Colonization of seeds and roots of two soybean varieties by Bacillus amyloliquefaciens BNM339 is affected by the corresponding exudates

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

Fundación Instituto Leloir, Ciudad Autónoma de Buenos Aires

Congreso; IV Congreso Argentino de Microbiología General; 2007

Sociedad Argentina de Microbiología General (SAMIGE)

The performance of a plant growth promoting rhizobacteria (PGPR) depends on effective plant root colonization. Moreover, chemotaxis and biofilm formation have an important role in the stable bacterial attachment to root surface. Our aim was to determine whether soybean variety affects root colonization by a PGPR that we isolated in our laboratory. We also studied the effect of seed and root exudates on bacterial chemotaxis response and biofilm formation. In addition, we performed chemical analysis of root and seed exudates, in order to establish some differences between them. Root colonization of Bacillus amyloliquefaciens BNM339 was determined in two soybean varieties, FN 4.10 and FN 4.85, which were grown in a plant growth chamber, under hydroponic conditions. Root and seed exudates were collected from axenic plants growing under controlled conditions. Bacterial root colonization was affected by the soybean variety; FN 4.10 showing a higher bacterial count per g of rhizoplane dried weight than FN 4.85. Seed exudates stimulated bacterial chemotaxis more than root exudates, and also stimulated biofilm formation, both phenomena displaying a significant plant variety effect. Seed and root exudates showed differences in amino acid and carbohydrates composition also in a plant variety depended fashion. The composition of root exudates was dependent on plant age. According to our results, soybean variety was the main determinant of B. amyloliquefaciens BNM339 colonization, chemotaxis and biofilm formation and these responses may be related to the composition of plant exudates