A single point mutation in the novel PvCesA3 gene confers resistance to the carboxylic acid amide fungicide mandipropamid in Plasmopara viticola

The cellulose synthase 3 (CesA3) gene of oomycetes: structure, phylogeny and influence on sensitivity to carboxylic acid amide (CAA) fungicides

“…In oomycetes and plants, the machinery responsible for cellulose formation is a membrane bound enzyme complex (Paredez et al 2006;GrenvilleBriggs et al 2008) probably composed of several distinct cellulose synthase (CesA) subunits (Desprez et al 2007;Persson et al 2007). In oomycetes, up to four CesA encoding genes have been identified in Peronosporales, Pythiales and Saprolegniales (Grenville-Briggs et al 2008;Fugelstad et al 2009;Blum et al 2010b;Levesque et al 2010;Blum et al 2011); and their direct involvement in cellulose biosynthesis was demonstrated using RNA interference in P. infestans (Grenville-Briggs et al 2008). Out of the four CesAs, the CesA3 gene was most strongly expressed during mycelial growth of Phytophthora, Saprolegnia and Pythium species (GrenvilleBriggs et al 2008;Fugelstad et al 2009; indicating that it is of particular importance for the formation of cellulose in oomycetes.…”

“…Indeed, members of the carboxylic acid amides (CAAs) successfully inhibit cellulose biosynthesis in Peronosporales (Gisi et al 2012) by targeting the cellulose synthase 3 (CesA3) enzyme (Blum et al 2010a). However, single amino acid exchanges in CesA3 have been detected, conferring resistance to CAA fungicides in different plant pathogens of the Peronosporales such as P. infestans (Blum et al 2010a), Phytophthora capsici, Phytophthora melonis (Chen et al 2011), Plasmopara viticola (Blum et al 2010b), and Pseudoperonospora cubensis . In most cases, resistance was based on a single point mutation in the CesA3 gene, leading to a change at amino acid position 1105 from a conserved glycine to either alanine, serine, valine or tryptophan (G1105A, G1105S, G1105V, G1105W) (Blum et al 2010a;Blum et al 2010b;Blum et al 2011;Sierotzki et al 2011).…”

“…However, single amino acid exchanges in CesA3 have been detected, conferring resistance to CAA fungicides in different plant pathogens of the Peronosporales such as P. infestans (Blum et al 2010a), Phytophthora capsici, Phytophthora melonis (Chen et al 2011), Plasmopara viticola (Blum et al 2010b), and Pseudoperonospora cubensis . In most cases, resistance was based on a single point mutation in the CesA3 gene, leading to a change at amino acid position 1105 from a conserved glycine to either alanine, serine, valine or tryptophan (G1105A, G1105S, G1105V, G1105W) (Blum et al 2010a;Blum et al 2010b;Blum et al 2011;Sierotzki et al 2011). In artificially generated mutants of P. infestans, P. capsici and P. melonis, a change from valine to leucine or methionine at position 1109 (V1109L, V1109M) also confers resistance to CAAs (Chen et al 2011, Syngenta internal data).…”

“…In those species, little is also known about the existence of the CesA3 gene and its corresponding protein structure the configuration of which is suggested to affect sensitivity to CAAs. So far, the CesA3 gene has been described only in few oomycetes belonging to the Peronosporales, Pythiales and Saprolegniales (Grenville-Briggs et al 2008;Fugelstad et al 2009;Blum et al 2010b;Levesque et al 2010;Blum et al 2011), thus, the present study aimed to isolate and characterize the CesA3 gene in species from all six "crown" oomycete orders (Beakes & Sekimoto 2009). We identified the CesA3 gene in 14 different species of 11 genera, belonging to the six orders Albuginales, Leptomitales, Peronosporales, Pythiales, Rhipidiales and Saprolegniales.…”

EMS and UV irradiation induce unstable resistance against CAA fungicides in Bremia lactucae

“…No mutation was found at position 1105 that was shown to affect sensitivity to CAAs in Plasmopara viticola (Blum et al 2010a) All isolates displayed Gly1105 encoded by codon GGC (as exemplified in Fig. 7b).…”