Premium
Three point‐mutations in cytochrome b confer resistance to trifloxystrobin in Magnaporthe oryzae
Author(s) -
Miao Jianqiang,
Zhao Guosen,
Wang Bin,
Du Yixin,
Li Zhiwen,
Gao Xuheng,
Zhang Can,
Liu Xili
Publication year - 2020
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.5990
Subject(s) - mutant , magnaporthe , biology , carbendazim , point mutation , azoxystrobin , microbiology and biotechnology , genetics , gene , oryza sativa , fungicide , botany , magnaporthe grisea
BACKGROUND Rice blast, caused by Magnaporthe oryzae , is the most devastating disease in rice. Recently, trifloxystrobin was registered for the control of M. oryzae in China. The resistance profile and mechanism of M. oryzae to trifloxystrobin were investigated in the present study, providing important data for the recommended use of trifloxystrobin. RESULTS The baseline sensitivity was established at a half maximal effective concentration (EC 50 ) of 0.024 μg mL −1 . Nine stable trifloxystrobin‐resistant mutants were generated with EC 50 values ranging from 12.75 to 171.49 μg mL −1 . The mutants exhibited strong adaptive traits in sporulation, conidial germination, and pathogenicity. Positive cross‐resistance was only observed between trifloxystrobin and azoxystrobin, but not between trifloxystrobin and carbendazim, isoprothiolane, prochloraz, or chlorothalonil. The point mutation G143S in cytochrome b (cyt b ) protein was found in eight high‐resistance mutants with resistant factor ranging from 2295.16 to 13 200.00; and the double mutation G137R/M296V only occurred in Mg117‐1 with resistance factor ≈ 900. The G143S mutation weakened hydrogen bond interactions, and G137R/M296V changed the conformation of trifloxystrobin in the cyt b binding pocket. A molecular detection method was established for the rapid detection of G143S mutants in M. oryzae . CONCLUSION The resistance risk of M. oryzae to trifloxystrobin could be moderate to high. Two genotypes with three point‐mutations G143S, G137R, and M296V conferred resistance to trifloxystrobin in M. oryzae . © 2020 Society of Chemical Industry