| Title | Involvement of Alternative Oxidase in the Regulation of Sensitivity of Sclerotinia sclerotiorum to the Fungicides Azoxystrobin and Procymidone |
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| Author | Ting Xu1,2, Ya-Ting Wang1,2, Wu-Sheng Liang1,2*, Fei Yao1,2, Yong-Hong Li3, Dian-Rong Li3, Hao Wang3, and Zheng-Yi Wang1,2 |
| Address | 1Institute of Biotechnology, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, P. R. China, 2State Key Laboratory of Rice Biology, Hangzhou 310058, P. R. China, 3Hybrid Rapeseed Research Center of Shaanxi Province, Dali 715105, P. R. China |
| Bibliography | Journal of Microbiology, 51(3),352-358, 2013, |
| DOI | 10.1007/s12275-013-2534-x |
| Key Words | Sclerotinia sclerotiorum, alternative oxidase, mitochondrial respiration, azoxystrobin, procymidone, fungicide sensitivity |
| Abstract | Sclerotinia sclerotiorum is a filamentous fungal pathogen that can infect many economically important crops and vegetables. Alternative oxidase is the terminal oxidase of the alternative respiratory pathway in fungal mitochondria. The function of alternative oxidase was investigated in the regulation of sensitivity of S. sclerotiorum to two commercial fungicides, azoxystrobin and procymidone which have different fungitoxic mechanisms. Two isolates of S. sclerotiorum were sensitive to both fungicides. Application of salicylhydroxamic acid, a specific inhibitor of alternative oxidase, significantly increased the values of effective concentration causing 50% mycelial growth inhibition (EC50) of azoxystrobin to both S. sclerotiorum isolates, whereas notably decreased the EC50 values of procymidone. In mycelial respiration assay azoxystrobin displayed immediate inhibitory effect on cytochrome pathway capacity, but had no immediate effect on alternative pathway capacity. In contrast, procymidone showed no immediate impact on capacities of both cytochrome and alternative pathways in the mycelia. However, alternative oxidase encoding gene (aox) transcript and protein levels, alternative respiration pathway capacity of the mycelia were obviously increased by pre-treatment for 24 h with both azoxystrobin and procymidone. These results indicate that alternative oxidase was involved in the regulation of sensitivity of S. sclerotiorum to the fungicides azoxystrobin and procymidone, and that both fungicides could affect aox gene expression and the alternative respiration pathway capacity development in mycelia of this fungal pathogen. |