Fig 1.
Schematic illustration for the preparation of plant-only teabags culture media, and the work flow of culture-dependent and culture-independent analyses of Lucerne rhizobacteria.
Fig 2.
Cultivable rhizobacteria of Lucerne roots (CFUs g-1 root) developed on all tested culture media.
A, ANOVA analysis (2-way interactions) of CFUs numbers of Lucerne rhizobacteria as affected by culture media and incubation period. NA, nutrient agar; LP1g, teabags of Lucerne powder 1.0 g l-1; LP4g, teabags of Lucerne powder 4.0 g l-1. B, Morphology of CFUs developed on agar plates of culture media prepared from teabags-only-containing Lucerne powder (4.0 g l-1 and 1.0 g l-1 culture media) as well as nutrient agar, inoculated with aliquots of 200 μl of the same root suspension (10−4): B1, confined/limited and transparent/translucent colonies on LP1.0 g l-1; B2, numerous slimy colonies on LP4.0 g l-1; B3, large tinted colonies on NA.
Table 1.
The culturability of Lucerne rhizobacteria on various culture media.
Fig 3.
Cluster analysis of culturable Lucerne rhizobacteria (CFUs) developed on all tested culture media.
A, UPGMA cluster analysis, with Euclidean distances, of 16S rDNA-DGGE pattern obtained for culturable populations (CFUs) developed on agar plates of culture media prepared from Lucerne powder-only-teabags (4.0 g l-1, 1.0 g l-1, 0.5 g l-1 and 0.25 g l-1 Lucerne powder) as well as standard I nutrient agar (NA). B, The principal coordinate analysis of the obtained DGGE fingerprints.
Fig 4.
Medicago sativa rhizobacteria isolates phylogeny based on 16S rDNA sequences.
The isolates of this study are indicated by solid circle (●) (LP1.1, LP1.2, LP1.3, LP2.2, LP3.1, LP3.2, LP3.3, LP3.4, LP3.5, LP3.7, LP3.8, and LP3.11), and closest matches obtained from the GenBank database are indicated by accession numbers after organism name, using Neighbor-Joining method with calculated Jukes-Cantor distances. Bacillus spp. were included as an out-group to root the tree. The node numbers return the bootstrap values after 1000 replicates.
Table 2.
Growth performance of a group of rhizobacteria isolates of Lucerne, originally developed on Lucerne-powder culture medium, on commonly-used chemically-synthetic culture media.