Inhibiting Copper Amine Oxidase Using L-Aminoguanidine Induces Cultivar and Age-Dependent Alterations of Polyamine Catabolism in Tomato Seedlings

Many effects of polyamines (PAs) are well known in plant developmental processes; however, the significance of their catabolism is not well understood. Copper amine oxidase (CuAO) is involved in the degradation of diamine putrescine (Put). The genotype dependence and time-dependent effects of this enzyme are rarely examined, so this study aims to discover the role of CuAO in tomato genotypes in different stages of seedling development. Exogenously applied L-aminoguanidine (AG), a CuAO inhibitor, was used to decrease the activity of CuAOs. Based on our results, it can be concluded that there is a genotype dependence of Put degradation, and AG treatment caused a long-term shift of PA catabolism by changing the activities of polyamine oxidase (PAO), catalyzing the degradation of higher PAs. Our results demonstrate that the modification of PA catabolism could have long-term results in polyamine metabolism in different tomato genotypes.