Fig. 1.

Major bacterial populations detected in growing cluster roots of white lupin (L. albus L.) by 16S rRNA sequencing of isolates (A) and clone libraries constructed from root-extracted DNA (B). JUV, juvenile cluster roots; MAT, mature cluster roots; SEN, senescent cluster roots. All but a few sequences (3 for isolates and 4 for clones) could be assigned with high confidence (≥97% for isolates and ≥94% for clones) to known genera. The relative abundance of each genus is shown as a percentage. The relative abundance of isolates or clones belonging to the genus Burkholderia was compared between root stages using the chi-square test. Different letters within the columns indicate statistically different values (P < 0.05).