Fig. 5. Scheme describing the genetic repertoires of the six community classes.

Pathways from the KEGG database that were most relevant for describing the classes are shown. We ranked the mean proportion of genes in each pathway (see Supplementary Results 3), indicated by the size of the circles (Fig. 4). Only classes with significant pairwise post hoc comparisons are shown. P. putida (grey) and Serratia (blue) classes appear to dominate orthogonal pathways. We therefore indicated how the pathways were influenced by the dominant community (indicated by the arrow colour). The link between the TCA cycle and amino-acid synthesis (black arrow) is unclear. We further illustrate the substrates and hypothetical environmental conditions expected for Serratia (rain/cold) and P. putida (dry/hot) communities. We suggest the other communities are intermediates between these two classes. The Paenibacillus class, with a large number of sporulation and germination genes, may reflect conditions of very low nutrient availability.