Adaptation to fungicides in Monilinia fructicola isolates with different fungicide resistance phenotypes
Adaptation to fungicides in Monilinia fructicola isolates with different fungicide resistance phenotypes
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DOI：
10.1094/phyto-98-2-0230
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发表时间：
2008-02-01
期刊：
影响因子：
3.2
通讯作者：
Schnabel, Guido
中科院分区：
文献类型：
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作者：
Luo, Chao-Xi;Schnabel, Guido
通过菌丝和分生孢子对选择性杀菌剂浓度的增加和紫外线诱变，评估了不同杀菌剂敏感性表型的果霉菌株对杀菌剂的抗性能力。结果表明，与菌丝转移实验相比，在孢子转移实验中，对喹酮类外源抑制剂(QOI)、嘧菌酯和甾醇去甲基化抑制剂(DMI)杀菌剂丙环唑的适应性更好。与苯并咪唑抗性(BZI-R)和敏感(S)菌株相比，在菌丝和分生孢子转移实验中，耐药株(DMI-R)适应明显更高剂量的嘧菌酯。在BZI-R菌株的分生孢子转移实验中，加入稳定的非致死剂量的甲基托布津时，加速了对丙环唑的适应。来自DMI-R分离株的两个抗嘧菌酯突变株中的一个没有表现出任何适合度惩罚；另一个分离株在进行进一步测试之前就过期了。与亲本菌株相比，该活性突变体对喷洒嘧菌酯的桃离体果造成了更大的病斑。突变株转入原代培养后，活性突变体对嘧菌酯的敏感性恢复到基线水平。然而，在添加0.2和1mU g/ml嘧菌酯的培养基上继代培养后，突变体对嘧菌酯的抗性恢复得比相应的亲本菌株更快，只有突变体而不是亲本菌株能够适应5mU g/ml嘧菌酯。在紫外线诱变实验中，Dmi-R菌株产生的突变株明显多于S菌株。所有紫外线诱变株对杀菌剂的抗性稳定，适合度损失较小。这项研究表明，在缺乏诱变剂的情况下，果蝇对QOI杀菌剂产生抗药性，并为果蝇对DMI杀菌剂抗性菌株的突变性增加和对嘧菌酯加速适应的易感性提供了证据。
The ability to develop fungicide resistance was assessed in Monilinia fructicola isolates with different fungicide sensitivity phenotypes by adapting mycelium and conidia to increasing concentrations of selective fungicides and UV mutagenesis. Results showed that adaptation to Quinone outside inhibitor (QoI) fungicide azoxystrobin and sterol demethylation inhibitor (DMI) fungicide propiconazole was more effective in conidial-transfer experiments compared to mycelial-transfer experiments. DMI-resistant (DMI-R) isolates adapted to significantly higher doses of azoxystrobin in both, mycelial- and conidial-transfer experiments compared to benzimidazole-resistant (BZI-R) and sensitive (S) isolates. Adaptation to propiconazole in conidial-transfer experiments was accelerated in BZI-R isolates when a stable, nonlethal dose of 50 mu g/ml thiophanate-methyl was added to the selection medium. One of two azoxystrobin-resistant mutants from DMI-R isolates did not show any fitness penalties; the other isolate expired before further tests could be carried out. The viable mutant caused larger lesions on detached peach fruit sprayed with azoxystrobin compared to the parental isolate. The azoxystrobin sensitivity of the viable mutant returned to baseline levels after the mutant was transferred to unamended medium. However, azoxystrobin resistance recovered quicker in the mutant compared to the corresponding parental isolate after renewed subculturing on medium amended with 0.2 and 1 mu g/ml azoxystrobin; only the mutant but not the parental isolate was able to adapt to 5 mu g/ml azoxystrobin. In UV mutagenesis experiments, the DMI-R isolates produced significantly more mutants compared to S isolates. All of the UV-induced mutants showed stable fungicide resistance with little fitness penalty. This study indicates the potential for QoI fungicide resistance development in M. fructicola in the absence of a mutagen and provides evidence for increased mutability and predisposition to accelerated adaptation to azoxystrobin in M. fructicola isolates resistant to DMI fungicides.