Application of silver nanoparticles for the control of pepper (Capsicum annuum) soft rot disease factor Pectobacterium carotovorum

Nanoparticle application areas include stimulation of plant growth, development and control of plant pathogens. Silver is one of the most produced and used metal nanoparticles. Silver has known for its antimicrobial effect for centuries and now in the nanoform it has gained unique feautures like high surface/volume ratio, conductivity, thermal stability. In this study, we investigated the antimicrobial effect of phytosynthesized AgNPs to control a plant pathogen Pectobacterium carotovorum that causes soft rot dieases on pepper seedlings. Pepper seedlings were grown under greenhouse conditions and were infected by this bacteria when they were in four leaves stage. AgNP in different concentrations and antibiotics were applied two days after the infection. Synthesized silver nanoparticles were characterized by using UV/Vis spectrophotometer, Fourier transform infrared spectroscopy (FT-IR) and Zeta sizer. According to spectrofotometric measurment, the highest peaks, obtained from UV/Vis spectrophotometer, were between 400 and 435 nm corresponding to plasmon resonance of AgNPs. Fourier Transform Infrared Spectroscopy (FT-IR) results showed that, these nanoparticles are naturally coated with phytocontent. Zeta sizer results showed that nanoparticle size was 180 nm and its zeta potential was -11 mV. The effects of infection and other applications on seedlings was determined by tests like MDA content, H2O2 content, chlorophyll content analysis. In the In vitro studies MBC value of AgNP was determined as 500 ppm. The dieases indicincy was found as 10.47% for antibiotics, 31.86% and %13.52 for 250 and 500 ppm AgNP respectively. Based on these analysis results there has been no significant oxidative stress effect of nanoparticles and infection, they only affected the membran integration and chlorophyll content slightly. That showed us these nanoparticles can be used against plant pathogens but further investigations are needed.