Journal of Pure and Applied MicrobiologyVol. 7 No. 2

Sensitivity of Corynespora cassiicola to Carbendazim and Diethofencarb

Daye Huang1, Yanxia Shi2, Xuewen Xie2, Weiping Wang1 and Baoju Li2*

1College of Plant Protection, Shenyang Agricultural University, Shenyang , Liaoning Provinces, China, 2 Insititute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China.

Received on 09 October 2012 and accepted on 01 December 2012

 

ABSTRACT

During 2005 and 2011, 159 isolates of Corynespora cassiicola were collected from 10 different provinces in China, and their sensitivities to carbendazim and diethofencarb were determined. Among all isolates, 8.2% were sensitive to carbendazim (MS), 91.8% were highly resistant to carbendazim (MHR) and 14.5% were highly resistant to both carbendazim and diethofencarb (MHRNHR), moderately resistant isolates to carbendazim were not found. This is the first report of C. cassiicola isolates that were highly resistant to both carbendazim and diethofencarb. As compared to MS isolates, MHR and MHRNHR isolates showed similar fitness in fungal growth rate, sporulation and pathogenicity. Carbendazim resistance correlated with a single mutation in b–tubulin gene C. cassiicola amplified with primer pair b–tubf1-F and b–tubf1-R causing a change of glutamic to alanine at amino acid 198. Furthermore, the substitution of glutamic acid to lysine and phenylalanine to tyrosine led the resistance to both fungicides at amino acid 198 and 200 repecetively.

Keywords : Corynespora cassiicola, Carbendazim, Diethofencarb, b–tubulin.