Chemistry of Hyphal Walls of Phytophthora

Abstract

Hyphal walls of two phytopathogenic moulds, Phytophthora cinnamomi and P. parasitica, were isolated essentially free from cytoplasmic contamination. They have a complex chemical structure consisting of polysaccharide, protein and lipid. D- Glucose was the main monosaccharide detected in acid hydrolysates. Chromatographic evidence suggested the presence of small amounts of mannose (0.6%), glucosamine (0.3%) and traces of galactosamine and ribose. Glucans constituted nearly 90% of the wall but only about a maximum 25% of the wall could be regarded as cellulsoe I on the basis of solubility, resistance to hydrolysis and X-ray diffraction. Most of the wall glucan exhibited chemical and physical properties unlike typical cellulose. The spectrum of amino acids commonly found in fungal walls was detected; hydrolysates also con-tained hydroxyproline and two minor unidentified ninhydrin-positive components. Protein comprise 3-5% of the wall. A small amount of lipid (1-3%), mostly of the bound type, was found, and also traces of phosphorus, and compounds with absorption maxima at 263m[mu]. Hyphal walls of Phytophthora cinnamomi and P. paras itica differed only slightly in quantitative composition.