The Plant Pathology Journal

Fig. 2.

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Fig. 2. Sticky substances formed by S. padanus PMS-702 increase the suppressive efficacy of germination of sporangia produced by P. cubensis. (A) In-vitro assays of sporangial germination. PMS-702 was cultured in soybean meal-glucose (SMG), SMG amended with 1% coconut oil (designated SMG-C-1), or SMG-C-1 containing sticky substances (SMG-C-2) for 5 days. Cultural suspensions were mixed (1:1, v/v) with sporangia (104 sporangia/ml) to make 100× or 200× solution, and incubated at 20°C in the dark for 2 h. (B) In-planta assays of sporangial propagation on cucumber leaves. Spornagia treated with water (mock control) propagate quickly on cucumber leaves incrreasing 12-fold after a 5-day incubation. Sporangia treated with PMS-702 suspensions cultured in SMG-C-2 (200×) propagate much slower than mock control after 5 dai. Data are means of three biological replicates. Means indicated by different letters were significantly different according to the Fisher’s least significance difference test (P = 0.05). (C) Microscopic images of a sporangium treated with PMS-702 in SMG-C-2 for 24 h and stained with cotton blue, showing cytoplasmic aggregation (indicated by an arrow). (D) A germinating zoospore after released from a sporangium treated with water. Only reprenestatives are shown.
Plant Pathol. J. 2019;35:341-50
© 2019 Plant Pathol. J.