Induction and distribution of amylolytic activity in Cucumis Sativus L. inresponse to virus infection

Inoculation of cucumber (Cucumis sativus L. cv. Laura) cotyledons with toba cco necrosis virus (TNV) causes both qualitative and quantitative changes i n the total and fractionated protein extracts as well as in amylolytic acti vity. Using a specific test it was demonstrated that the virus infection st rongly enhances a major band (R-r 0.0645) of amylolytic activity, predomina ntly located in apoplast space. The accumulation of this extracellular amyl olytic activity is regulated by a time-dependent manner and is correlated w ith the development of necrotic lessions. The amylolytic activity may be re lated to degradation of starch shown to be accumulated in the immediate vic inity of necrotic lesions associated with the hypersensitive response (HR). The possible biological function of the identified amylolytic activity in the term of "pathosmosis" is also discussed.