Premium
Biology of the Gaeumannomyces graminis Arx & Olivier/ Phialophora radicicola Cain Complex on Roots of the Gramineae
Author(s) -
Deacon J.W.
Publication year - 1976
Publication title -
eppo bulletin
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.327
H-Index - 36
eISSN - 1365-2338
pISSN - 0250-8052
DOI - 10.1111/j.1365-2338.1976.tb02033.x
Subject(s) - conidium , biology , botany , agar , agar plate , graminicola , fungus , pathogenicity , microbiology and biotechnology , bacteria , genetics , pathogen
Biological characteristics of the varieties of Gaeumannomyces graminis Arx & Olivier and Phialophora radicicola Cain are reviewed. They include: 1) pathogenicity to roots of cereals; 2) growth on living stem tissues; 3) type of fungal growth‐cessation structure formed on or in the host. Together, these provide a simple means of characterizing isolates and standard methods for assessing them are presented. The role of pigmented cells and tissues (growth‐cessation structures) in host penetration is questioned, since they are seldom associated with a progressive infection by G. graminis or P. radicicola . However, they are a taxonomic aid, especially as they are now known to form on cellophane overlying agar. New evidence is presented on factors affecting conidiation by these fungi. Flooding colonies with distilled water induced formation of conidia by G. graminis var. tritici Walker, P. radicicola var. radicicola (British isolates but not the type) and P. radicicola var. graminicola Deacon, whereas none formed on corresponding unflooded agar plates. Conidia were usually much larger and germinated readily when they formed in response to flooding; many of these fungi therefore have 2 conidial types, distinct in both morphology and behaviour. Preliminary results suggest that biotin and the form of nitrogen also affect the type of conidium formed by P. radicicola var. radicicola .