Phyllosphere and carposphere bacterial communities in olive plants subjected to different cultivation practices

The aim of this study was to characterize phyllosphere and carposphere bacterial communities of olive trees subjected for 13 years to two different soil management systems (sustainable and conventional) in a mature olive grove located in Southern Italy. Amplified DNA fragments of the 16S ribosomal RNA eubacterial gene (16S rRNA) of bacteria living on leaf and fruit surface, and in fruit pulp were analyzed by denaturing gradient gel electrophoresis (DGGE). A clone library of 16S rRNA amplicons extracted from the bacteria living in pulp homogenates and a phylogenetic analysis were performed. Generally, the DGGE patterns of the bacteria from both the treatments clustered separately. The medium-term sustainable orchard management resulted in a higher number of bacterial species from olive fruit pulp. Phyllosphere and carposphere communities evaluated by DGGE were affected by the type of the agricultural practices adopted. A better understanding of phyllosphere and carposphere microbiota of cultivated olive plants could be useful for the promotion of plant growth, a better plant protection and a higher crop quality.