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Isolation, Purification, and Biological Activity of a Phytotoxin Produced by Stemphylium solani

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Title: Isolation, Purification, and Biological Activity of a Phytotoxin Produced by Stemphylium solani
Author: Zheng, Lu; Lv, Rujing; Huang, Junbin; Jiang, Daohong
Abstract: Stemphylium solani, the causal agent of leaf blight of garlic (Allium sativum), produced phytotoxic metabolites in culture. A non-host-specific phytotoxin from culture filtrate of S. solani isolate DY-5, named SS-toxin, was extracted by ethyl acetate, isolated by bioassay-guided thin layer chromatography on silica gel, and purified by preparative liquid chromatography. SS-toxin produced necrotic lesions on detached garlic leaves, similar to that caused by S. solani. When wounded leaves were each treated with a 10-μl droplet of toxin, Changbanpo, a garlic cultivar susceptible to leaf blight, showed necrotic lesions at 11 μg/ml toxin, while a resistant cultivar, Qingganruanye, showed symptoms at 44 μg/ml. The effective doses causing 50% inhibition(EC50 values) of root growth and shoot elongation of the susceptible cultivar were 64.9 and 178.5 μg/ml, respectively. The SS-toxin significantly inhibited mitotic activity of root tip cells of the susceptible cultivar from 22 μg/ml and higher causing an abnormally high frequency of cells in interphase. Concentrations over 50 μg/ml of SS-toxin were found to be significantly toxic to total chlorophyll, both chlorophyll a and b, of the susceptible cultivar. The plasma membrane–cell wall interface, nuclear membranes, mitochondria, and chloroplasts were affected by SStoxin in susceptible leaf cells. This is the first report of the purification and testing of a phytotoxin produced by S. solani.
URI: http://hdl.handle.net/10214/2396
Date: 2010-10
Citation: Zheng, L., Lv, R., Huang, J., and Jiang, D. "Isolation, Purification, and Biological Activity of a Phytotoxin Produced by Stemphylium solani." Plant Disease 94 (2010): 1231-1237


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