Clustering relationships between endophytic microbial communities based on principal component analysis (PCA) of bacterial DNA fingerprints (both 6FAM and Max550 labelled 16S rDNA TRFLP fragments). Shown are endophytic community groupings including: (A) soil, seed, shoot and root data; (B) only shoot and root data. Parviglumis root samples are underlined in brown, Mixteco roots in green, and Pioneer roots in blue. Results are displayed as biplots of the first and second principal components, with vectors representing the different samples; vector length represents the amount of variation in that sample, and angles between vectors represent the degree of variance between samples. Abbreviations: PI, Parviglumis; MI, Mixteco; PA, Pioneer 3751; Can, Canadian soil; Mex, Mexican soil; sand, sterilized sand.