NOD FACTOR THIN-LAYER CHROMATOGRAPHY PROFILING AS A TOOL TO CHARACTERIZE SYMBIOTIC SPECIFICITY OF RHIZOBIAL STRAINS - APPLICATION TO SINORHIZOBIUM-SAHELI, SINORHIZOBIUM-TERANGA, AND RHIZOBIUM SP STRAINS ISOLATED FROM ACACIA AND SESBANIA
G. Lortet et al., NOD FACTOR THIN-LAYER CHROMATOGRAPHY PROFILING AS A TOOL TO CHARACTERIZE SYMBIOTIC SPECIFICITY OF RHIZOBIAL STRAINS - APPLICATION TO SINORHIZOBIUM-SAHELI, SINORHIZOBIUM-TERANGA, AND RHIZOBIUM SP STRAINS ISOLATED FROM ACACIA AND SESBANIA, Molecular plant-microbe interactions, 9(8), 1996, pp. 736-747
Rhizobia isolated from Acacia or Sesbania belong to several taxonomic
groups, including the newly described species Sinorhizobium saheli, Si
norhizobium teranga, and the so-called cluster U. A collection of stra
ins belonging to these different groups was analyzed in order to deter
mine whether the host range of a strain could be correlated with vario
us molecular nodulation determinants, Nodulation tests showed that, in
dependently of their taxonomic position, all the strains isolated from
the same plant genus exhibited a similar host range, which was differ
ent for Sesbania and Acacia isolates. The fact that S. teranga strains
nodulate either Acacia or Sesbania led us to subdivide this species i
nto biovars acaciae and sesbaniae. Thin-layer chromatography (TLC) ana
lysis of the Nod factors synthesized by overproducing strains showed t
hat (i) strains isolated from the same plant genus exhibited similar T
LC profiles and (ii) profiles of Acacia and Sesbania symbionts were ea
sily distinguishable, Acacia strains producing, in particular, sulfate
d molecules. In contrast, no correlation could be established between
the host range of a strain and its plasmid content, the nature of the
nod gene inducers or the presence of DNA sequences homologous to speci
fic nod genes. We thus propose that Nod factor TLC profiling may be us
ed as an easy and powerful tool for the classification of rhizobial st
rains on the basis of their symbiotic properties.