Phytoparasitica (2000) 28, p. 278 (Bakshi et al.)

S. Bakshi, O. Yarden and A. Sztejnberg (2000)
Glucanase activity and genetic transformation of Fusarium proliferatum, a biocontrol agent of grape downy mildew
Phytoparasitica 28 (3), 278-278
21st Congress of the Israeli Phytopathological Society, February 14-15, 2000, Bet Dagan, Israel, lecture
Abstract: The Fusarium proliferatum G6 isolate shows antagonistic traits against fungi belonging to the Oomycotina, and among them Plasmopara viticola, the causal agent of grape downy mildew. At temperatures lower than 18°C (which are favorable for growth of P. viticola) there is a negative correlation between the temperature and growth capacity and antagonism of the G6 isolate. Following the exposure of F. proliferatum G6 microconidia to UV radiation, and screening for growth at low temperatures, an isolate (designated 1505) that excelled in linear growth rate at low temperatures (13-18°C) was obtained. In a pathogenesis test performed at temperatures ranging from 13 to 25°C, we found that isolate 1505 significantly lowered the number of sporangia that were released from P. viticola in comparison with the effect of the original isolate (G6). We determined the activity and abundance of extracellular lytic enzymes of isolates G6 and 1505. The isolates were grown in liquid media and glucanase enzyme activity secreted to the medium was analyzed with different substrates. The activity of extracellular exo-ß-1,4-glucanase and carboxymethylcellulase (CMCase) was significantly higher in isolate 1505 than in isolate G6. The presence of extracellular enzymes is in agreement with the assumption that lytic enzymes are involved in mycoparasitism. There is a possibility that the high activity of these enzymes in isolate 1505 may be related to the higher antagonistic activity of this isolate compared with isolate G6. In the course of this study we modified a protoplast-based method for DNA-mediated transformation of F. proliferatum. Resistance to an antibiotic (hygromycin B) was conferred to the fungus and a reporter gene (GUS) was successfully integrated into the fungal genome. We intend to take advantage of transformed isolates for the analysis of mycoparasite-pathogen-plant interactions.

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plasmopara viticola	Grapevine (Vitis)
Fusarium proliferatum (antagonist)	Plasmopara viticola	Grapevine (Vitis)