Impact of plant domestication on spermosphere and rhizosphere microbiome composition

Microbiome composition of the spermosphere and the rhizosphere of wild and modern bean accessions grown in an agricultural and a native soil from Colombia was characterized by metagenomics and cultivation-dependent approaches. A higher relative abundance of Bacteroidetes, mainly Chitinophagaceae and Cytophagaceae, was observed in the rhizosphere of wild accessions while an increase in relative abundance of Actinobacteria and Proteobacteria was observed in the rhizosphere of modern accessions. These divergences associated with differences in specific root length (SRL). Using 16S-rDNA data from other studies revealed that also wild relatives of other crop plant species presented higher relative abundance of Bacteroidetes. Additionally, bean accessions were grown in a native and an agricultural soil from Colombian. The transition of common bean from a native to an agricultural soil led to a gain of rhizobacterial diversity and to a stronger bean genotype-dependent effect on microbiome assembly. In addition, during seed imbibition and germination, significant differences were detected between the spermosphere microbiomes of wild and modern bean accessions. A domestication effect on microbiome assembly already at this early developmental stage was evidenced. The research presented in this thesis showed that domestication of common bean had a significant effect on the composition of the microbiome.