Spontaneous and CRISPR/Cas9-induced mutation of the osmosensor histidine kinase of the canola pathogen Leptosphaeria maculans

• Published in: Fungal biology and biotechnology Vol. 4; no. 1; p. 12
• Main Authors: Idnurm, Alexander, Urquhart, Andrew S, Vummadi, Dinesh R, Chang, Steven, Van de Wouw, Angela P, López-Ruiz, Francisco J
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 16-12-2017; BioMed Central; BMC
• Subjects: Agrobacterium-mediated transformation; Canola; Gene editing; Gene mutation; Genetic aspects; Genetic research; Histidine; HOG pathway; HOG pathway; Canola; Agrobacterium-mediated transformation; Gene editing
• ISSN: 2054-3085; 2054-3085
• DOI: 10.1186/s40694-017-0043-0

The dicarboximide fungicide iprodione has been used to combat blackleg disease of canola (
), caused by the fungus
. For example, in Australia the fungicide was used in the late 1990s but is no longer registered for use against blackleg disease, and therefore the impact of iprodione on
has not been investigated.
Resistance to iprodione emerged spontaneously under in vitro conditions at high frequency. A basis for this resistance was mutations in the
gene that encodes a predicted osmosensing histidine kinase. While loss of the homologous histidine kinase in some fungi has deleterious effects on growth and pathogenicity, the
strains with the
gene mutated had reduced growth under high salt conditions, but were still capable of causing lesions on
. The relative ease to isolate mutants with resistance to iprodione provided a method to develop and then optimize a CRISPR/Cas9 system for gene disruptions in
, a species that until now has been particularly difficult to manipulate by targeted gene disruptions.
While iprodione is initially effective against
in vitro, resistance emerges easily and these strains are able to cause lesions on canola. This may explain the limited efficacy of iprodione in field conditions. Iprodione resistance, such as through mutations of genes like
, provides an effective direction for the optimization of gene disruption techniques.