Characteristics of fluopicolide-resistance mutants in Phytophthora nicotianae, the pathogen causing black shank disease in tobacco.
Pestic Biochem Physiol
; 201: 105876, 2024 May.
Article
in En
| MEDLINE
| ID: mdl-38685244
ABSTRACT
Black shank, a devastating disease in tobacco production worldwide, is caused by the oomycete plant pathogen Phytophthora nicotianae. Fluopicolide is a pyridinylmethyl-benzamides fungicide with a unique mechanism of action and has been widely used for controlling a variety of oomycetes such as Plasmopara viticola, Phytophthora infestans, Pseudoperonospora cubensis, P. nicotianae and Bremia lactucae. However, the fluopicolide-resistance risk and molecular basis in P. nicotianae have not been reported. In this study, the sensitivity profile of 141 P. nicotianae strains to fluopicolide was determined, with a mean median effective concentration (EC50) value of 0.12 ± 0.06µg/mL. Five stable fluopicolide-resistant mutants of P. nicotianae were obtained by fungicide adaptation, and the compound fitness index of these resistant mutants were lower than that of their parental isolates. Additionally, cross-resistance tests indicated that the sensitivity of fluopicolide did not correlate with other oomycete fungicides, apart from fluopimomide. DNA sequencing revealed two point mutations, G765E and N769Y, in the PpVHA-a protein in the fluopicolide-resistant mutants. Transformation and expression of PpVHA-a genes carrying G765E and N769Y in the sensitive wild-type isolate confirmed that it was responsible for fluopicolide resistance. These results suggest that P. nicotianae has a low to medium resistance risk to fluopicolide in laboratory and that point mutations, G765E and N769Y, in PpVHA-a are associated with the observed fluopicolide resistance.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phytophthora
/
Plant Diseases
/
Nicotiana
/
Fungicides, Industrial
/
Mutation
Language:
En
Journal:
Pestic Biochem Physiol
/
Pestic. biochem. physiol
/
Pesticide biochemistry and physiology
Year:
2024
Type:
Article
Affiliation country:
China