Changes in ultrastructure, proteome and photosynthetic fficiency of tobacco seedlings (Nicotiana tabacum L.) exposed to silver nanoparticles and ions

Nanočestice srebra (AgNP) se zbog antimikrobnih svojstava koriste u širokom spektru nanotehnoloških proizvoda, koji se, između ostaloga, koriste u medicini, prehrambenoj tehnologiji i proljoprivredi. Toksičnost AgNP dokazana je na brojnim organizmima, a ovisi o veličini, obliku i površinskom naboju nanočestica, tipu molekula-omotača i otpuštanju iona srebra. Duhan (Nicotiana tabucum L.) je ekonomski važna kultura i u molekularnoj biologiji uvriježen modelni organizam. U ovom diplomskom radu istražila sam utjecaj AgNP istog oblika, veličine i koncentracije, a stabiliziranih različitim omotačima (bPEI, citrat ili PEG), na klijance duhana. Sjemenke duhana isklijavala sam u tekućem mediju s dodatkom različitih AgNP ili srebrovog nitrata u koncentraciji 100 μM, a u slučaju kontrole bez dodatka srebra. Klijance sam koristila za istraživanje desetog dana tretmana. Tretmani su inhibirali rast korijena, narušili strukturu meristema korijena i uzrokovali promjene u ultrastrukturi kloroplasta. Sadržaj fotosintetskih pigmenata i parametri fluorescencije klorofila također su bili promijenjeni. Proteom klijanaca duhana pokazao je povećanu ekspresiju proteina prvenstveno vezanih uz fotosintezu i odgovor na stres. Nekoliko proteina pokazalo je različit odgovor na nanočestice i ione srebra. AgNP različitih omotača utjecale su na klijance duhana na različit način, no pokazale su se toksičnijima od iona srebra iste koncentracije.Silver nanoparticles (AgNPs) are used for their antimicrobial properties in a wide variety of nanotechnology products used in many fields, including medicine, food technology, and agriculture. The toxicity of AgNPs was proven on many organisms and depends on their size, shape, surface charge, type of coating and release of silver ions. Tobacco (Nicotiana tabucum L.) is an important cash crop and an established model organism in molecular biology. In this thesis, I investigated the influence of AgNPs of the same shape, size, and concentration and stabilised with different coatings (bPEI, citrate or PEG) on tobacco seedlings. Tobacco seeds were germinated in liquid medium containing different AgNPs or silver nitrate in 100 μM concentration. In the case of control, no silver was added. The seedlings were used for research on the tenth day of the treatment. The treatments inhibited root growth, disrupted root meristem structure and caused changes in chloroplast ultrastructure. Photosynthetic pigments' content and chlorophyll fluorescence parameters also changed. Tobacco seedling proteome showed an increased expression of proteins, primarily related to photosynthesis and stress response. A few proteins differed in response to AgNP and silver ion treatment. Differently coated AgNPs affected tobacco seedlings in a different manner and showed to be more toxic than silver ions of equal concentration