ZnO nanoparticle Induced expression of hyoscyamine biosynthesis related genes in Datura metel plant leaves

Abstract

Background. The medicinal herbs have been traditionally used for various human and veterinary disease. Chemical compounds such as secondary metabolites are responsible for the therapeutical effects of these herbs. The tropane alkaloids (TAs), especially hyoscyamine, scopolamine and atropine, are one of most known secondary metabolites and exist in pants such Datura metel which act as protective molecules in stressful conditions. Recently, many endeavors have been done for mass production of TAs. Here we have tried to investigate the effect of ZnO nanoparticles on production of TAs through assessment of key-stone enzymes in TAs biosynthesis including Putrescine N-methyltransferase (PMT), tropinone reductase 1 (TR-I)

and hyoscyamine 6β-hydroxylase enzyme

Method & Material. Primarily, the Datura metel seeds were purchased from PAKAN BAZR co., Isfahan, Iran. After sterilization using ethanol 70% and sodium hypochlorite 20%, they were cultured in MS media containing vermiculite and peat through incubation at RT. afterward, the seedlings were transferred into the vase and subsequently were treated by ZnO nanoparticle which was bought from Diptronic company, Tehran, Iran and sprayed at their leaves. Finally, the RNA was extracted from powder of their leaves prepared via liquid nitrogen. After cDNA synthesis, the expressions of given enzymes were measured by Real Time-PCR.

Result. Our results demonstrated that ZnO nanoparticles have triggered the plants to increase the expression of enzymes that mediate the biosynthesis of hyoscyamine and scopolamine. The data displayed that ZnO nanoparticles had led to increment of PMT, TR-I and H6H, though statistically significant increase had been observed only at 15 mg/ml genes more than 4 and 3-folde for PMT and TR-I, respectively, and more than 2 and 3-times in turn at 5 and 15 mg/ml for H6H gene.

Conclusion. We showed that induction of stress to this plant cells results in higher yield of TAs as the genes who advance the biosynthesis of TAs, had been upregulated in response ZnO nanoparticles as stress-inducing stimuli. Based on studies, we hypothesize that oxidative stresses resulted from ZnO could activate the anti-oxidant defense system and upregulate related genes such as those who synthesize the ATs as protective molecules.