Comportamiento del filtrado de Mycosphaerella graminicola (anamorfo Septoria tritici).
1990
Cordo C.A. | Marechal L.R. | Babinec F.J.
The objective of this work was to study the effect of Mycosphaerella graminicola filtrate upon wheat leaves and its possible usage as a resistance selection method. A liquid medium was used to culture the fungus. The culture filtrate was partially purified. Two leaf bioassays were carried out to observe reproduction of the lesion on wheat leaves. Several physical qualities of the action of the inoculum and the filtrate at cell level. Culture fiiltrate produces injuries on the leaves when injected as when topicalli applied; its effect focuses upon cell wall. A series of tests were conducted to detect activity of hydrolytic enzymes (pectolytic and cellulytic), their production by the pathogen and their effect on wheat leaf blotch. Enzymatic activity was measured by reading viscometrical reductions and by detecting free reducing groups as reaction products. Constitutive character of cellulolytic enzymes and the adaptative one of pectolytic enzymes were determined. Pathogenic action of four M. graminicola strains was correlated with the toxic action of the strains filtrate on three varieties of wheat. The 4th leaf of each variety was inoculated. Filtrate was applied onto the leaves with polyuretanic slides; they performed a wick function. Inoculum effect was measured through pycnidial coverage percent. Filtrate effect was established by a scale of necrotic injury. Statistical analysis showed that inoculation and tropical application were not correlated (r=0.192). A relationship was established between strain pathogenicity and filtrate aggressivity.
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