Identification of cytokinins produced by the plant parasitic nematodes Heterodera schachtii and Meloidogyne incognita

SUMMARY The presence of different types of cytokinins was analysed in exudates and lysates of stage‐2 juveniles of Heterodera schachtii and Meloidogyne incognita and in mixed stages of Caenorhabditis elegans . For all species, cytokinins were detected in lysates and exudates in which benzyladenine and zeatin‐type cytokinins were the most prominent forms. The production of cytokinins by Meloidogyne was much higher than by Heterodera , and the detected levels were in a range which interfered with the physiological activities of the host plant. The presence of 5‐methoxy‐N,N‐dimethyltryptamine hydrogen oxalate did not affect hormone production by H. schachtii , whereas resorcinol slightly stimulated hormone production by M. incognita . The exuded cytokinins may play a role in feeding site induction, more particularly in cell cycle activation and in establishing the feeding site as a nutrient sink.