Open AccessFungal Colonization and Host Defense Reactions in Ulmus americana Callus Cultures Inoculated with Ophiostoma novo-ulmi
Author(s) -
Mirella Aoun,
Danny Rioux,
Marie Simard,
Louis Bernier
Publication year - 2009
Publication title -
phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.264
H-Index - 131
eISSN - 1943-7684
pISSN - 0031-949X
DOI - 10.1094/phyto-99-6-0642
Subject(s) - biology , ophiostoma , colonization , inoculation , dutch elm disease , host (biology) , ceratocystis , callus , botany , ulmaceae , fungi imperfecti , defence mechanisms , microbiology and biotechnology , genetics , fungus , horticulture , gene
The host–pathogen interaction leading to Dutch elm disease was analyzed using histo- and cyto-chemical tests in an in vitro system. Friable and hard susceptible Ulmus americana callus cultures were inoculated with the highly aggressive pathogen Ophiostoma novo-ulmi. Inoculated callus tissues were compared with water-treated callus tissues and studied with light microscopy (LM), transmission-electron microscopy (TEM), and scanning-electron microscopy (SEM). New aspects of this interaction are described. These include the histological observation, for the first time in plant callus cultures, of suberin with its typical lamellar structure in TEM and the intracellular presence of O. novo-ulmi. Expression of the phenylalanine ammonia lyase gene, monitored by real-time quantitative polymerase chain reaction, was correlated with the accumulation of suberin, phenols, and lignin in infected callus cultures. This study validates the potential use of the in vitro system for genomic analyses aimed at identifying genes expressed during the interaction in the Dutch elm disease pathosystem.