Abstract: Used the Meloidogyne incognita susceptible and resistant Xinjiang wild cherry plum’s greenwood cutting seedlings as the materials，the diversity of nematode infection amount，giant cell’s development and CCS52B expression between susceptible and resistant plants were observed. The results show that the number of M. incognita infected into susceptible plants is significantly higher than resistant ones. In susceptible plants，a large number of nematodes had established feeding sites 5 days after inoculation. After 21 days，these nematodes matured and completed its life cycle. But in resistant plants，only a small number of feeding sites were observed 7 days after inoculation. Twenty-one days after inoculation，most nematodes’ development were arrested，few can develop into adults 35 days afterinoculation. The area of gaint cell and nuclei surface in susceptible plants are significantly larger than resistant plants’. CCS52 is a family of endocycle activator genes，essential for endore-duplication and ploidy-dependent cell enlargement. CCS52B is gaint cell-specific expression in Xinjiang wild cherry plum. Besides，its expression in susceptible plants is stronger than in resistant ones，indicating the involvement of CCS52B in the gaint cell’s formation and development. Such involvement benefits nematodes to establish feeding sites and to complete its life cycle much easier in susceptible plants than in resistant ones. Its high expression in susceptible plants enhanced endoreduplication and increased the giant cell nucleus ploidy，both of which contributing to the development of giant cells and therefore leading the plants susceptible.

Key words: Prunus sogdiana, root-knot nematode, gaint cell, CCS52B gene