疫病菌の軟化酵素について : 1. Phytophthora capsiciの分泌する軟化酵素の特性

概要

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Phytophthora capsici caused a soft rot of cucumber fruits and produced a number of pectic enzymes in the macerated tissues. Both cell-free extracts of macerated tissues and fungus culture fluids effectively macerated potato tuber and cucumber fruit sections at pH optima of 6.2 and 7.0, respectively. P. capsici produced two enzymes it culture which preferentially degraded pectic acid (pH optima of 5.0 and 6.2) and four which attacked pectin (pH optima of 3.5, 5.5, 6.5, and above 7.0). The activity for pectin above pH 7 appeared due endo-pectin methyl-trans-eliminase (end-PMTE) based on the thio-barbituric acid test. The culture filtrates also contained one exo-type activity for pectic acid with a pH optimum at 5.5, but almost no pectin methylesterase and cellulase (Cx) activities. The extracts from infected cucumber fruit, however, showed only one endo-pectolytic activity for pectic acid with a pH optimum at 6.2 and two endo-type activities for pectin with pH optima at 6.5 and above 7.0. The latter activity appeared due to endo-PMTE activity. The data show that P. capsici produces an endo-polygalacturonase and an endo-PMTE which could be responsible for soft rot development in rot development in cucumber fruit.
日本植物病理学会の論文
1973-12-25