Multiplication of Pseudomonas syringae pv. phaseolicola "in planta" |
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Authors: | K. Rudolph |
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Affiliation: | K. Rudolph;, Institut für Pflanzenpathologie und Pflanzenschutz, Grisebachstrße 6, D-3400 Göttingen, West-Germany. |
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Abstract: | Multiplication of Pseudomonas phaseolicola was determined in 17 different bean cultivars ( Phaseolus vulgaris ) and 9 other plant species, and the effect of different inoculation methods and conditions was also studied. In susceptible leaves, a generation time of 2.1 h was determined in the early phase (2 days after inoculation). Different multiplication rates in susceptible and resistant leaves were clearly observed 4 days after inoculation. At this time the first small water-soaked spots were visible in the susceptible cultivars. Bacteria multiplied up to the 7th day after inoculation with a maximum of 109 cells per cm2 leaf (equal to ca. 4 × 1010 bacterial cells/cm3). At the same time, the water-soaked spots had reached their maximum size in most cases. Thus, bacterial multiplication and development of water-soaked spots paralleled each other. In resistant leaves, no water-soaked spots appeared, and the final bacterial concentration was 1/1000–1/100 of that in susceptible leaves. Gomparison of races 1 and 2 in several bean cultivars indicated the non-existence of a gene-for-gene relationship with this disease. Old leaves were less susceptible to infection. Some bacterial multiplication was also observed in non-host plants. There was a general correlation between bacterial multiplication in the non-host plants and their botanical relation to Phaseolus vulgaris . |
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