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Abstract
SUMMARY: Phytophthora palmivora is more exacting in its nutrition for extracellular enzyme production than for growth. All of thirteen defined media tested supported fairly good growth. The major enzymes detected were: endopolygalacturonase (endo-PG), maceration factor (MF), α-L-arabinofuranosidase (AF) and phenolase. These enzymes were not detected in four of the five natural media tested. In egg-plant extract, traces of endo-PG, MF and pectin-methyl esterase were detected and higher activities of AF and phenolase produced. Inability to detect the enzymes in cultures in other plant extracts was possibly due to their inactivation by the oxidized phenols formed. The inability to detect other enzymes in cultures in defined media, especially those enzymes already implicated in plant diseases, may also be due to the fact that the media tested in the present work were not suitable for their induction. The most suitable basal medium for growth as well as good production of the major enzymes consisted of (%): 1, pectin; 2.5, glucose; 1, asparagine; 0.025, MgSO4. 7H2O; 0.5, Difco yeast-extract; traces of thiamine.
- Accepted:
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