Assessment of the Role of Chemotaxis and Biofilm Formation as requirements for colonization of roots and seeds of soybean plants by Bacillus amyloliquefaciens BNM339

YARYURA, PABLO M; LEÓN MARIANA; CORREA, OLGA S.; KERBER, NORMA L.; PUCHEU, NORMA L.; GARCÍA, AUGUSTO F.

CURRENT MICROBIOLOGY

Springer

Año: 2008 vol. 56 p. 625 - 632

0343-8651

This article correlates colonization with parameters such as chemotaxis, biofilm formation and bacterial growth that are believed to be connected. We show here, by using two varieties of soybean plants that seed axenically produced exudates, induced a chemotactic response in Bacillus amyloliquefaciens whereas root exudates did not, even when the exudates, also collected under axenic conditions, were concentrated up to 200 fold. Root exudates did not support bacterial cell division whereas seed exudates contain compounds that support active cell division and high cell biomass at the stationary phase. Seed exudates of the two soybean varieties also induced biofilm formation. B. amyloliquefaciens colonized seeds and roots, and plant variety significantly affected bacterial root colonization whereas it did not affect seed colonization. Colonization of roots in B. amyloliquefaciens occurred, despite of lack of chemotaxis and growth stimulation by root exudates. The data presented in this article suggest that soybean seed colonization but not root colonization by B. amyloliquefaciens is influenced by chemotaxis, growth and biofilm formation and that this may be caused by qualitative changes of the composition of root exudates.