Historical perspectives of white rust caused by Albugo candida in Oilseed Brassica

Abstract

Albugo candida (Pers. Ex. Lev.) Kuntze is a wide spread pathogen of cruciferous crops causing heavy
yield losses all over the world. Molecular and phylogenetic studies of the family Albuginaceae
revealed four distinct lineages: Albugo s.str., Albugo s.l., Pustula s.l. and Wilsoniana s.l. It’s host range is
more than 300 hosts. The host specificity of A. candida has been recorded from more than eight countries of
the world. Studies on host-pathogen interaction, fine structures of hyphae, mycelium, haustoria, sporangia,
zoospores and oospores have been conducted through histopathology, electron microscopy, scanning electron
microscopy and transmission electron microcopy. The pathogen survives through mycelium, sporangia and
oospores. Germination of sporangia and oospores has been determined. Biochemical host-pathogen
interaction studies have been conducted. Studies on identification and cloning of plant defense resistance
genes are in progress. Genome sequencing of A. candida and A. laibachii have been made. Very useful and
reproducible techniques have been developed on the aspects viz., growth chamber inoculation, oospore
germination, induction of stag-heads, detached leaf culture, In vitro callus culture, temperature effects on
disease development and oospore formation, process of infection, association of white rust and downy
mildew, pathogenic variability, virulence spectrum, host resistance, genetic of host-parasite interaction, slow
white rusting and chemical control. Future research areas have been suggested.