Mechanisms and management of carbendazim resistance in Gibberella zeae
M. G. ZHOU (1), J. Yu (1), J. Qiu (1), C. Chen (1), Y. Zhang (1), Y. Hou (1). (1) Nanjing Agricultural University, Nanjing, China
In China, <i>Gibberella zeae</i> is dominant pathogen causing wheat head blight. Carbendazim (MBC) has been widely used to control this disease since the 1970s. However, the resistance to MBC was popular in <i>G. zeae</i> currently. Though the MBC-resistance was controlled by one major gene and involved in the mitotic division, no mutation in the target <i>β</i>-tubulin was found, different from other filamentous fungi. To identify the MBC-resistance mechanism of <i>G. zeae,</i> other members of tubulin genes were analyzed. Alteration at amino-acid codon 17 or 167 or 198 or 200 in <i>β<sub>2</sub></i>-tubulin was found to corresponding to the different phenotypes of MBC-sensitivities. Deletion/complementation of the <i>β<sub>2</sub></i>-tubulin gene as well as mononucleotide displacement and affinity of MBC binding tubulins validated the point mutation conferring resistance of <i>G. zeae</i> to MBC. It is interested to find that MBC-resistance mutation leads to the increase in expression of deoxynivalenol (DON) biosynthesis genes. Compared to wild-type MBC-sensitive strain, resistance strain produced twice of DON in infected grains. Novel chemical 2-cyano-3-amino-3-phenylancryic acetate is recommended as a <i>Fusarium</i> specific fungicide to control MBC-resistance Fusarium head blight.
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