Youssef,, S., Tartoura, K., Vargas Jr, J. (2003). ANTAGONISTIC INTERACTIONS BETWEEN THE BACTERIAL ANTAGONIST Pseudomonas fluorescens Q2· 87 AND PATHOGENIC Pytbium SPP. IN RELATION rO HYPHAL ULTRASTRUCTURAL ANALYSIS. Journal of Plant Protection and Pathology, 28(12), 8419-8436. doi: 10.21608/jppp.2003.247787
S. A. Youssef,; K. A. H. Tartoura; J. M. Vargas Jr. "ANTAGONISTIC INTERACTIONS BETWEEN THE BACTERIAL ANTAGONIST Pseudomonas fluorescens Q2· 87 AND PATHOGENIC Pytbium SPP. IN RELATION rO HYPHAL ULTRASTRUCTURAL ANALYSIS". Journal of Plant Protection and Pathology, 28, 12, 2003, 8419-8436. doi: 10.21608/jppp.2003.247787
Youssef,, S., Tartoura, K., Vargas Jr, J. (2003). 'ANTAGONISTIC INTERACTIONS BETWEEN THE BACTERIAL ANTAGONIST Pseudomonas fluorescens Q2· 87 AND PATHOGENIC Pytbium SPP. IN RELATION rO HYPHAL ULTRASTRUCTURAL ANALYSIS', Journal of Plant Protection and Pathology, 28(12), pp. 8419-8436. doi: 10.21608/jppp.2003.247787
Youssef,, S., Tartoura, K., Vargas Jr, J. ANTAGONISTIC INTERACTIONS BETWEEN THE BACTERIAL ANTAGONIST Pseudomonas fluorescens Q2· 87 AND PATHOGENIC Pytbium SPP. IN RELATION rO HYPHAL ULTRASTRUCTURAL ANALYSIS. Journal of Plant Protection and Pathology, 2003; 28(12): 8419-8436. doi: 10.21608/jppp.2003.247787
ANTAGONISTIC INTERACTIONS BETWEEN THE BACTERIAL ANTAGONIST Pseudomonas fluorescens Q2· 87 AND PATHOGENIC Pytbium SPP. IN RELATION rO HYPHAL ULTRASTRUCTURAL ANALYSIS
1Department of Agricultural Botany, Suez-Canal University, Isma ilia, Egypt
2Department of Plant Pathology, Michigan State University, East Lansing, Mil USA 48824
Abstract
Effects of the biocontrol agent Pseudomonas fJuofescens Q2·87 that is known to produce the antibiotic 2.4-diacetylphloroglucinol (2.4-DAPG) on phytopathogenic Pythium spp, In relation to electron microscopic analysis of t~e hyphal cen walls were Investigated, The outcome of the antagonistic Interactlcos between this strain and Pythium spp .. by means of light and scanning electron microscope, when co-cultivated on potato dextrose agar was described. Lig~t micrographs are presented that displayed hyphal distortion. swollen shapes and unusual apical branching. In addition, scanning electron micrographs are also presented that dIsplayed degradation of the cell wall layers and revealed the cellulosic wall microfibrillar skeleton. A similar cell wall degradation was observed when POt medium was emended with the synthetic antibiotic 2,4·DAPGflhus. It might b~ concluded that the natural antibiotic 2,4-DAPG i!t primarily respo~ib\e for antagonistic process of the Oomycete P. ultimum induced by P. fJuorescens 02·87. Our results based on ultrastructural observations provide evidence that the modes of this strair1 action in Inhibition. preventing colonization by Pythium are mainly associated with major cell wall degradation, and eventually death of Pythium cells, as a result of extensive celf wall breakdown.
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