Fig. 4.

Principal Components Analysis (PCA) of bands corresponding to Bti and to Acinetobacter sp. (Additional file 1: Figure S1). The two bands for Bti were noted Bti1 (312 bp) and Bti2 (288 bp) and those for Acinetobacter sp. were Acin1 (681 bp) and Acin2 (649 bp). a 2D distribution of all samples analyzed in function of all pairs of bands analyzed (Bti1, Bti2, Acin1, Acin2). b, c PCA correlation circles in function of the first two components (b cumulated explained variance of 80.3%) and of the first and third components (c cumulated explained variance of 74.9%) showing a negative correlation between the two Bti and the two Acinetobacter band intensities. d Linear correlation of each band with the first three components, expressed by their cosinus, indicated a high level of positive (Bti1 and Bti2) and negative (Acin1 and Acin2) correlation with the first component. e Quality of representation of the four bands is indicated by their cosinus² (varies from 0 to 1, 1 being the best representation). This indicates that the four bands are well explained by the first three components