-Glucosidase in Heterodera Rostochiensis and Its Significance in Resistance of Potato To This Nematode

Author: Wilski A.   Giebel J.  

Publisher: Brill

ISSN: 1875-2926

Source: Nematologica, Vol.12, Iss.2, 1966-01, pp. : 219-224

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Abstract

-glucosidase was found in Heterodera rostochiensis larvae. Two biotypes were tested in vitro, biotype A (which does not break resistance in crosses of Solanum andigenum) and biotype B (which breaks resistance in S. andigenum). The enzyme activity in biotype A was several times greater than in biotype B. The pH of the environment greatly influenced the level of enzyme activity. At pH 6.5 - that of potato root cell contents - traces of enzyme activity were detected in larvae of biotype B, while biotype A showed appreciable amounts. The hypothesis is proposed that potato resistance to H. rostochiensis is dependent on the presence of phenolic glucosides in the root cells of resistant potatoes which are hydrolized by -glucosidase secreted by the larvae. As a result free polyphenols are released which cause necrosis. The activity of -glucosidase secreted by larvae of biotype B apparently is too low to hydrolize the glucosides and therefore necroses are not formed.