It has been recognized that cytokinins are plant hormones that influence not only
numerous aspects of plant growth, development and physiology, including cell division,
chloroplast differentiation and delay of senescence but the interaction with other
organisms, including pathogens. Cytokinins are not only produced by plants but are
also by other prokaryotic and eukaryotic organism such as bacteria, fungi, microalgae and
insects. Notably, cytokinins are produced both by pathogenic and also beneficial
microbes and are known to induce resistance in plants against pathogen infections. In
this review the contrasting role of cytokinin for the defence and susceptibility of plants
against bacterial and fungal pathogen and pest insects is assessed. We also discuss the
cross talk of cytokinins with other phytohormones and the underlying mechanism involved
in enhancing plant immunity against pathogen infections and explore possible practical
applications in crop plant production.