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Title: THE IMPACT OF HABITAT PATCHINESS AND BACTERIAL GENOTYPE ON SPREAD OF BACTERIA IN THE PHYLLOSPHERE

Author
item HIRANO, SUSAN - UNIV OF WI
item RIELY, BRENDAN - UNIV OF WI
item FOURRIER, KEITH - UNIV OF WI
item BAKER, L STUART - UNIV OF WI
item Upper, Christen

Submitted to: Biotechnology Risk Assessment Symposium
Publication Type: Proceedings
Publication Acceptance Date: 11/30/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Spread of an organism requires both dispersal to a new habitat and reproduction on that habitat. We sought to examine the impact of the patchiness in the agricultural environment and differences among bacteria adapted to live on aerial plant parts on the likelihood of spread of such bacteria. We addressed two factors for their effect on bacterial spread in nfield experiments: the effects of the surface over which bacteria travelle and the ability of bacteria to grow. Our findings included: Bacteria can spread very rapidly on newly emerged bean plants. The presence of a plant suitable for growth (i.e., snap bean) of two strains of the bacterium Pseudomonas syringae did not facilitate spread of these bacteria. Surfaces that did not support growth (i.e., bare ground or soybean) of P. syringae strains did not impede spread. The two P. syringae strains differ in their abilities to grow on bean plants under field conditions. On the other hand, the strains apparently were dispersed to a similar extent. Differences in relative amounts of spread between the two strains, then, is presumably due to their differential growth abilities on bean leaves.

Technical Abstract: Our overall objective is to examine the impact of the patchiness of the agroecosystem and the variability of bacterial adaptation to the phyllosphere on the likelihood of spread of phyllosphere bacteria. Two specific objectives were addressed in field experiments: To assess the effects of the substrate over which bacteria adapted to the phyllosphere must travel on spread and the ability of bacteria to grow in the phyllosphere on the likelihood of spread. Key findings included the following: Bacterial spread can occur very rapidly on newly emerged bean plants. The presence of a substrate suitable for growth (i.e., snap bean) of two strains of Pseudomonas syringae did not facilitate spread of these bacteria. Substrates that did not support growth (i.e., bare ground or soybean) of the P. syringae strains did not impede spread. The two P. syringae strains examined were known to differ in fitness on bean plants under field conditions. The strains appeared to be similar in ability to be dispersed. However, they differed in relative amounts of spread presumably due to their differential growth abilities on bean leaves.