Authors:T. Janda, M. Cséplő, Cs. Németh, Gy. Vida, M. Pogány, G. Szalai and O. Veisz
Treatment with various concentrations (0, 5, 15 and 20%) of PEG was used to simulate water stress, followed by inoculation with
(DTR) at two different points of time (6 and 72 h after the PEG treatment) in two DTR resistant (M-3 and Mv Magvas) and two sensitive (Bezostaya 1 and Glenlea) wheat varieties. The reduction in biomass production due to the PEG treatments was more pronounced in the shoots than in the roots. While in the case of Bezostaya 1 5% PEG reduced the level of infection, 20% PEG treatment lowered the tolerance level of M-3. DTR infection may be more efficient in inducing antioxidative defence systems than water stress. However, there was no direct correlation between the activity of the individual antioxidant enzymes and the drought or DTR tolerance of wheat plants.
Authors:J. Hamar, M. Solymár, E. Tanai, P. Cseplo, Zs. Springo, G. Berta, B. Debreceni and Akos Koller
Recent studies suggest that hydrogen sulfide (H2S) exhibits potent antioxidant capacity and improves vascular and tissue functions. Thus we aimed to compare the antioxidant efficacy of H2S to that of superoxide dismutase (SOD).Isometric force of isolated rat carotid arteries and gracilis veins was measured with a myograph. The vasomotor effect of the superoxide-generator pyrogallol (10−5M) was obtained in control conditions, and then in the presence of SOD (120 U/ml) or H2S (10−5M or 10−4M), respectively. Spectrophotometric measurements were performed to detect the effect of SOD and H2S on the auto-oxidation of pyrogallol.Pyrogallol increased the isometric force of carotid arteries (9.7 ± 0.8 mN), which was abolished by SOD (5.3 ± 0.8 mN), was not affected by 10−5M H2S (9.1 ± 0.5 mN), whereas 10−4M H2S slightly, but significantly reduced it (8.1 ± 0.7 mN). Pyrogallol significantly increased the isometric force of gracilis veins (1.3 ± 0.2 mN), which was abolished by SOD (0.9 ± 0.2 mN), whereas 10−5M (1.3 ± 0.2 mN), or 10−4M H2S (1.2 ± 0.2 mN) did not affect it. Pyrogallol-induced superoxide production was measured by a spectrophotometer (A420 = 0.19 ± 0.0). SOD reduced absorbance (A420 = 0.02 ± 0.0), whereas 10−5M H2S did not (A420 = 0.18 ± 0.0) and 10−4M H2S slightly reduced it (A420 = 0.15 ± 0.0).These data suggest that H2S is a less effective vascular antioxidant than SOD. We propose that the previously described beneficial effects of H2S are unlikely to be related to its direct effect on superoxide.
Authors:G. Vida, M. Cséplő, G. Gulyás, I. Karsai, T. Kiss, J. Komáromi, E. László, K. Puskás, Z. Wang, C. Pace, Z. Bedő, L. Láng and O. Veisz
Among the factors which determine yield reliability an important role is played by disease resistance. One of the breeding aims in the Martonvásár institute is to develop wheat varieties with resistance to major diseases. The winter wheat varieties bred in Martonvásár are examined in artificially inoculated nurseries and greenhouses for resistance to economically important pathogens. The effectiveness of designated genes for resistance to powdery mildew and leaf rust has been monitored over a period of several decades. None of the designated major resistance genes examined in greenhouse tests is able to provide complete resistance to powdery mildew; however, a number of leaf rust resistance genes provide full protection against pathogen attack (Lr9, Lr19, Lr24, Lr25, Lr28 and Lr35). In the course of marker-assisted selection, efficient resistance genes (Lr9, Lr24, Lr25 and Lr29) have been incorporated into Martonvásár wheat varieties. The presence of Lr1, Lr10, Lr26, Lr34 and Lr37 in the Martonvásár gene pool was identified using molecular markers. New sources carrying alien genetic material have been tested for powdery mildew and leaf rust resistance. Valuable Fusarium head blight resistance sources have been identified in populations of old Hungarian wheat varieties. Species causing leaf spots (Pyrenophora tritici-repentis, Septoria tritici and Stagonospora nodorum) have gradually become more frequent over the last two decades. Tests on the resistance of the host plant were begun in Martonvásár four years ago and regular greenhouse tests on seedlings have also been initiated.