STUDIES ON TOMATO WILT CAUSED BY FUSARIUM OXYSPORUM F . SP . LYCOPERSICI IN KAZACHESTAN . 2 : EFFECT OF EXOGENOUS APPLICATION OF PLANT EXTRACTS AND SAFE CHEMICALS AS RESISTANCE INDUCER TREATMENTS ON THE ACTIVETY OF THE OXIDATIVE ENZYMES

In this study, tomato (Carolina Gold cv.) transplants were treated before planting in pots with garlic (G), black pepper (BP) extracts (at 0.5 & 4.0% conc.), salicylic acid (SA) or riboflavin (R) at 0.1 & 10.0mM conc. using different application methods (immersing roots “IR”, spraying shoots “SS” and IR+SS) then inoculated with the tomato wilt fungus Fusarium oxysporum f. sp. lycopercici (FOL). The activities of polyphenoloxidase (PPO) and peroxidase (POD) enzymes were determined in leaves of treated and untreated (control) tomato plants after two months from inoculation. The increase in POD activity was higher and more pronounced than activity of PPO. Comparing to the control treatment, the increase in PPO activity, in most treatments, was ranged between 4.4% (IR/SS/BP at 4%) to 94.2% (SS/R at 0.1mM) although few treatments slightly decreased it. However, all tested treatments increased activity of POD enzyme. The rate of increase was ranged between 60.7 to 1000.0%. INTRODUCTION Infection of tomato with Fusarium oxysporum f. sp. lycopercici (FOL) wilt significantly reduced the crop yield and quality (Aba AlKhail, 2005). The use of resistant varieties is the best strategy for disease control (Silva and Bettiol, 2005) and (Sheu and Wang, 2006). Controlling of plant diseases mainly depend on fungicides treatments (Rauf, 2000; El-Mougy et al., 2004). However, fungicidal applications cause hazards to human health and increase environmental pollution. Therefore, alternatives, eco-friendly approach treatments for control of plant diseases are needed (Abd-El-Kareem, 2007; Rojo et al., 2007; Mandal et al., 2009). Systemic acquired resistance (SAR) or induction of resistance to pathogen is a promising approach for controlling plant diseases. Exogenous or endogenous factors could substantially affect host physiology, leading to rapid and coordinated defense-gene activation in plants normally expressing susceptibility to pathogen infection (Mandal et al., 2009). This phenomenon, that resistance of plant to pathogens can be enhanced by the application of various biotic and a biotic agent, called induce systemic resistance in plants (Yedidia et al., 2000; Brimner and Boland, 2003; Sarwar et al., 2005; AbdEl-Kareem, 2007). Use of chemical inducer, salicylic acid (SA) represents an interesting new opportunity in controlling fungal and bacterial diseases within an environmental friendly integrated crop protection system through enhancing the resistance of the plant to pathogen (Oostendorp et al., 2001; Ellis et al., 2002; Balciuniene et al., 2005; El-Khallal, 2007a; El-Khallal, 2007b; Khaosaad et al., 2007; Ali et al., 2009; Mandal et. al., 2009). The signal molecule SA is involved in some signal transduction system, which induce particular enzymes catalyzing biosynthetic reactions to form defense compounds such as polyphenols, pathogenesisrelated (PR) proteins (Métraux, 2001; Shah, 2003; Vimala and Suriachandraselvan, 2009). In plants the positive correlation between levels of polyphenol oxidase (PPO) and peroxidase (POD) and the resistance to pathogens and herbivores is frequently observed. There are some evidences indicating that the activation of peroxidase, polyphenol oxidase plays a crucial role in the biological control and resistance of plant to pathogenic attack (Mohammadi and Karr, 2002; Thipyapong et al., 2004;