Resumo

Sugarcane is an important Brazilian agricultural system crop and presents in a currently expansion. Nevertheless, land use, and implementation of different plant and soil management technologies have originated changes in the environmental balance, where important microbial interactions occur as essential for plant development. Among the wide diversity of soil microorganisms, the mycorrhizal fungi are highlighted as organisms closely associated with plant roots, in any way, to obtain water and nutrients. As consequence of the mutualistic interaction these fungi, also interact with other soil organisms, such as, bacteria. Thus, the present work aimed to study the dynamics of interaction between sugarcane and arbuscular mycorrhizal fungi Glomus clarum (AMF) in soils with different bacterial community compositions. The methodology used was “dilution to extinction”, which serial dilutions (10-1, 10-3, 10-6 and 10-9) of a natural soil were used to inoculate a sterile soil. On this basis, these microcosms were monitored along a period of 60 days over roots colonization rate and bacterial community structure. As a result, we observed a higher colonization of sugarcane roots in the treatments inoculated with lower dilutions of the original community (natural soil and dilutions 10-1 and 10-3), and likewise was observed a distinction between these bacterial community structure. Establishing correlations between microbial groups and the percentage of mycorrhizal colonization (PCM), it was possible to name, based on the massive sequencing of the region V6 ribosomal gene 16S rDNA, changes in groups of Actinobacteria; Bacteriodetes; Firmicutes, Proteobacteria; Cyanobacteria, Chloroflexi and Acidobacteria, when related to the increase of micorrhization and plant roots development. In conclusion, this work demonstrates the dependence of an important process, such as the AMF micorrhization, has to soil bacterial community, and indicates that soil degradation may impact the bacterial community less abundant which may be crucial to the efficiency of some process in soil.