Abstract: Verticillium dahliae Kleb. is a phytopathogenic fungus that causes cotton wilt-disease. Glycoproteins secreted by V. dahliae have been found to play an important role in wilting syndrome. In this study the glycoproteins were purified consecutively by ConA-Sepharose 4B affinity chromatography, Sephadex G-150 gel filtration, two-dimensional gel electrophoresis and SDS gradient gel electrophoresis. The N-terminal residual sequence of a 26 kD glycoprotein was analyzed. Plant-wilting tests were carried out by injection of glycoproteins, and those treated by heat, ConA and zeatin, into cotton leaves, respectively. Results showed that heat and ConA treatment abolished the wilt-causing activity of the glycoproteins, and zeatin alleviated the wilt syndrome of cotton. Furthermore, the glycoproteins were found to be effective elicitors in inducing the biosynthesis of sesquiterpene aldehyde phytoalexins in suspension cell cultures of Gossypium barbadense L., and heat-treatment lowered, but not abolished the elicitor activity. However, application of native glycoproteins at the concentration higher than 5 mg/L resulted in cell death.

Key words: Gossypium barbadease , Verticillium dahliae , Wilt, Glycoproteins