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This study examined the effects of different concentrations of spermine (Spm) and putrescine (Put) elicitors on capsaicin production at different times in cell suspension culture of peper (<em>Capsicum annuum </em>L‘Kahramanmaraş Hat-187’<em>.</em>), raised from pepper seeds. Callus was obtained from hypocotyl explants of pepper seedlings germinated <em>in vitro</em> conditions, and cell suspensions were prepared from calluses. Spm (0.1, 0.2 and 0.4 mg l^-1) and Put (0.1, 0.2 and 0.4 mg l^-1) elicitors were applied on cell suspensions, and control groups free from elicitor treatment were created. The amount of capsaicin in cells was found to be higher in the control groups and samples treated with Spm elicitors when compared to filtrates. The highest increase in the capsaicin amount in cells was determined on day 12 of elicitation with 0.2 mg l^-1Spm application. The highest capsaicin amount passing into the filtrate was determined as 0.1 mg l^-1Spm on day 8. The most effective Put concentration and time on capsaicin amount were found as 0.2 mg l^-1Put on day 12 in both cells and filtrates. The highest total capsaicin was also determined in the 0.2 mg l^-1Spm application on day 12with 312.747 ± 8.70 µg g^-1 of culture. Exogenous treatment of Spm and Put elicitors affected capsaicin accumulation.

Phytophthora capsici (P. capsici) causes root rot, a deadly plant disease. Resistance to diseases is produced by the activation of many defense substances, so knowledge of this natural defense mechanism allows the development of new strategies for disease control. In this study, the response of nitrate (NO3-), which is effective in plant growth and development, in different pepper genotypes exposed to pathogen infection was investigated. For this, resistant and sensitive pepper genotypes were exposed to 102, 103 and 104 zoospore/mL of P. capsici-22 strain and changes in NO3- content were determined from root samples taken on the 2nd, 4th and 6th days after infection. All zoospore concentrations resulted in an overall increase in NO3- content in roots of CM-334 on all days. In KM-181 and SD-8 genotypes, the highest NO3- content was determined on the 6th day of 103 zoospore/mL application. In SD-8 and KM-181 genotypes, a significant decrease in tha amount of NO3- was determined on the 4th and 6th days of treatment of 104 zoospore/mL. In these genotypes, a decrease in the amount of NO3- was found with the increase in infection time at high zoospore concentration. When the three pepper genotypes were compared, the highest NO3- content was determined in the resistant CM-334 genotype, which was exposed to 104 zoospore/mL on the 6th day following the infection. In this study, changes in the amount of NO3- in resistant and susceptible pepper genotypes indicated that NO3- may be effective in plant defense against P. capsici-22.

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