Abstract
Besides roles of cytokinins as a plant growth promoting hormone on specification of embryonic cells, maintenance of meristemetic cells, and vasculature development, cytokinins have been emerged as a major player in plant-microbe interactions during nodule organogenesis and pathogenesis. Microbe-originated cytokinins confer abnormal hypersensitivity of cytokinins to plants augmenting the sink activity of infected region. However, recent discovery shed light on a distinct role of cytokinins in plant immune responses. Plant-borne cytokinins systemically induce resistance against pathogen infection, orchestrated by endogenous cytokinin and salicylic acid signaling. I will discuss how plant- and pathogen-derived cytokinins inversely affect plant defense response and, furthermore, present molecular mechanisms underlying plant-derived cytokinin action in the plant immunity.
