Authors:V. Pós, É. Hunyadi-Gulyás, R. Caiazzo, I. Jócsák, K. Medzihradszky, and N. Lukács
The effect of cadmium on protein expression in the aerial parts of barley (Hordeum vulgare L. cv. ‘Mandolina’) seedlings was investigated by proteomic analysis of leaf apoplast proteins. Dramatic changes were observed in the protein pattern of intercellular washing fluid from Cd-treated (0–300 μM) barley leaves both by 1D- and 2D-PAGE. By mass spectrometric (MALDI-TOF and/or LC-MS/MS) analysis of induced proteins PR1 proteins, certain 1-3-glucanases (PR2), chitinases (PR3), members of the chitin binding PR4 family, a rich set of thaumatin-like proteins (PR5) and two PR17 proteins were identified, indicating that a general plant defence response, inducing massive secretion of pathogenesis-related proteins (PR) into the extracellular space, is an important part of the Cd-induced stress reactions. Although systemic induction of PR proteins is probably important for an adequate plant response to cadmium stress, many of these proteins are known to have an allergenic potential and as such present a health risk to plant eaters, even when the heavy metal concentration in the given plant organ is low.
Authors:K. Halász, A. Geösel, J. Szarvas, N. Virágh, Cs. Hajdú, and N. Lukács
Mycoviruses are known to infect fungi of different habitats and life style. Some of them, like the Mushroom Virus X (MVX) complex, cause abnormal development of fruiting bodies and severe yield losses in mushroom cultivation. Most mycoviruses have a double-stranded RNA (dsRNA) genome, therefore dsRNA-detection is frequently used as a first step to identify virus infection. In relation with MVX 23 dsRNAs species have been described, occurring in variable number and combination in diseased mushrooms. The aim of our experiments was to find out whether dsRNA-immunoblotting can be used to detect dsRNA in small samples of cultivated A. bisporus varieties and of wild growing Agaricus species. We found that by immunoblotting, the same dsRNA species were detected in apparently healthy cultivated champignon fruiting bodies and in MVX-infected reference samples, respectively, as by conventional CF11 chromatography, but for immunoblotting a much smaller sample size was needed. In two out of three deformed fruit bodies of cultivated A. bisporus from Hungary we detected a 4.1 kbp dsRNA species which was also present in the MVX infected reference samples. Diverse and variable dsRNA patterns were observed in apparently healthy samples of 12 wild growing Agaricus species, indicating that extreme care should be taken when non-cultivated Agaricus is used for breeding new varieties. Non-sterile cultures and environmental mushroom specimens are fairly often mixed with parasitic and endofungal organisms, therefore, we also tested fungi isolated from mushroom cultures. Here again, 1–7 dsRNA species were found in extracts of Trichoderma and Dactylium isolates and of Mycogone-infected sporophores. Our results demonstrate clearly that dsRNAs from very different origins can be present in cultivated champignon and support the view that the MVX symptom-associated dsRNAs are probably of polyphyletic origin and do not represent one defined virus.