Induced expression and activity detection of Polygalacturonaseinhibiting protein in 5 kinds of cucurbits crops

Polygalacturonase-inhibiting protein (PGIP) is a leucine-rich repeat cell wall-binding protein that can inhibit the activity of fungal PG specifically and non-competitively, thus improve the disease resistance of plants. Cucurbitaceae cucumis, Momordica charantia, Benincasa hispida, Benincasa hispida var. chieh-qua and Cucumis melo seedlings were selected in this research. Biotic stressed plants of C. cucumis showed high induced expression activity, rose up to maximum at 48 h and stems showed maximum expression than other organs. Biotic stressed plants of 5 kinds of cucurbits crops are used to prepare crude inhibitor and their activity was checked by inhibition assay to 6 kinds of PG respectively, PGIP of M. charantia showed high activity than others PGIP. The results showed a wide spectrum of activity of PGIP against different PG and there might be selective inhibition.