Figure 1.

Taxonomic differences between rhizospheres as revealed by between-classes PCA. The ade4 R package (Dray and Dufour, 2007) was used to plot two principal components based on data from prokaryotic and eukaryotic communities at the phylum and genus levels. The centre of gravity for each class of rhizosphere is given by the intersection of sample lines and the ellipse covers 67% of the samples belonging to that class. The closer two ellipses appear, the greater the similarity in their community makeup. The statistical significance of the between-classes PCA, as determined by a Monte-Carlo test (n=999), gave P<0.01 in all four cases, indicating the existence of highly significant differences between the groups.