Induction and Characterization of Laboratory Mutants of Phytophthora capsici Resistant to Dimethomorph and Flumorph

作     者：YUAN Shan-kui LIU Xi-li GU Bao-gen DONG Jin JIANG Hui SI Nai-guo 

作者机构：Department of Plant Pathology College of Agronomy and Biotechnology China Agricultural University Beijing 100094 P.R.China Center of Agrochemicals for Biological and Environmental Technology Institute for the Control ofAgrochemicals Ministry of Agriculture Beijing 100026 P.R.China Temasek Life Sciences Laboratory National University of Singapore Singapore 117604 Singapore Shenyang Research Institute of Chemical Industry Shenyang 110021 P.R.China 

出 版 物：《Agricultural Sciences in China》 (中国农业科学（英文版）)

年 卷 期：2005年第4卷第10期

页      面：752-759页

学科分类：09[农学] 0901[农学-作物学] 

基　　金：This study was supported by China Postdoctoral Science Foundation(20040350377) National Natural Science Foundation of China(30400294) 

主　　题：Phytophthora capsici Resistance Dimethomorph Flumorph Metalaxyl 

摘      要：Laboratory studies were conducted to evaluate the risk of Phytophthora capsici developing resistance to two morphlines, dimethomorph and flumorph. Metalaxyl, the well-known high risk of resistance fungicides, was used as reference fungicide. Resistant mutants for the three fungicides were isolated by treating mycelium with ultraviolet radiation. Metalaxyl-resistant mutants were obtained with high frequency and exhibited high level of resistance with factors more than 100 folds, while mutation frequency for dimethomorph-resistance was relatively low and the resistance factors ranged from 3.0 to 13.9 folds. Most dimethomorph-resistant mutants decreased in hyphal growth rate and the spoulation ability, which have a large impact upon the epidemic development of dimethomorph-resistant populations. These results suggested that the risk of resistant pathogen population was much lower for dimethomorph than for metalaxyl. Both the frequency of developing resistance and level of resistance （resistance factors = 1.8-14.6） to dimethomorph were similar to those of its structure analogue flumorh. Moreover, the cross-resistance were found between them, which suggested the risks of developing resistance to dimethomorph and flumorph in the pathogen were very closely related. As P. capsici can potentially develop resistance to dimethomorph and flumorph, and oomycetes usually have the high risk to develop resistance to fungicides, appropriate management against resistance development should be taken.