Buysens Catherine, Dupré de Boulois Hervé, Declerck Stéphane
Earth and Life Institute, Applied Microbiology, Mycology, Université Catholique de Louvain, Croix du Sud, 2 box L7.05.06, 1348, Louvain-la-Neuve, Belgium.
Mycorrhiza. 2015 May;25(4):277-88. doi: 10.1007/s00572-014-0610-7. Epub 2014 Oct 15.
There is growing evidence that the application of biocontrol organisms (e.g., Pseudomonas and Bacillus spp., arbuscular mycorrhizal fungi-AMF) is a feasible option to reduce incidence of plant pathogens in an integrated control strategy. However, the utilization of these microorganisms, in particular AMF, may be threatened by the application of fungicides, a widely-used measure to control Rhizoctonia solani in various crops among which potato. Prior to their application, it is thus important to determine the impact of fungicides on AMF. The present study investigated, under in vitro controlled conditions, the impact of azoxystrobin (a systemic broad-spectrum fungicide), flutolanil (a systemic Basidiomycota-specific fungicide), and pencycuron (a contact Rhizoctonia-specific fungicide) and their respective formulations (Amistar, Monarch, and Monceren) on the growth and development of the AMF Rhizophagus irregularis MUCL 41833 (spore germination, root colonization, extraradical mycelium development, and spore production) at doses used to control R. solani. Results demonstrated that azoxystrobin and its formulation Amistar, at threshold values for R. solani control (estimated by the half maximal inhibitory concentration, IC50, on a dry weight basis), did not affect spore germination and potato root colonization by R. irregularis, while the development of extra-radical mycelium and spore production was reduced at 10 times the threshold value. Flutolanil and its formulation Monarch at threshold value did not affect spore germination or extra-radical development but decreased root colonization and arbuscule formation. At threshold value, pencycuron and its formulation Monceren, did not affect spore germination and intra- or extraradical development of R. irregularis. These results suggest that azoxystrobin and pencycuron do not affect the AMF at threshold concentrations to control R. solani in vitro, while flutolanil (as formulation) impacts the intraradical phase of the fungus. These fungicides and R. irregularis thus have the potential to be used in parallel against Rhizoctonia disease in potato.
越来越多的证据表明，在综合防治策略中应用生物防治生物（如假单胞菌属和芽孢杆菌属、丛枝菌根真菌-AMF）是降低植物病原体发病率的可行选择。然而，这些微生物的利用，尤其是AMF，可能会受到杀菌剂应用的威胁，杀菌剂是一种广泛用于控制包括马铃薯在内的各种作物中茄丝核菌的措施。因此，在应用之前，确定杀菌剂对AMF的影响很重要。本研究在体外控制条件下，研究了嘧菌酯（一种系统性广谱杀菌剂）、氟酰胺（一种系统性担子菌特异性杀菌剂）和戊菌隆（一种接触性丝核菌特异性杀菌剂）及其各自的制剂（阿米西达、君主、和满穗）在用于控制茄丝核菌的剂量下对AMF不规则球囊霉MUCL 41833生长发育（孢子萌发、根部定殖、根外菌丝发育和孢子产生）的影响。结果表明，嘧菌酯及其制剂阿米西达在控制茄丝核菌的阈值浓度（以干重计的半数最大抑制浓度IC50估计）下，不影响不规则球囊霉的孢子萌发和马铃薯根部定殖，而在阈值浓度的10倍时，根外菌丝发育和孢子产生减少。氟酰胺及其制剂君主在阈值浓度下不影响孢子萌发或根外发育，但会减少根部定殖和丛枝形成。在阈值浓度下，戊菌隆及其制剂满穗不影响不规则球囊霉的孢子萌发和根内或根外发育。这些结果表明，嘧菌酯和戊菌隆在体外控制茄丝核菌的阈值浓度下不影响AMF，而氟酰胺（作为制剂）影响真菌的根内阶段。因此，这些杀菌剂和不规则球囊霉有潜力并行用于防治马铃薯丝核菌病。
