In accordance with the central roles of phytohormones in cellular differentiation and organ morphogenesis, a growing body of experimental evidence indicates that plant-parasitic cyst and root-knot nematodes interfere with hormonal biosynthesis pathways and their signal transduction cascades to drive the infected root cells into becoming specialized new feeding cells. Recently, we determined the expression patterns of 22 auxin response factors (ARFs) in the syncytia induced by the beet cyst nematode in Arabidopsis roots. The expression patterns suggested roles of ARFs in syncytium initiation and establishing its maximum size by incorporating neighboring cells with the initial feeding cells, as well as in maintaining the functional phenotype of fully-developed syncytium. Also, our results indicate that formation of syncytium and giant-cell is mediated by modulation of cytokinin and ethylene signaling. We are interested in elucidating the induced hormonal crosstalk that modulates plant-nematode interactions.