/-3.2%), p<0.001, which are of the peroxisome proliferator-activated receptor (PPAR-alpha). L-NAME, a nitric oxide synthase inhibitor, reduced the plantar edema in Wistar rats by 91.4+/-1.3% (p<0.001). A significant reduction in nitric oxide (NO) levels was observed in the exudates when the glucans was used in comparison to carrageenan. The C. montagnei glucans did not present signs of inducing cytotoxicity. A decrease in IL-1ra, IL-10 and IFN-gamma in the peritonitis model was observed. Thus, the results suggest that glucans from the C. montagnei mushroom is an effective immunomodulator and may have potential for anti-inflammatory properties.

Antineoplasic activity of Agaricus brasiliensis basidiocarps on different maturation phases

The fungus Agaricus brasiliensis is a Basidiomycete studied because of its immunomodulation and/or antitumor substances. The objective of this study was to verify the Agaricus brasiliensis antineoplasic activity in vivo on different basidiocarp maturation phases on Sarcoma 180 cells implanted in mice. Sarcoma cells were implanted in mice and after seven days mice were divided in three groups. The first group was treated with saline solution, the second group was treated with closed basidiocarp extract solution and the third group was treated with opened basidiocarp extract solution. After 30 days of being daily orally treated with these three solutions all animals suffered euthanasia, and the splenic index, tumor mass and volume were determined. No significant differences of the tumor growth inhibition in function of the different basidiocarp maturation phases for the Agaricus brasiliensis strain were observed. The in vivo basidiocarp antineoplasic average activity was 89.22 percent.

Surface plasmon resonance immunosensor for early diagnosis of Asian rust on soybean leaves.

Soybean rust (Asian rust) is a disease that occurs in soy cultures, negatively affecting pod formation and final grain weight and reducing value and product quality. Early identification of fungus in the plants prevents severe farming losses and spread to neighboring cultures. In this paper, a fast response sensor was developed based on surface plasmon resonance to detect Asian rust in soybean leaf extract at early stages of the disease. The antibody anti-Phakopsora pachyrhizi (pathogen) was covalently immobilized on a gold substrate via a self-assembled monolayer (SAM) of thiols using cysteamine-coupling chemistry. This immunosensor presented a linear response range for the antigen from 3.5 to 28.0 microg mL(-1) (r(2)=0.996). The effects of the antibody amount and the surface blocking to minimize non-specific adsorption on immunosensor response were evaluated. These studies provide new perspectives on using SPR technology for the development of a highly sensitive sensor for agricultural applications.

Sensitization to the fungus Hemileia vastatrix (coffee leaf rust).

BACKGROUND: The aim of the present study was to determine the existence of sensitization to the fungus Hemileia vastatrix (coffee leaf rust) in a sample of the Brazilian population. This fungus attacks coffee plantations, and in some regions of Brazil the concentration of its spores in the air can be very high. METHODS: A total of 378 individuals underwent skin tests (prick and intradermal tests) with H. vastatrix extract. The subjects were divided into four groups according to the occurrence of atopy and the region where they lived (coffee-growing or non-coffee-growing regions), and another group (V) consisted of 50 rural workers employed on coffee plantations. The presence of specific IgE against the fungus H. vastatrix in sensitized individuals was demonstrated in vitro by immunoblotting. RESULTS: There was no statistical difference in comparing the results with intradermal or prick tests. The incidence of positive tests was significantly higher among atopic individuals residing in coffee-growing regions (14.7%). Among rural workers, 10% showed positive tests. Immunoblotting revealed specific IgE against 20 protein bands of H. vastatrix. CONCLUSION: The fungus H. vastatrix may be an important allergen in coffee-producing countries. The sensitization is more frequent among atopic individuals residing in coffee-growing regions.

Evaluation of the allergenicity of spore and mycelia extracts of Pisolithus tinctorius.

The antigenic and allergenic chemical analysis of spore and mycelia extracts of Pisolithus tinctorius was carried out. The spores were collected from basidiocarps in plantations of Eucalyptus spp and the mycelia from culture in MNM medium. With basis on the fungus growth curve, the mycelia masses were obtained after 10, 20, 30, and 40 days of incubation, which correspond, respectively, to the beginning, middle and end of the log phase, and beginning of the decline phase. The mycelia masses, together with the spores, were submitted to the action of three extractors (Coca, Tris-HCl, and ammonium bicarbonate). The contents of carbohydrates and proteins were determined. The SDS-PAGE electrophoretical analysis revealed separate fractions in these extracts, besides common fractions, in function of cultivation time and extraction methods. The selected extracts for the allergic tests were the ones with the highest number of fractions. The prick-tests were conducted in 374 patients--rural workers, eucalyptus plantation workers, and college students. The positivity to the "prick test" with the antigenic extract of P. tinctorius was, respectively, 3.78%, 28.20% and 6.40%. Most prick-test positive patients (82.75%) also presented symptoms of respiratory allergy (asthma and rhinitis). There was no reactivity difference when the spore and mycelia extracts were employed. The analysis of the positive patients' sera revealed the presence of IgE specific to the P. tinctorius antigens. Since Pisolithus tinctorius is found as mycorrhiza of Eucalyptus spp, and this plant is used in reforestation in most countries, the importance of that fungus should be regarded as a possible cause of respiratory allergies, especially in occupationally exposed workers.

[Preliminary serological study of fungus cultivated by the manioc ant Acromyrmex octospinosus Reich in Guadeloupe]. / Etude sérologique préliminaire du champignon cultivé par la fourmi-manioc acromyrmex octospinosus Reich en Guadeloupe.

The serologic study of four strains of fungus cultivated by Acromyrmex octospinosus (Reich) in Guadeloupe has revealed four major antigens common to all four strains. Two additional weaker antigens were present in some but not all strains, which may indicate quantitative differences in viral particles in the hyphae of the fungi. The use of serological techniques should facilitate taxonomic study of the fungi (and possibly the virus or viruses which parasitize the fungi) cultivated by different species of Attine ants.