Effects of the bacterial-fungal interaction between Tsukamurella paurometabola C 924 and Glomus fasciculatum and Glomus clarum fungi on lettuce microrrizal colonization and foliar weight

The study of fungal-bacterial interactions in soils is not only interesting from a basic point of view but has also yielded findings of societal and economical relevance, such as in the application of biological controls of plant diseases. This study evaluated the effect of Tsukamurella paurometabola C 924, a bacterium with nematocidal action isolated from banana rhizosphere, as single inoculant or combined with arbuscular mycorrhizal fungi (AMF) Glomus fasciculatum and Glomus clarum in lettuce (Lactuca sativa L.). Controls included non-bacteria non-AMF, and each AMF species alone. Five replicates were used. AMF did not show any influence, neither in T. paurometabola C 924 c.f.u. counts in soil, nor over its phenotypic nematocidal characters. On the other hand, the bacterium stimulated AM colonization for both fungi species as well as an early infection. Combined inoculation improved significantly fresh weight of plants as compared with the microorganisms separately or the non-inoculated control.