Silver nanoparticles used to counter Monilinia fructicola fungicide-resistance and reduce fungicide environmental footprint&amp;#160;

Constantinos Chrysikopoulos,Anastasios A Malandrakis,Nektarios Kavroulakis,Anthi Stefanarou

doi:10.5194/egusphere-egu21-9285

Abstract

&lt;div&gt;&lt;span&gt;The potential of silver nanoparticles (Ag-NPs) to control plant pathogen &lt;em&gt;Monilia&lt;/em&gt;&lt;em&gt;fructicola &lt;/em&gt;and to deter environmental contamination by reducing fungicide doses was evaluated &lt;em&gt;in vitro &lt;/em&gt;and &lt;em&gt;in vivo. &lt;/em&gt;&amp;#160;&lt;/span&gt;F&lt;span&gt;ungitoxicity screening &lt;/span&gt;of&amp;#160;&lt;em&gt;&lt;span&gt;M. fructicola&amp;#160;&lt;/span&gt;&lt;/em&gt;&lt;span&gt;isolates resulted in the detection of 18 benzimidazole-resistant (BEN-R) isolates with reduced sensitivity to fungicides &amp;#160;thiophanate methyl (TM)&amp;#160; and carbendazim. All resistant isolates caried the E198A resistance mutation in their &lt;/span&gt;&lt;em&gt;&lt;span&gt;&amp;#946;&lt;/span&gt;-&lt;/em&gt;tubulin gene, target site of the benzimidazole fungicides.&amp;#160;&lt;span&gt;Ag-NPs could effectively control both sensitive (BEN-S) and resistant isolates while the combination of Ag-NPs with TM significantly enhanced their fungitoxic effect both &lt;em&gt;in vitro&amp;#160;&lt;/em&gt;and in apple fruit tests. The positive correlation observed between Ag-NPs and TM+Ag-NPs treatments indicates a mixture-enhanced Ag-NPs activity/availability as a possible mechanism of synergy. No correlation between Ag-NPs&amp;#160; and AgNO&lt;sub&gt;3&amp;#160;&lt;/sub&gt;could&amp;#160; be found suggesting difference(s) in the fungitoxic mechanism of action between Nps and their bulk/ionic counterparts. Indications of the involvement of energy (ATP) metabolism in the mode of action of Ag-NPs were also evident by the synergy observed between Ag-NPs and the &lt;/span&gt;oxidative phosphorylation&lt;span&gt;-uncoupler fluazinam (FM) against both BEN-R and BEN-S phenotypes. The role of silver ions release on the inhibitory action of Ag-NPs against the fungusis probably limited since the AgNPs/NaCl combination enhanced fungitoxicity, a fact that could not be justified by the expected binding of silver with chlorine ions. Concluding, Ag-NPs can be effectively used as a means of controlling both BEN-S and BEN-R &lt;em&gt;M.&amp;#160;&lt;/em&gt;&lt;em&gt;fructicola&amp;#160;&lt;/em&gt;isolates &lt;/span&gt;while&amp;#160;&lt;span&gt;their combination with conventional fungicides should aid anti-resistant strategies and reduce the environmental impact of synthetic fungicides by reducing effective doses to the control the pathogen.&lt;/span&gt;&lt;/div&gt;

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