|Dileone, Julie - USDA-ARS-HCRL|
|Soeldner, A - USDA-ARS-HCRL|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2002
Publication Date: June 1, 2002
Citation: Sechler, T.M., Mahaffee, W.F., Press, C.M., Roche, M.M., Dileone, J., Soeldner, A.H. Microscopic Evaluation Of Phyllosphere Colonization By A Biofilm-Forming Biocontrol Agent. Interpretive Summary: Described is the evaluation and development of microscopic methods to assess bioflm formation on leaf tissue. Biofilms are large aggregates of microbe cells that are thought to be very important in colonization of biocontrol agents on leaf surfaces.
Technical Abstract: Biofilms of the biocontrol agent, Burkholderia sp. strain FP62, in the phyllosphere of geranium leaves were viewed using both fluorescence compound light microscopy (FCLM) and conventional scanning electron microscopy (SEM). Initial work was done by staining with acridine orange and viewed using FCLM. Average number of biofilms was 6, 8.5, and 7 biofilms per cm2 leaf area, 6, 12, and 22 days post-inoculation (respectively) on inoculated geranium leaves. Biofilms were strongly associated with trichomes and stomates. They were also observed to be formed on the stalks and bulbs of glandular trichomes. Similar colonization patterns of FP62 were observed on inoculated geranium leaves using SEM techniques. Biofilms 7-day post-inoculation were many cell layers thick and embedded in a smooth polymer-like matrix with bacterial cell-associated fibril strands. On average FP62 biofilms spanned the area of 20 epidermal leaf cells, where some spanned as many as 200 cells. Biofilm formation by FP62 appears to be associated with biological control of Botrytis cinerea and FP62 survival on the leaf surface.