The Plant Pathology Journal

Fig. 1.

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Fig. 1. Infection efficiency and virulence of six Acidovorax citrulli isolates through soil. (A) The seeds were sowed in soil infested with 106 cfu/ml of each indicated isolate. 10 mM MgCl2 buffer was used as a mock control. Watermelon seedlings showing typical symptoms, water-soaked spots, blotch or wilting, at 7 days after inoculation (dai). The red and yellow arrows in left pictures indicate severe blotch and weak symptom, respectively. Right pictures are representatives of seedlings showing the most severe symptoms. (B) The disease severity by bacterial isolates at 10 dai and 13 dai that was scored according to the following disease index scale: 0, no symptoms; 1, slight water-soaking spots on cotyledon; 2, massive water-soaking or necrosis spots on cotyledon; 3, bending of stem; 4, falling stem; 5, necrosis of whole plant (). Bars represent standard error (n = 20). (C) Confirmation of the presence of inoculated bacteria by PCR. The colonies isolated from infiltrated leaves were confirmed by PCR using the 16/25S rRNA gene primer set. M, 1 kb ladder marker; P, Ac0 genomic DNA (positive control); N, H2O (negative control). (D) Bacterial cell numbers in watermelon seedlings at 7 dai and 10 dai. Y-axis represents mean Log10cfu/g of watermelon, and bars indicate standard error (n = 4). The letters on top of error bars show results from Duncan’s multiple range test (P < 0.05).
Plant Pathol. J. 2020;36:29-42
© 2020 Plant Pathol. J.