Inhibition of Phytophthora parasitica and P. capsici by Silver Nanoparticles Synthesized Using Aqueous Extract of Artemisia absinthium

Abstract

Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and ecofriendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg ml⁻¹ of AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50: 2.1 to 8.3 µg ml⁻¹) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

Fungicidal and antibacterial activity of the hydrogel compositions with silver

“…If D/D0=0.5, the index IR according to (2), is also equal to 0.5. Substituting IR=0.5 in (4), we take into account the ratios (5):…”

“…Substituting in (3) the value of D/D0=0 to calculate ЕСt, required value as mentioned above, will be equal to a (ЕСt=a). Indicator IR at D/D0=0 will be equal to its maximum value -unity, according to (2). But in this case, model (4) by substituting IR=1 gives the following expression:…”

“…In a storage period, rot had destroyed 30-40% of tubers [1]. Average worldwide losses reach 8-10%, which is worth of several billion dollars [2]. In some European countries like Poland, losses can reach 20-25% annually [3].…”

“…Such causative agents as late blight and black leg of potato were used for the laboratory experiments. Unlike previous studies [2,[10][11][12][13][14], this research involves the assessment of non-water solutions such as gel compositions of the PPA with colloidal and ionic form of silver nitrate (AgNO3). These compositions improve the stability of the nanoparticles, and in the practical use guarantee fixation of PPA in the rhizosphere and its protection from leaching.…”

“…Two main objectives of the research are as follows: 1) to assess the antifungal and antibacterial effects of gel compositions with silver in order to determine the range of PPA doses for subsequent trials under field conditions; 2) to compare the effectiveness of different forms of silver and different types of hydrogels. Based on the previous studies [2,[10][11][12][13][14][15][16], the dose of silver should not exceed 100 ppm, which is economically sufficient considering an average price of silver 15-30$ per Trinity oz.. This study compared the efficiency of the two agents, as well as several types of hydrogels: a convenient "Aquasorb" based on polyacrylamide and new hydrogels produced at the Ural Chemicals Factory by our proprietary technology with the filling of the polymer matrix.…”