Student:	Mehmet DEMİRALAY
Supervisor:	Prof. Dr. Asım KADIOĞLU
Department:	Biyoloji
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University Turkey

Title of the Thesis:	INVESTIGATION OF RELATIONSHIP BETWEEN POLYAMINE METABOLISM AND HYDROGEN PEROXIDE UNDER DROGHT STRESS
Level:	Ph.D.
Acceptance Date:	17/6/2015
Number of Pages:	87
Registration Number:	Di1086

Summary:

The expression levels of the genes, which take part in polyamine metabolism, such

as arginine dekarboxylase, agmatine iminohidrolase/deaminase, spermidine synthase, Sadenosyl

methionine decarboxylase, diamine oxidase/copper amino oxidase and polyamine

oxidase were determined by RT PCR under drought stress after exogenious hydrogen

peroxide (H2O2), diphenyleneiodonium chloride, difluoromethyl arginine and

difluoromethyl ornithine treatments. Content of abscisic acid (ABA) and expression level

of abscisic aldehyde oxidase gene that has a role in abscisic acid synthesis were

determined. In addition to ABA, proline content, and the expression levels of pyrroline 5

carboxylate synthase and proline deyhdrogenase were determined. Polyamine levels

(putrescine, spermidine and spermine), our critical parameter in determining the

relationship were measured by HPLC. According to data, exogenous H2O2 induced

polyamine synthesis by up regulating polyamine synthesizing genes and down regulation

polyamine degredating genes. Moreover, H2O2 suprressed ABA synthesis and induced

proline synthesis. In conclusion, exogenous H2O2 that was applied at a low contentration

affected polyamine metabolism toward sysnthesis. On the contrary the polyamine

degredating genes were suppressed by H2O2. It was determined that H2O2 started a

signaling cascade in polyamine metabolism.

Key Words: Drought, Hydrogen peroxide, polyamine, putrescine, spermidine, spermine,

abscisic acid, (ABA), Zea mays L.