The Role of Auxins in Interactive Relationships between Plants and Pathogens

This study aimed to elucidate the importance of plant hormones regulating plant growth, especially auxin (indoleacetic acid). The study showed that this hormone is produced by both plants and microorganisms such as bacteria and fungi through different metabolic pathways, yet they produce the same auxin . The amino acid tryptophan is a primary source in the biosynthesis of indoleacetic acid. Research has shown the role and effectiveness of auxin in plants, as well as its role in the interactions between plants and pathogens, and its effect on pathogens varies positively or negatively. It is important in the symbiotic relationships between root nodule bacteria and plants and mycorrhizae and plants that promote plant growth and increase its resistance to pathogens. Additionally, auxin influences the growth and pathogenicity of plant pathogenic fungi and increases the pathogenicity of fungal pathogens.Hormones are present in plant tissues, where more than one hormone may be found in a single tissue. Hormones are characterized by their action within the same cell or by their ability to move to another location and exert their effects there. They are naturally occurring, but when synthesized chemically, they are called growth regulators . The effects of hormones differ; auxins and gibberellins, for example, promote stem elongation , but their mechanisms of action vary On the other hand, abscisic acid and ethylene inhibit stem growth, dividing them into two groups : growth promoters, which stimulate plant growth, such as auxins, gibberellins, and cytokinins .The second group consists of growth inhibitors represented by abscisic acid and ethylene .