Cadmium and Zinc Induced Similar Changes in Protein and Glycoprotein Patterns in Tobacco (Nicotiana tabacum L.) Seedlings and Plants

The effects of 10 μmol L-1 and 15 μmol L-1 cadmium (Cd), a nonessential toxic element and 25 μmol L-1 and 50 μmol L-1 zinc (Zn), an essential micronutrient, on proteins and glycoproteins of Nicotiana tabacum L. seedlings and plants were investigated after exposure to each metal alone or to their combinations. Changes in only few polypeptides related to heavy metal treatments were observed in tobacco seedlings and leaves of adult plants, while the greatest change in total soluble protein pattern was observed in plant roots. Differences between control and treated tobacco tissues were more pronounced in the glycoprotein pattern, which was analysed by application of different lectins. The majority of the detected glycoproteins in leaves and roots of adult plants can be considered as a result of enhanced glycosylation due to heavy metal stress. The difference in glycoproteins between Cd and Zn application on tobacco seedlings and adult plants could not be determined since enhanced glycosylation was noticed after treatment with either metal alone or in combination. Therefore, it can be concluded that both metals induced N- and Oglycosylation as a result of changed environmental conditions.
Ispitivali smo učinke 10 μmol L-1 i 15 μmol L-1 kadmija (Cd), neesencijalnoga toksičnog elementa i 25 μmol L-1 i 50 μmol L-1 cinka (Zn), esencijalnog mikronutrijenta, na proteine i glikoproteine u klijancima i odraslim biljkama Nicotiana tabacum L. nakon izlaganja svakomu metalu posebno ili njihovim kombinacijama. Promjene kod nekoliko polipeptida koje su uočene u klijancima i listovima odraslih biljaka nisu bile brojne, dok su one najvažnije zabilježene u uzorku ukupnih topljivih proteina u korijenu biljke. Razlike između kontrole i tretiranog tkiva duhana bile su izraženije kod glikoproteina koji su analizirani primjenom različitih lektina. Većina glikoproteina uočenih u listovima i korijenu odraslih biljaka može se smatrati rezultatom povećane glikozilacije zbog stresa koji uzrokuju teški metali. Nije bilo moguće utvrditi razliku u glikoproteinima između tretiranja klijanaca i odraslih biljaka duhana kadmijem i cinkom jer je povećana glikozilacija utvrđena i nakon tretmana svakim metalom posebno i nakon tretmana njihovim kombinacijama. Stoga se može zaključiti da su, kao rezultat promijenjenih uvjeta u okolišu, oba metala potaknula N- i O-glikozilaciju.