Impact of sugarcane rhizospheric selection on the Pseudomonas spp. community structure and genome evolution
L. LOPES (1), M. Pereira (2), E. Davis (3), A. Weisberg (3), C. Varize (2), J. Loper (3), J. Chang (3), F. Andreote (2) (1) University of Sao Paulo, Brazil; (2) University of Sao Paulo, Brazil; (3) Oregon State University, U.S.A.

The rhizosphere microbiome is directly related to plant growth and health. The Pseudomonas genus contains several species that can act as PGPR. Understanding the ecology and evolution of this genus is pivotal for increasing crops productivity. We hypothesize that (I) the plant roots imposes a selection effect on the Pseudomonas community and (II) that these selective pressures can also influence the genomic evolution of individuals. We collected 12 samples from the soil adhered (2-3 mm) to the roots of random plants (rhizosphere) or from the interlines (bulk soil) in a sugarcane field and used culture dependent (isolation with selective media and BIOLOG) and independent approaches (highthrouthput sequencing of 16S rRNA gene and qPCR) to test our hypotheses. The multivariate analysis using the OTU table of Pseudomonas reads showed that the community structure of this genus is different between rhizosphere and bulk soil (p<0.02; r2=0.74) and the qPCR results showed that the abundance of Pseudomonas is more than 10x higher in rhizosphere (p<0.01), confirming our first hypothesis. We obtained 80 Pseudomonas isolates (40 from each location) and the results of BIOLOG analyzed by a NMDS showed a trend of samples separation according to the location. To test our second hypothesis, we are submitting all 80 samples for WGS. We will perform comparative genome analysis between rhizosphere and bulk soil isolates aiming to find differences about the genes related to plant interaction.

Abstract Number: P4-99
Session Type: Poster