Bacillus-based biocontrol of fusarium disease on tomato cultures in Burundi.

The biocontrol potential of a Plant Growth-Promoting Rhizobacterium (PGPR) Bacillus subtilis S499 on tomato was studied in open field sites in low attitude area of the plain of Imbo in Burundi. Application of the PGPR strain on seed before sowing have significantly increased growth and fruit yield of tomato plants in addition to its remarkable control of a local important disease caused by a fungus type-Fusarium.. This pathogen causing large tosses in Burundi tomato plantings is closely related to Fusarium semitectum based on a preliminary identification. Results obtained in open field assays from two successive years on the same site demonstrate that treatment with B. subtilis S499 strain suspensions significantly increase growth and fruit-yield and provided a high level of protection of tomato plantings against the new fungal disease apparently uncontrolled by routine chemical pesticides.

Adherence and colonization properties of Lactobacillus rhamnosus TB1, a broiler chicken isolate.

AIMS: Selected lactic acid bacteria (LAB) isolated from intestinal tract of chicken have been studied in order to investigate their ability to adhere in vitro to Basement Membrane Matrigel (BMM). A selected strain showing a good adherence in BMM test was used for in vivo colonization assays. METHODS AND RESULTS: In vitro assessment of adhesion of broiler chicken isolates was performed using BMM assay. Among LAB strains tested, Lactobacillus rhamnosus TB1 showed a good adherence that was comparable to the one of an Escherichia coli EPEC strain used as positive control. For in vivo colonization assays this strain was fluorescently stained with the carboxyfluorescein diacetate succinimidyl ester (cFDA-SE) thus allowing its detection in different layers of intestinal tract after inoculation in broiler chicken. Further, stained L. rhamnosus were found with a highest value in rectum, jejunum and ileum both 3 and 24 h after administration. CONCLUSIONS: BMM assay is a quick method to test in vitro adhesion properties of bacterial strains and cFDA-SE-stained bacteria may be considered as an alternative method to test in vivo adhesion and colonization properties. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus rhamnosus TB1 was therefore showed to be able to adhere strongly in vitro to BMM and in vivo to intestinal epithelial cells of chicken and may be considered as a potential probiotic for chicken.